What is the best wall construction for Passive House?

A recent article in the Home Energy Magazine analyzes the embodied energy of different wall structures for Passive House construction in cold climates. Basically, it’s great to have super insulated homes, but home much extra energy does it take to build them? Said another way, how many years will it take before the embodied energy it took to build the walls becomes less than the energy those walls saved.

They compared the following wall structures

  •  TJI frame with blown-in fiberglass insulation, built in Urbana, Illinois.
  • Insulating concrete form (ICF) with exterior expanded polystyrene (EPS), built in southern Wisconsin.
  • Structural insulated panel (SIP) filled with urethane foam with an interior 2 x 4 wall filled with blown-in cellulose, built in Belfast, Maine.
  • Advanced 2 x 12 stud framing filled with open-cell spray foam and insulated on the exterior with either EPS or vacuum insulated panels (VIPs), built in Bemidji, Minnesota.
  • Double 2 x 4 stud wall insulated with blown-in cellulose, built in Duluth, Minnesota.

The energy payback time for the wall assemblies ranged from immediately for the double-stud wall to 4.4 years for the mass wall—not a big chunk of a building’s expected lifetime. Because of the HFC blowing agent, the advanced frame with spray foam envelope has a carbon payback of 23 years.

Although the double-stud wall comes out smelling of roses in these comparisons, as long as you avoid specifying insulation made with an HFC blowing agent and minimize the use of energy-intensive materials, such as concrete and OSB, all of these envelopes would have a good energy and carbon payback.

Here is the double studd wall with cellulose:

The double studd walls stop thermal bridging while the cellulose insulation has very low embodied energy.
The double studd walls stop thermal bridging while the cellulose insulation has very low embodied energy.

As a New York Passive House builder the big question for me is how does this affect Passive Houses built in existing Brownstone buildings. The double stud and cellulose can easily be applied on the inside of the Brownstone brick walls. But there are two problems with this.

One problem is space. Brownstones cost a lot of money and to loose an extra several inches of floor space is a big deal.

The second problem is deterioration of the brick walls. Those brick walls have survived wonderfully for the past 100 years thanks to the nice warm heat from the building. Once you install the double stud walls you isolate the brick on the outside of the thermal envelope and the bricks are susceptible to freezing.

When the mortar in a brick wall freezes it expands. When it thaws it contracts. Over the years this wears away all the mortar and the wall falls apart. How long this takes is still a bit in the air since all Passive Houses in NYC and Brooklyn are only a couple years old.

One solution to both these issues is to build a less thick wall. You gain space and a little heat is lost to the outside, stopping the bricks from freezing. Clearly this is not ideal given the lost energy.

If anyone has solutions to these issues I am very interested to hear them.

Building Passive House with Hempcrete

One of the challenges we face when doing High Energy retrofits of NY masonry brownstones, by the Passive House standard for example,  is how to install insulation that will both be effective and maintain the historical integrity of the building. Most existing insulation materials have limited usefulness when installed on the interior of the envelope, due to condensation risk and potential freeze-thaw issues.

Enter Hempcrete. Hemp-lime insulation, due to its vapor permeability and the material’s virtual thermal mass, has proven to be an effective way to retrofit historic masonry buildings for improved insulation, and is now being used widely throughout Europe.

This opens up exciting possibilities for effective and affordable ecological renovations of New York’s many historical brick buildings.

Although well established in Europe, this technology is new to the USA. We have studied it a lot and Eco Brooklyn is eager to be a NY hempcrete installer. Since hempcrete can be either insulation or actually act as an insulating semi-structural material (like SIPs but without the plastic), we think that it offers a lot of options for high efficiency NY Brownstone renovations.

Best Urban Space Remodels: Our Instagram Claim to Fame

In the spirit of awards season, we’re pleased to announce that our green building Instagram account has been awarded an Instagrammy! Improvement Center evaluated the top ten home contractors to follow and we’ve been recognized for having the best urban space remodels.

Our feed features images from our Manhattan and Brooklyn ecological construction projects including gardens, green roofs, renovated shipping containers, passive brownstones, and more. In addition to project updates we include tips on green construction and sustainable design, a behind-the-scenes look at our salvaging techniques, and ways to save energy and reduce your carbon footprint.

Big thanks to Improvement Center and be sure to take a peek at our Instagram account under the handle @ecobrooklyn.

Red Hook container studio built from salvaged materials with a rooftop garden
Red Hook container studio built from salvaged materials with a rooftop garden

Praise for Siga high-performance tape

As a Green Builder we are always looking at the newest developments in green design. Today the folks from Siga were kind enough to come by and show us their energy efficient air sealing products.

We recently finished a Passive House renovation of a Harlem brownstone and worked closely with the air sealing supplier 475. They sell Pro Clima tape and it worked really well.
Siga seems like a great product too and I welcome the increase in air sealing options to the NY market.
The three key benefits of Siga are its outstanding adhesive qualities (its sticks to any surface), its vapor permeability, and its rain driven protection. Not to mention all their products are VOC free and are made with green technology.
They are certainly worth checking out: http://www.sigacover.com/us/

Klearwall PH Windows


As New York passive house builders, Eco Brooklyn gets approached by many distributors offering Passive House   products. Recently Klearwall, a PH window company located in Ireland, informed us of their intended expansion in New York City. Klearwater offers thermal bridging calculations, which shows how much energy will be conserved by the instillation of their triple pane windows. The windows are PH certified and manufactured in a plant powered by renewable energy.  The plant is carbon neutral and harnesses its energy from two on site wind turbines and a co-gen plant.

Check them out!




Subterranean Living

Inhabitat recently posted an article exemplifying innovative underground houses around the globe.  As a green contractor Eco Brooklyn is continually using cutting-edge ideas to improve upon Passive House designs. Underground housing can provide New York State with low energy housing at reasonable prices without sacrificing the aesthetic appeal of living above ground.

Living Passively
Living Passively

Structures built underground are protected from large temperature swings and extreme weather. At depths below 3 feet the ground maintains an average temperature of the yearly climate. In the wake of Hurricane Sandy, the benefit of home protection is priceless. The greatest benefit to homeowners is one that benefits their wallet. These buildings utilize the earth’s natural insulation and thus require less energy to heat and cool. Besides saving energy, subterranean buildings provide security though access limitation. They exist within nature instead of disrupting the environment. Under-grounding takes up less space and is less environmentally invasive. Unlike standard housing, driveway and backyard space are unnecessary as those amenities are provided directly above the structure.

One of the novel designers of earth-sheltered housing was Malcolm Wells. His underground designs merged iconoclastic principles with modern architecture. The New York Times stated it best:

“…his designs incorporated the land. He designed some homes (and other buildings) that seemingly burrowed into hillsides, and others whose main living space was subterranean, perhaps with above-ground lean-to roofs or atria and skylights to let in the sun. In general, his roofs were covered with layers of earth, suitable for gardens or other green growth.”

Wells Art Gallery

Much of Malcolm Wells’ design incorporated concrete and Eco Brooklyn suggests using rammed earth or tires to add structural support to underground buildings. Gennaro has also developed a design to alleviate the stress of the barrier walls by engineering a bowl-shaped structure with a one-to-one slope.

EcoBrooklyn Undergound House

Eco Brooklyn is currently working with Michael Reynolds to develop an earth-sheltered home just north of New York City, so check back for updates on our Underground Housing

-Anthony Rivale

Earthship Project in New York

We are earthship enthusiasts here at Eco Brooklyn, and are currently speaking with a client who wants to build an earthship in New York State. Here are some ideas being thrown around between Michael Reynolds, Eco Brooklyn, and the client, that we may be able to help turn into reality. The schematic of this global model earthship shows an additional greenhouse that will provide greater temperature stabilization, which would be better suited to New York’s climate, and will provide additional grow space as well. The earthship will of course be capable of functioning independently from the grid. As a Brooklyn Green Contractor, this is a great project that we are excited to be involved with.


earthship schematic 1

earthship 1

earthship 2

earthship 3

earthship 4 All images are property of Earthship Biotecture.

– Liza Chiu

DIY Indoor Vermiculture Composting

If you are a fan of living sustainably you have most likely felt the urge to reduce your waste and begin composting. But living in New York City often leaves residents without much outdoor space. A large part of Green Building in Brooklyn involves meshing innovative techniques with salvaged materials, which is why do-it-yourself composting is a fantastic solution to a massive problem. Eco Brooklyn is a big fan of “Passive House”  philosophy and indoor composting is as energy conscious as it is environmentally friendly. Composting indoors sounds, or rather “smells,” fishy right? In fact if your compost is smelly it’s probably not functioning correctly.

Black Gold
Black Gold

Composting is a simple process by which organic material, mostly complex carbon and nitrogen molecules, are broken down to produce the basic building blocks to support plant like organisms. This compost or “black gold” is essential to reducing the wasted-tons of organic material sent to landfills every time one throws away those banana peels, coffee grounds and filters, or even used paper towels.

With a little human energy and a bit of patience, one can easily turn their two-pound-per-day organic waste into nutrient rich soil for their house plants or garden. The first step is to find a suitable container with at least four cubic feet of volume; basically a trash can with a diameter of 1.5’ and a height of 2’. The container should be salvaged or recycled, must have a lid, and bigger is better if you have the space.


This compostee used an old paint bucket and found a solution to reducing those pesky fruit flies. Her method suggests adding felt to the inside of the aeration holes to prevent any unwanted invaders. I imagine using the activated carbon mesh found at pet stores for cat litter boxes would also do the trick while reducing any unwanted odors.

Keep the Flies Away
Felt on Aeration Holes


Use to Prevent Pests and Odors
Use to Prevent Pests and Odors



Next you will want to find a suitable tray to place underneath the compost bin with some newspaper in case of spillage. The bin should be place in a dark place for best results. Usually under the kitchen sink or on the floor of a pantry will do. Add some soil from anywhere, except near the Gowanus.


Then mix in around four pounds of red worms, depending on how much suitable waste you generally produce, as they will eat about half their weight in material every day. Aeration holes are critical as they allow oxygenation for the worms and the aerobic (need oxygen) bacteria. Foul smelling compost is usually due to “anaerobic” (do not need oxygen) bacteria, so make sure to churn your compost once a week and have at least a dozen ½” size holes in the lid or the top sides of the bucket.


What can you add to your compost bin? Here is a great list of 81 items suitable for composting. Keep in mind that a higher concentration of carbon rich material; “brown stuff”, newspaper, paper towels, wood clippings, will prevent ammonia smells caused by the anaerobic breakdown of nitrogen rich material; “green stuff”, fruit, veggies, coffee grounds.

DIY Composting Bin
“I’m Red, but I produce Black Gold”

Composting generally takes a few weeks, but this wait is very rewarding. It is probably best two have at least two bins as one will get full after a couple weeks and it will need time to mature, which is a great time to start your second compost bin. Also make sure to add “brown” material with your “green” stuff and sometimes a little water if it is too dry or newspaper if it is too wet. Then churn, churn, churn, because there is always a season for composting.

Too much compost? Donate your extras to a local farm or farmers market. The NYC Green Markets are also happy to take your clippings, and “green” waste for composting.

-Anthony Rivale

Eco Brooklyn Interview

BBox radio did a cool interview of Eco Brooklyn Director, Gennaro Brooks-Church. We discussed all sorts of things in the field of radical green building – Net Zero, Passive House, Guerrilla Green Building, Build It Forward and much more.

Check it out here! 



Das Haus: First NYC Passive House in BK

For those of us who live in historic homes we know that our period dwellings bring us both joy and frustration. The frustration is largely attributed to the endless repairs that classic Brooklyn Brownstones require and their not so efficient envelope.

Eco Brooklyn has renovated many brownstones and knows first hand how challenging it can be to air seal and insulate an building while still keeping it’s traditional character.

With the advent of new energy efficient building techniques Eco Brooklyn is part of a new trend in Brownstone renovation: instead of following traditional guidelines to fixing up a house, some Brooklyn homeowners are transforming their townhouse into a Passive House – a German technique that can reduce a homes energy consumption up to 90%.

This past week, the Eco Brooklyn interns took the metro North train up to White Plains for the Das Haus Symposium. There were a number of speakers, some coming all the way from Germany to talk about projects, ideas and products that have either already migrated to the US or are on their way. The Passive House concept was a topic of interest.

The Passive House standard focuses on 5 main strategies:

  1. Insulate strategically
  2. Stop Thermal Bridging
  3. Achieve air tightness
  4. Install high-performing windows for thermal comfort
  5. Reduce mechanical systems with heat recovery ventilation

Jordan Goldman, the engineering principal at Zero Energy Design was a speaker at last week’s symposium. He is a Passive house consultant who recently finished a passive house restoration at 23 Park Place in Park Slope. The completion of this project marked the first certified Passive House in New York City!

The original structure at 23 Park Place was built in 1899 and had been owned by a few artists until it was abandoned a few years ago. After the new owners purchased the dilapidated property they decided to do a Passive House retrofit on the existing structure. Julie Torres Moskovitz from Fabrica718 was the lead architect on the project. She enlisted Jordan Goldman as the engineering consultant on the design.

Since this property was not land marked the retrofit became a complete makeover for the structure. For instance, all the fireplaces and chimneys were replaced to increase the overall air tightness of the space.

As noted before, air tightness and a system of interior and exterior air exchange are the key stone elements to creating  a cohesive thermal envelope ensuring maximum energy reduction.

23 Park Place met the air tightness requirements of a passive house, and far surpassed the requirements of NYC. 23 Park Place is not only 15 times tighter than a current building norm is achieved the highest air tightness level in all of New York City-  .38!

In addition to the insulation, comprised on 23 inch thick walls and three pane windows

Passive House calls for all the joists and meeting points to be sealed to create a continuous thermal envelope.

Although after so much emphasis on the insulation, you must be wondering how could anyone possible endure such stuffy conditions. The answer to this seemingly uncomfortable air is the energy recovery ventilator or E.R.V.

Essentially, the inside air is pulled through the ventilator, the heat is then transferred to a membrane, the air is cooled and then exits as exhaust. The fresh air outside is simultaneously being pulled in and warmed by the membrane. This system, which is referred to as “counterflow” maintains a constant temperate within the thermal envelop.

The Passive House energy use standards are far more stringent then those used by the US Green Building council, which issue certifications for LEED and the Energy Star program. It is considered excellent if a LEED certified structure can reduce energy consumption by 30% and Energy Star homes typically save about 15 to 20%.  With a Passive House there can be up to a 90% reduction in heating and cooling.

Now that’s a paradigm!

Fortunately there are a number of Passive House projects underway in New York City, many of which are located right in Brooklyn. As a New York Passive House builder we hope to see an increase in the demand for Passive House design in the upcoming years. It costs within the range of normal construction yet greatly decreases a building’s impact on the environment.

Das Haus New York

green builder brooklynLast week, the interns from Eco Brooklyn went to the Net Zero Symposium sponsored by Das Haus in White Plains, New York to hear lectures and view a model of Das Haus, a passivhaus model made from two shipping containers that functions completely off the grid.  The conference was held at the White Plains Public Library and about 100 people were present.


Das Haus (German for “The House”) is a traveling pavilion featuring German innovation in photovoltaics and energy efficiency. Das Haus is calling on ten cities across North America.  Das Haus tour hopes to accomplish two goals: introduce North America to Germany’s innovations in solar energy and green construction, and create an ongoing dialogue across the country about policies, construction materials and techniques, etc., regarding sustainable design.


During the Das Haus conference in New York, the lecturers were a mix of Germans and Americans.  The Americans who spoke are based in New York and addressed what is going on in the state.

Das Haus tour New York


Guy Sliker, from the New York Power Authority personified the attitudes of the typical American: America knows best, we’re number one, look at all that we have accomplished, go America!  Mr Sliker spent the majority of his speech listing numbers that prove these (mis)conceptions.  Mr Sliker was overconfident in New York Power Authority’s progress and too comfortable is the direction the ship is sailing.


Net Zero symposium New York

Kim Curran, PV Instructor from the Bronx Community College, gave a distilled explanation of how PV works and the challenges the industry is facing.  She gave a more realistic picture of the solar industry and the problems it is facing, such as bringing down cost, increasing efficiency, and the state of government incentives.  Kim’s and most of the other presenters’ presentations can be viewed here.


It is an amazing thing that some of Germany’s technology is coming over the pond to North America.  Germany has been using PV panels, energy efficient designs, and green roofs for decades and are lightyears ahead of North America in their development, understanding, and implementation of sustainable ideas.  This is a giant step for progress in North America.


The Living Building Challenge- Winner of the 2012 Buckminster-Fuller Challenge

Green building and eco-sensitive design is currently at the forefront of our modern ethos.   What this means for the green builders, contractors and architects of NY, and the world, is a period of dramatic change and challenge is ahead if not already begun. A change in the way we think about new buildings and construction, in how we consider “used” materials and how we use and interact with space.

As Scholar David Orr stated-

“We are coming to an era the likes of which we’ve never seen before, we’re in the white waters of human history. We don’t know what lies ahead. Bucky Fuller’s ideas on design are at the core of any set of solutions that will take us to calmer waters.”


One of the most prominent voices in sustainability and responsible design since the 1960’s is R. Buckminster Fuller.  Fuller pioneered in fields from architecture, and mathematics, to engineering and automobile design and only patented 12 designs allowing the vast majority of his work to be open-sourced and free to the public.

His life’s mission and philosophy was simple, “to make the world work for 100% of humanity, in the shortest possible time, through spontaneous cooperation without ecological offense or disadvantage of anyone.”

Even today, years after Fuller’s death his name is still the vanguard of the sustainable design community. The largest testament to his legacy is the R. Buckminster Fuller Institute and their annual international competition the Buckminster Fuller Design Challenge.

According to the institution’s website $100,000 is given “…to support the development and implementation of a strategy that has significant potential to solve humanity’s most pressing problems. Named “Socially-Responsible Design’s Highest Award” by Metropolis Magazine, it attracts bold, visionary, tangible initiatives focused on a well-defined need of critical importance. Winning solutions are regionally specific yet globally applicable and present a truly comprehensive, anticipatory, integrated approach to solving the world’s complex problems.”

In 2012 at an awards ceremony held here in NYC at Cooper Union The International Living Future Institute was awarded first prize for their “Living Building Challenge” initiative.  According to the institute’s website the Living building Challenge is:

-a PHILOSOPHY, ADVOCACY PLATFORM AND CERTIFICATION PROGRAM. Because it defines priorities on both a technical level and as a set of core values, it is engaging the broader building industry in the deep conversations required to truly understand how to solve problems rather than shift them.

-an EVOCATIVE GUIDE. By identifying an ideal and positioning that ideal as the indicator of success, the Challenge inspires project teams to reach decisions based on restorative principles instead of searching for ‘least common denominator’ solutions. This approach brings project teams closer to the objectives we are collectively working to achieve.

-a BEACON. With a goal to increase awareness, it is tackling critical environmental, social and economic problems, such as: the rise of persistent toxic chemicals; climate change; habitat loss; the collapse of domestic manufacturing; global trade imbalances; urban sprawl; and the lack of community distinctiveness.

-a ‘UNIFIED TOOL’. Addressing development at all scales, it can be equally applied to landscape and infrastructure projects; partial renovations and complete building renewals; new building construction; and neighborhood, campus and community design.

-a PERFORMANCE-BASED STANDARD. Decidedly not a checklist of best practices, the Challenge leads teams to embrace regional solutions and respond to a number of variables, including climate factors and cultural characteristics.


The challenge seeks to encourage designers to bridge the gap between the built environment and the surrounding ecosystems thus reinventing the typical developers’ business model and transforming the role of the building occupant from passive to more of an involved partnership with the earth and her resources.

For all manner of development the Living Building Principles are applicable, whether, “… a single building, a park, a college campus or even a complete neighborhood community, Living Building Challenge provides a framework for design, construction and the symbiotic relationship between people and all aspects of the built environment.”

You can download a complete document that outlines the specific requirements and benchmarks that must be met to receive certification HERE.

With its radical and rigorous requirements, this is more than “green washing”.  This is an excerpt from a statement released by The Fuller Institute after the award ceremony;

“The Living Building Challenge (LBC) is setting the standard for how to build in the 21st century by establishing the highest bar yet for environmental performance and ecological responsibility within the built environment … by “building a new model” and establishing new benchmarks for non-­‐toxic, net-­‐zero structures… The Living Building Challenge goes far beyond current best practices, reframing the relationship between the built and natural environments. LBC seeks to lead the charge toward a holistic standard that could yield an entirely new level of integration between building systems, transportation, technology, natural resources, and community. If widely adopted, this approach would significantly enhance the level of broad-­‐based social collaboration throughout the design and building process and beyond, dramatically reducing the destructiveness of current construction, boost the livability, health, and resilience of communities … the International Future Living Institute is charting a new and critically needed course in an industry that arguably remains one of the most consumptive … The LBC’s model of regenerative design in the built environment could provide a critical leverage point in the roadmap to a sustainable future and is an exemplary trim tab in its potential to catalyze innovation in such a high impact, high consumption industry…”

This is a valuable new asset and tool for the green building and green contracting community in NYC nd abroad in the fight for a greener and livable tomorrow.


https://ilbi.org/lbc  -living building challenge website


http://bfi.org/  -Buckminster-fuller institute website

Radical Sustainability and Passive House

Eco Brooklyn’s director, Gennaro Brooks-Church will be giving a presentation at New York’s 2012 Passive House Symposium. The topic of his presentation is “Radical Sustainability and Passive House.” The all day event is filled with interesting speakers and is a must for anyone interested in the worlds most cutting edge energy efficient building technique.

NEW YORK, NEW YORK – June 8 – The 2012 Passive House Symposium is a one day exploration of the many Passive House projects underway in the New York area.  With over forty Passive House buildings currently in the process of being designed and built, New York is a leader in the US for Passive House construction.  The symposium will demonstrate how architects, builders and owners are meeting the demanding Passive House standard, making a substantive contribution to New York’s climate change mitigation efforts.
Presentations will include 6 retrofit projects and 9 new building projects that span every phase of the process.  Rowhouses, multifamily, commerical and institutional buildings will be presented – located from eastern Long Island to New York City to Upstate New York.  Attendees will be eligible to earn 5.5 hours of Professional Education Credits for NY State.


Passive House Project, NYC

Tomas O’Leary, Director of the Passive House Academy, will provide an international context for New York’s efforts.   Tomas will describe how this global standard is evolving while growing exponentially.  He will show examples that include Brussels Belgium where Passive House will be required for all new and retrofit construction in 2015.


Certified Passive Houses:  Orient Point by Ryall Porter Sheridan Architects with Right Environments, and Omega Institute by North River Architecture + Planning will be presented.


Passive Passion, a 20 minute documentary on Passive House in the US, featuring New York practitioners and Dr. Wolfgag Feist, by Charlie Hoxie, will be viewed during the day.

Round Table Presentations: A variety of practitioners, each focusing on a different essential aspect of Passive House design and construction, will provide observations about the complexities and possibilities of this exciting new building standard for the New York area.

Saturday June 23, 2012 from 9:00 AM to 5:00 PM EDT

Sciame Auditorium
141 Convent Avenue
Bernard and Anne Spitzer School of Architecture
The City College of New York
New York, NY 10031


Passive House Institute LogoPassive House is an international building standard that affordably achieves the very highest levels of comfort and indoor air quality while reducing heating and cooling energy costs by up to 90%.  Passive House was formalized in Germany in the early 1990s by Dr. Wolfgang Feist and the Passive House Institute.   Passive House, with a proven track record of accurately predicting and delivering building performance, offers a clear, sustainable and affordable path for combating climate change.
NYPH logo

NY Passive House (NYPH) is an independent non-for-profit trade organization working to promote a healthy, comfortable and energy-efficient built environment through the promotion of the Passive House building standard.   Formed in 2010,  NYPH is supported by member dues and industry sponsors. NYPH facilitates the exchange of information and experiences, among practitioners of the Passive House building standard.
Affiliate of:
International Passive House Association

New York Passive House Windows

New York Passive House builders are all scrambling to find high quality windows that meed the strict PH air tightness and insulation standards. With the exception of a few Canadian windows there just aren’t any US windows that meet these standards.

Almost all good windows come from Europe and the challenge for New York green builders is to first find these companies and second figure out how to get the windows over the water.

Here is a great list of European High Performance Windows that a New York Passive House builder could consider. The list comes from BuidingGreen.com.

Eco Brooklyn’s last Passive House job used Austrian Reider windows, purchased from Thomas at Cembra.us. We were happy with them. They were very solid with a nice clean look.

Harlem Passive House
A Reider Door for the Manhattan Passive House we built


NJ Contractor Builds Passive House and Creates an Educational Video

Ed from NJ Renewable Energy made a great video about the construction of his passive house that you can view below.  It discusses the many benefits of building a Passive House, the amazing energy savings that are possible and the details behind how they built this specific one in New Jersey.

As a NY Passive House contractor we appreciate his hard work and dedication to sharing the information with the public.

Passive House Video from NJ Renewable Energy

New York Contractor Builds Passive House out of Salvaged Materials

Here is a short video we threw together of the Passive House renovation in Harlem. The video mostly discusses the budgeting of the project.

Now that the construction is for the most part done I think that our initial budget of $175/sq.ft is not sustainable. Of course it is great for the client in the long run. But as a company that practices the triple bottom line  – people, planet, profit – our budget did not  satisfy all three items.

Out of the three I can say without a doubt the planet was benefited by this job. We built a Passive House. We salvaged almost everything to build the house, creating a negative impact on the dump, meaning the house removed more garbage from the dump than it created.

Unfortunately the other two items – people and profit – did not get a fair deal. The workers were not paid enough, the client is not happy and the company did not make enough of a profit. Workers and company need to be taken care of in order for us to continue to make a meaningful impact on the world. Happy clients means more opportunities to build green.

The clients came to us with a very tight budget, $800,000, which is not enough for the scope of the complete gut rehab Passive House. $1,200,000 would have been more realistic.

But being realistic in not what got Eco Brooklyn to where it is now. You don’t start a cutting edge green building company because you are realistic. You start it because you are deeply idealistic and willing to sacrifice everything in the hope that it will make a difference to the world. There are huge risks to this.

So in that spirit we took on the job, our main goal to find a way to build a cutting edge green home on an affordable budget. We accomplished this, so from that point of view it was a great success.

But the clients are not happy and the company was hit hard financially. It may seem odd that the clients are not happy given they gained a $1 million plus house for $800K. We literally saved them hundreds of thousands of dollars all the while helping the environment.

But to achieve that we all had to make sacrifices. The main sacrifice was that as a company we could not afford to hire enough management. The job process was rocky. A green company needs to be even better organized than other companies because we are dealing with new cutting edge technologies with steep learning curves and we salvage materials thus we can’t tightly control the delivery time of materials.

This lack of management meant details were missed and client/contractor interaction was not as common. So even though behind the scenes we felt we were performing miracles to save the client money and add value to their home, the client did not see this.

The client simply felt they were paying what to them felt like a lot of money and we were not delivering as smoothly as they wanted. Because they don’t have a good grasp of what things cost it did not matter how many times we told them they would never be able to get this value elsewhere on their budget.

And when they did look elsewhere for comparison they saw crappy building with nice fixtures – the so called luxury condo that looks like a million dollars for the first couple years and costs a fortune to run. When you compare that to our building that does not look as fancy they felt shortchanged.

Never mind ours costs nothing to run and is built to last a hundred years. Those things are not as sexy as sparkling appliances and brand new moldings.

So we felt we were loosing our battle with the clients. It was very frustrating because we believe deeply that the building we made is decades ahead of any building built in the city today.

Core Values

In hindsight the main conflict was between the company’s and the client’s core values.

The company’s core value is clearly to put the benefit of the planet before anything else, with the understanding that by doing this we are benefiting ourselves as well. And in this case we did it to a fault (we should have done less for the planet and more for ourselves in order to continue strong in the long run).

But going balls out for the environment is both our strength and weakness.

The clients core value was to put their own benefit before anything else. This is not to say they did not care about Eco Brooklyn or the environment. But like most people, at the top of list is their own financial security, their family and their home, and when possible, but only when possible they consider the rest of the world.

I get that. I am a family man.

But I am also a green builder and sometimes things get complicated.

The problem was that we feel looking out for the environment is the best thing we can do for the client in the long run, even if it means less of a perfect construction process in the short run. The client however just wants a home for their family. Getting that done is challenge enough, never mind some idealistic and abstract global thinking.

Because of this we found ourselves at odds. For us if we could help the environment more we would. Even at the expense of short term discomforts and stress imposed by our main mistake – not budgeting for enough management and budgeting too much for the green building items – which arose from our over ambitious attempt to build a home for hundreds of thousands less than normally it would cost.

The client however found this inexcusable. If it is a choice to go some time without water in order to get gray water plumbing installed or skip the gray water and have water for their kids to take a bath they pick the later.

Unfortunately we were doing the building and not them. And we are very hard headed.

We picked to do the gray water, which delayed the job and meant the clients went without water for longer. Inexcusable in their eyes. Simply bad management. In our eyes it was a small sacrifice for something that will benefit the planet for many years to come…..which in turn benefits them.

It wasn’t like we expected the client to sacrifice alone. Eco Brooklyn always sacrificed first. If we found a way to satisfy the client and the environment at the cost of our profit then we made sure we did that first. Our priorities were planet, client then us.

Maybe we are wrong. Maybe that priority serves nobody. But I have this idea that we are connected and the ecology is in a lot worse shape than we are. Since we are ecology that needs to be dealt with first……?

But when the client is spending their hard earned money and the feel like the second fiddle, good will goes out the window fast and they stopped caring for us.

Towards the end of the job when we realized our ecological zeal had put our finances in tight stretches we got no mercy from the clients. In their memory was the lack of water and they made sure to withhold money accordingly. Water is just an example our of many conflicts of core values that arose.

What have I learned from this?

I can’t expect others to sacrifice for my cause. Next time I will only take on clients who can afford $1,200,000 and be done with it. They will get the job they were promised and I will be able to build houses that harm the environment a lot less.

This means that many people will be priced out and not benefit from Eco Brooklyn’s amazing green building.

But I have learned the hard way that when things get tight people hunker down and look out for themselves. It is about survival and humans can be the most brutal creatures on earth when they feel their own is being threatened.

I can’t put myself in that position of dealing with clients like that. Nor can I put the clients in that position. The clients of this house are scared. They feel we managed the job recklessly and this puts them at risk.

When they came to us they entrusted us as professionals to guide them in the building of a green home. They had no idea how much emphasis we put on green and at some point they wondered if we even cared about their home.

So in the future we won’t try the affordable green building thing because we can’t trust the client will be as willing as we are to build green. Instead we will charge. That way it won’t be a choice between having water on time or having a gray water system. We will have a budget to do both on time.

The clients of our current house had a tough time of it. I think with time they will forget the discomforts of the building process. As that fades they will see the value of the house. They might even be grateful towards us. But I doubt it.

Would I do it again? Yes. I think the struggle was worth the gain. It is an amazing house.

It is the first time in the history of building that a Passive House was built with such a high percentage of salvaged materials. It is revolutionary. And we did it not on some plot of land in Oregon but in one of the most expensive places to build on earth. For the price of a crap “luxury condo”!

But like all revolutions it was painful. And I am hurting more than anyone. I made sure I put my money where my mouth was. The clients probably will never understand that. But that is ok. I care about the house that we brought into existence.

When we are all dead that house will still be a wonderful home for families. That is a great gift. It is the least I can do for the planet and my fellow humans.

Here is the video that prompted this post.

Bringing Passivhaus to Harlem

Check out this great article about our Eco Brooklyn’s Passive House in Harlem.  GreenBuildingAdvisor.com, a great online source for building, designing, and remolding green homes, sent Richard Defendorf to our Harlem site to check out our work. Read his write-up of all the techniques we used to seal our passive house!


Eco Brooklyn’s Clay Wall Application

Eco Brooklyn’s Gennaro Brooks-Church discusses our clay wall application. Creating a better seal on bricks and more insulation, Eco Brooklyn applies clay to walls all over New York City. Most recently we applied clay in our Harlem Passive House and in the downstairs apartment in our Brooklyn Show House.

Check out this great video!

New Energy Efficient Products

Here is a cool article from GreenBuildingAdvisor.com. As a New York green contractor we are always looking for local green building materials, especially anything that relates to the super high efficient Passive House construction tools. These windows from Maine look really promising.

New Green Building Products

High-performance windows, doors, and tapes for your next superinsulated home


Image 1 of 9

This high-performance tilt/turn window was manufactured in Maine by Linwood Windows. The company uses European shaper blades to mill the Douglas fir frames. Most customers order the windows with triple glazing.



About every six months, I report on new products that catch my eye. This round-up features products from both sides of the Atlantic Ocean: high-performance windows from Maine, Ontario, and Lithuania; high-performance doors from Poland; and high-performance tapes from Switzerland.



Linwood Windows

Linwood Windows is a small window manufacturer in Tenants Harbor, Maine. Owned by Richard Cohen, the company makes European-style tilt/turn windows out of Douglas fir. All windows are custom made; the usual lead time is 12 to 14 weeks.

The fir frames are milled in Maine using European shaper blades. According to Cohen, windows using frames milled with similar shaper blades have met the strict PassivhausInstitut standard for certified Passivhaus windows.

Linwood Windows can be ordered with double, triple, or quadruple glazing. A wide variety of glazing options are possible, including triple glazing with a center-of-glass U-factor of 0.13.

Linwood’s triple-glazed tilt/turn windows cost between $120 and $160 per square foot.



Intus Windows

Intus Windows are manufactured in Lithuania and distributed by Intus Consulting in Washington, D.C. Intus sells both vinyl-framed and wood-framed windows. All Intus windows are tilt/turn style windows with triple weatherstripping. The company’s triple-glazed vinyl windows are some of the least expensive high-performance windows available in the U.S.


New Green Building Products — September 2010

New Green Building Products — March 2011

Passivhaus Windows

Choosing Triple-Glazed Windows




Fenestrations Plus
18 Penn Plaza, Suite 23A
Bangor, ME 04401
Distributor of Drewexim doors from Poland

Inline Fiberglass
30 Constellation Court
Toronto, Ontario M9W 1K1
Manufacturer of Eternity double-hung windows

Intus Windows
1042 Wisconsin Ave. NW, 2nd Floor
Washington, DC 20007
Distributor of Intus windows from Lithuania

Linwood Windows
P.O. Box 511
Tenants Harbor, ME 04860
Manufacturer of Passivhaus windows

Small Planet Workshop
4646 Oyster Bay Road NW
Olympia, WA 98502
Distributor of Siga tapes from Switzerland

Most of the windows that Intus sells in the U.S. have triple glazing with two low-e coatings and warm-edge spacers. (However, if the customer prefers, double glazing can also be ordered.) The windows are glazed at the Intus factory in Lithuania. Intus assembles its own insulated glazing units (IGUs), using Saint Gobain glass for Intus wood windows and Guardian glass for Intus vinyl windows. High-solar-gain triple glazing is an available option.

Intus vinyl windows use vinyl lineals (profiles) manufactured by Deceuninck Group (Belgium). None of Intus’s vinyl windows are Passivhaus-certified.

Intus sells two lines of vinyl windows; the less-expensive brand, Elite, costs about $35 to $38 a square foot for operable triple-glazed windows.

The higher-performing brand, Eforte, has vinyl frames with a lower U-factor than the Elite frames. The Eforte window accommodates glazing that ranges from 1 inch to 2.2 inches thick. Operable Eforte windows with triple glazing cost about $40 to $45 per square foot.

Intus wood-framed windows are called Premmier windows. Premmier windows all have exterior woodcladding. The less expensive Premmier windows, Premmier 78 windows, cost about $75 to $80 per square foot for operable windows with triple glazing and aluminum cladding.

The high-quality Premmier windows, Premmier Passiv, are certified by the Passivhaus Institut in Darmstadt, Germany. These Passivhaus-certified windows cost about $95 to $100 a square foot for triple-glazed operable windows. Passivhaus-certified windows include a layer of insulation between the wood frames and the exterior aluminum cladding.

According to Intus representative Aurimas Sabulis, the lead time for an Intus vinyl window is 10 weeks. Wood windows take a little longer — about 10 to 12 weeks. Intus windows do not have NFRC ratings at this time.

Intus also sells a line of aluminum windows with thermally broken frames.



Inline Windows makes triple-glazed double-hungs

Lots of manufacturers sell fiberglass-framed windows with triple glazing. Builders who need an operable window usually choose from just three style options: casement, awning, or tilt/turn. Although double-hung windows with triple glazing are available from a few manufacturers, most such windows have low-performance glazing and leak a lot of air.

Inline Fiberglass has just released a new double-hung fiberglass window, the Eternity. Unlike most double-hung windows, the Eternity can be ordered with triple glazing; not only that, but it actually has good performance specifications.

Making a triple-glazed double-hung window usually results in compromises, and Inline’s new window, dubbed the Eternity, is no exception. The biggest compromise: the window’s glazing pocket only allows glazing with a maximum thickness of 1 1/8 inch. That’s a little thin.

If you are using argon gas, the best triple glazing is 1 3/8 or 1 1/2 inch thick; such glazing won’t fit in the Eternity. If you want to include high-performance glazing in an Eternity window, you’ll need to order it with krypton, a more expensive gas than argon. (Thin krypton-filled IGUs perform better than thin argon-filled IGUs.)

Inline offers several glazing options. An Eternity window with triple glazing with two low-ecoatings and krypton gas has NFRC ratings of U-0.16 and a solar heat-gain coefficient (SHGC) of 0.18. If that dismally low SHGC depresses you — and it should — you can order Inline’s Synergy glass package. This option consists of triple glazing with 2 low-e coatings and krypton gas; the NFRC whole-window rating is U-0.17 and a SHGC of 0.46 — very respectable specs indeed.

When tested for air leakage according to ASTM E283-04 (Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen), an Eternity window with an area of 17.2 square feet had infiltration and exfiltration results of 0.07 cfm. This is an excellent result for a double-hung window.



Drewexim doors

By now, most builders of energy-efficient homes have settled on their preferred window supplier. Buyers can select a U.S.-made triple-glazed wood window, a Canadian-made fiberglass-framed window, or a European-made Passivhaus window. When it comes to entry doors, however, there have been few choices available.

American entry doors are thin flat slabs that close against a single stop, and many entry door brands include just one layer of weatherstripping. European doors are built differently. For one thing, they are thicker, which means they feel more solid and often have a higher R-value. They also have rabbeted edges that step down: the door’s perimeter has rabbets that mate with a rabbeted jamb equipped with two or three layers of weatherstripping.

Almost everyone agrees that German doors are built to high quality standards than typical U.S. doors. The main drawback to German doors is that they are very expensive. However, U.S. builders who are frustrated by the low performance of U.S. doors and the high price of German doors now have a third option: Polish doors.

Drewexim doors are manufactured in Koszalin, Poland. One U.S. importer and distributor of Drewexim doors is Fenestrations Plus of Bangor, Maine. According to owner Nate Campbell, the territory served by Fenestrations Plus includes most of New England.

Drewexim doors are available in pine, meranti, oak, and mahogany. If the door will be painted, finger-jointed pine is available at a lower price than stain-grade pine. Aluminum-clad doors are also available. Door panels are manufactured with a core of foam insulation sandwiched between two layers of veneer.

Drewexim doors can be ordered with either double or triple glazing. The standard door thickness is 68 mm (about 2 5/8 inch), significantly thicker than standard U.S. doors (1 3/4 inch). Drewexim also offers extra-thick 88 mm (3 7/16 inch) doors.

A pine Drewexim entry door with a triple-glazed light costs between $1,800 and $2,300; more exotic wood species cost more. The necessary lead time is at least 12 weeks; delivery may be delayed by the need to fill a container before a shipment can be scheduled.

One U.S. purchaser of a Drewexim door is architect Jesse Thompson of Portland, Maine. Thompson described some of the features of his entry door, pictured below: “This is a 68 mm standard solid stained pine door (not the thermally broken 88 mm style). The inset panel is a laminated insulated wood panel, and the light is triple-glazed. Hoppe hardware is standard and included.

“The hinges are adjustable: an Allen key inserts into the drilled holes, allowing the door panel to be raised, tilted, and lowered to adjust inside the frame easily through the years.

“The door has a European ‘threshold.’ It’s not a full width and depth sill; it’s more like an extrusion rabbeted into the bottom of the door panel that holds the jambs together. It’s designed to allow the door unit to be placed on top of a finish floor that runs continuously under the door — if you’re in a 300 year old stone building, for example — without having to cut a slot lower than the door unit like U.S. doors. We installed it by setting the door unit on a strip of Advantech the same height as the finish floor to come, so we could later slide the finish floor under from one side, and a trim sill under from the other side. U.S. doors are designed to sit on the subfloor; these aren’t. That was confusing at first.”

Minor installation confusions aside, Thompson is pleased with the value offered by Drewexim: high quality at a reasonable price.



Siga tapes

I first mentioned Siga tapes over a year ago, in my blog titled One Air Barrier or Two? Since that article was written, an increasing number of U.S. builders have recognized the advantages of high-quality Siga tapes.

Siga is a Swiss company that manufactures a complete line of air-sealing tapes for builders. The tapes are imported and distributed by Albert Rooks of Small Planet Workshop in Olympia, Washington.

All Siga tapes have a tenacious adhesive. However, these high quality tapes aren’t cheap: expect to pay from $30 to $59 a roll for narrow tape, and even more for wide tape.

For taping the seams of an interior air barrier, Rooks recommends Rissan 60 tape. (The number refers to the tape’s width in millimeters; 60 mm = 2.36 inches.) One roll containing 82 feet of tape costs about $33; the price drops to about $30 a roll when you buy 10 rolls.

For taping the seams of exterior sheathing, Rooks recommends Wigluv 60 tape. Wigluv tape works well on unprimed OSB or plywood; concrete, however, needs to be primed. (Rooks suggests that the seam between a concrete foundation and the mudsill or the bottom of the wall sheathing can be bridged with Wigluv tape.) One roll containing 131 feet of tape costs about $59; the price drops to about $53 a roll when you buy 10 rolls.

Both Rissan and Wigluv tape can also be ordered in wider versions; of course, the wider the tape, the higher the price. If you need primer for a concrete foundation that will receive Wigluv tape, Rooks sells that as well. Siga Dockskin primer costs about $35 a can.



Last week’s blog: “Spray Foam Jobs With Lingering Odor Problems.”




Triple Pane Windows Arrive to EcoBrooklyn Passive House, Harlem

We just received our triple pane windows from Europe to our Passive House site in Harlem. The windows will help the brownstone achieve its necessary air tight specs and save up to 90% in energy costs compared to an ordinary building of the same size.
If you enjoy the video, please give us a “Like” on YouTube, and feel free to comment!

Triple Pane Windows arrive to Harlem Passive House Site

The windows we ordered finally arrived to our Harlem Passive House. They’re not your typical windows though by any means, and unfortunately we couldn’t get them USA made. These are triple pane windows. They’re pretty heavy compared to a typical window of the same size, and a heck of a lot more expensive. As a New York green contractor we are very conscious of the well-being of our environment, so we salvage things – wood, insulation, even masonry products to name just a few. But when it comes to windows, we get those brand new and spend a large lump of our budget on them. But they will surely play their crucial role in helping the Harlem brownstone meet its stringent Passive House specs. And within just a few years these windows will begin to make sense on a business level. And as for the reduction in energy use, helping to reduce our carbon footprint, this investment is a no-brainer. An absolute no-brainer.

Presenting Triple Pane Window Technology to EcoBrooklyn, Passive House contractor
Triple Pane Windows arrive to Harlem site, EcoBrooklyn, Passive House Contractor


Passive House Web Site

Here is a cool web site about all things Passive House, aptly called, International Passive House Magazine, or IPHM. It is run by Tamas Banki. Based in Hungary he is doing a great job pulling together all the PH info from around the world.

As a Passive House builder in New York I found the site interesting because it gave me a global perspective I hadn’t seen before. I’m familiar with the Irish PH community as well as the very large German and Austrian PH community.

What is cool about the IPHM is that it offers an “outsiders” perspective of the global PH movement. From my very insular NY Passive House perspective I find that perspective refreshing and informative.

I discovered the site when our very own NY PH dude Gregory Duncan was featured in an article on the site. Go Greg!

ERV – New York Passive House Discussion

Here is a discussion between myself and other Passive House people regarding what ventilation system to use in the New York Passive house Eco Brooklyn is building. I originally got a bid for an ERV from Barry Stephens at Zehnder, which I thought was expensive. That prompted me to ask around for other options. The discussion that followed gives good insight into what is available (not much) and how to lower costs.


Barry Stephens

The Harlem project is very impressive, especially the use of totally re-cycled materials.

As per our review of the project, here is a quote for the three units. I have broken the quote out in to the three systems, and the total for all three comes to $14,613.60.

Thanks for working with us, and I look forward to seeing this project completed.


Gennaro Brooks-Church

My ERV budget including labor and profit is $15,000. So a material cost for $14,600 isn’t going to work. Maybe I made a mistake or maybe the prices went up since last time.
I think the Zehnder prices are not sustainable. The Zehnder ERV is twice the cost of all the building’s heating and cooling and half the cost of the entire door and window budget. Maybe it is the Euro conversion or the over engineering of the product but the price is just not justifiable given the technology and materials involved to make an ERV. I can’t recommend your product as a green solution because it is inaccessible to most of the population.

I am going to speak with Floris this week about other ERV makers as well as looking into just buying the units from Zehnder and sourcing all the accessories elsewhere. What are your suggestions on just buying the units? Labor is much cheaper than the Zehnder accessories so maybe I can reduce costs there?


Barry Stephens

Per our previous discussions, I understand your position on the cost of our systems. And I would like to point out a couple of important points to consider:

1) European ventilation systems represent a paradigm shift in thinking with regards to HVAC design and budgeting. By combining tight, well insulated envelopes with high performance heat recovery, you are able to significantly reduce your heating/cooling loads, and the cost for those systems. Which is the Passive House model.

I had a conversation with Katrin Klingenberg from PHIUS at the PHI conference in Dresden, Germany last year. She wanted us to bring in and distribute the Paul by Zehnder H/ERVs, which are almost twice the cost of the ComfoAir units. I told her that I didn’t think that we could sell them at the high prices we would need to charge, and she explained that by using a Paul unit and applying the numbers to the PHPP, a builder could potentially reduce the insulation of the entire envelope by two or three inches, or save significantly in aspects of the design.

2) I believe that our H/ERVs are a good value, based on efficiency, quiet operation, and quality and dependability. We also offer more functionality and controls than alternative brands. The Euro/Dollar exchange does increase the price modestly, and so we are what we are in that regard.

3) Our ducting systems are indeed over-engineered in some respects. They were designed for use in concrete, as well as wood framing, etc. We are aware of this, and we are developing alternative components that will reduce the cost of a system. In some cases these are plastic components, and in some cases we may manufacture components in the States to reduce costs. We are looking at these options now.

The fact that Habitat for Humanity is adopting PH as an alternative standard in some of their regions, and using our H/ERVs in these projects is testament to the viability of this model for affordable projects. We are working with affordable housing projects in CA and OR as well, and they understand that although our piece is more costly than traditional heat recovery systems, taken as a integral component of the whole-house-system approach, we are worth it in the end.

Additionally, our ducting systems have allowed for installation that is consistent with proper air distribution schemes in retrofits, and for installation in half the time as conventional ducting. I discussed this with Charlie, who agreed that you had tackled a most difficult first project at your home.

Lastly, you may have had the impression on the pricing based on the 22 2nd St project, on which we provided a personal project discount.

We have completed a number of projects in the NYC area, and to date the results are positive. From my discussions with the contractors that have installed these systems, we have been considered a good value. I hope that you will consider the above points as you go forward on this and other projects. I am confident that you and your clients will be well served by including Zehnder.


Gennaro Brooks-Church

Thanks for the email. I have heard these points before. I still think
Zehnder is expensive. And my budget is fixed. So it is frustrating.
Maybe Floris and I can find a way to reduce material cost by sourcing
from other distributors and just buying the Zehnder units. Also
swtiching from ERV to HRV would save some money.


Gennaro Brooks-Church

Hello Passive House friends, I just got the ERV quote back from Zehnder for the Harlem Passive
House I am building and the high price knocked me off my chair.
Totally not sustainable.

So…. do any of you have alternative manufacturer suggestions?

Or maybe you can suggest creative ways of just buying the Zehnder unit
and sourcing the accessories from another company?


Dave Solaz

I just finished up a product development grant application to the CT Clean Energy Fund and I had reason to do some research on HRVs and ERVs for small buildings. I was drawn to the Venmar Constructo Series Product because it can be transformed from an Energy Recovery Ventilator (ERV) to a Heat Recovery Ventilator (HRV), simply by changing its core (either of which can be purchased separately). This gives you the ability to reject humidity in both the summer and winter months (if you have good reason to do, as I did).


Floris Buisman

Venmar EKO has efficient fans, so does stay below the PHI recommended 0.45 W/m3/hr, but their heat recovery efficiency is just not there – HVI test show 83%, which means for modelling (as PHI testing is much stricter) we would have to deduct 12%, so 71%, which is below the 75% minimum for PH certification.


Raymond Evangelista

Do you know what model you got a quote for? I know they have some new
models that are a little higher than the models we purchased. Was the
price higher then when you purchased your unit?

The Zehnder unit has the ability to change the core from erv to hrv too. I
was told a 2nd core would cost about $800 – $900.

When I looked into the units I did a lot of homework. I found that Zehnder
made the best product. I even visited two people that manufacture the
units in the northeast. The products had a simple design, but the
efficiency numbers were close to 60-70 efficiency. Needless to say that
falls short of our goal. One unit was a casing around the core. If the
core went bad you needed to replace the while unit.


Gennaro Brooks-Church

I was quoted for two ComfoAir 200 ERV and one ComfoAir 350 ERV. Total $15k.
What company did you visit in the Northeast? Not that I guess it
maters if they are only 60-70% efficient.


Raymond Evangelista

That does sound very high. I have the 350 and everything I purchased came
out to 10-11K.

I don’t remember the one company. The unit was junk and I wouldn’t wish it
on my worst enemy. The 2nd unit was made by building performance equipment
out of Hillsdale NJ. This is the unit where the core and the casing are
one. They claim to be at 85% efficiency, but that was pretty far from what
I noted when I was there. The outside temp was about 40 and the indoor
temp was 70. The air coming out of the unit was about 60. Needless to say
that isn’t 85%. The unit also needs two in line bathroom fans to move the
intake and exhaust air. Needless to say that also impacts the efficiency
of the units. That being said I think the units would be great for
non-PHPP projects. They are simple and very easy to troubleshoot being the
only moving parts are the fans. The units run about $2000 and you would
need two for your project. Unfortunately they don’t have a duct solution.
The last time I spoke to them they were seriously looking at the Zehnder
duct system.


Floris Buisman

We could switch to an HRV and save $500. Humidity wise the house should be fine in the winter, as the apartments are small and thus the people produce sufficient humidity to keep it comfortable in the winter. In the summer not having an ERV would be a small energy penalty for the additional dehumiditication that the unit needs to do, but nothing major.

We can then use off the shelve parts for exhaust and supply boxes, grillers and diffusers. This should cost less $75 per exhaust or supply point.


Jesse Thompson

We’ve used the Comfo 350 with sheet metal ductwork to save costs, still ends up $5 – $6k installed in the end. We’ve also built recently with the Venmar EKO (low watts, decent efficiency), but it still lists at $1,500 (less than the $2,200 for the Zehnder..) but is a lot louder than the Zehnder.

The fancy tubular ductwork and the super heavy gauge swiss register boxes add a lot of cost, a complete Zehnder system can get very expensive. A Zehnder box + standard US ductwork should only be $1,500 more max, if you compare to $600 Fantech HRVs that get installed for $4k or so.

The sad part is the Zehnder is the only unit I would really consider “high-end” that we’ve been around because the others are so loud, especially when they switch into defrost mode on high speed. This includes Venmar, Lifebreath, Fantech, etc. The average USA unit isn’t a very nice piece of equipment, sadly.

There’s a reason HRVs get disconnected so much I’ve realized, most are too noisy to live with in a small house.


Kristen Simmons

Thanks for splitting that out. I’m about to get 2 Zehnder units. Nothing’s been priced yet, but I was beginning to get disturbed. I will be going for the comfotubes, as it is a retrofit, but I expect that the added equipment costs will be off-set by significantly reduced installation costs. Might just do it myself, as I’ve heard that it’s incredibly easy.


Jesse Thompson

Honestly, it feels like back when the only way to get a fancy luxury car was to buy German, but once all the other manufacturers realized there was a market for high end product they started producing it very quickly, and now all nice cars are equally quiet and well built.

Early adopter’s peril.


Philippe Campus

From what I just read, this may not provide much help at this point, but here is a document which reviews most (all?) the HRV/ERV units that were available in the US a little while back.

It shows 2 things: It is almost impossible to know all the ERV models which are out there, and what their rated performance is, behind the marketing hype. Mark Rosenbaum refered to this document in his mechanical systems presentation (phase II). Digging through this list, there may be a more affordable ERV which comes close enough, if there is a bit of leeway in your PHPP numbers; but nothing will compare with Zehnder, or we would know about it already.


Lois Arena

Have you guys used the UltimateAir RecoupAerator and not liked it? Too loud? Not large enough?

It has the highest efficiency in the US that is UL approved anyway. Around $1500 for the unit. No fancy ductwork. They have someone on staff who specializes in Passive House applications.

Has anyone tried the mufflers that Katrin suggested?


Lois Arena

Here’s a comparison of ERV’s done by UltimateAir


Kristen Simmons

The UltimateAir is the only other unit I’ve been considering. It was used on a DER project up here. The builder (paul eldrenkamp) has been doing monitoring. I’ll ask him is he has any feedback from the occupants. I’ll also share the question with the PH-Boston group, to see if they have any end user feed back. It’s a small group, but with deep experience. It’d be interesting to compare published dBA with user experiencem


Gennaro Brooks-Church

From what I can tell the best option right now is to go with the Zehnder box, maybe the cheaper HRV over the ERV if your climate isn’t too humid in the summer… and then all the rest you buy locally. For example Zehnder sells a sound muffler and you need two. Once you get all the adons for that it is almost $1000 just for the mufflers! But you can buy two HVAC duct mufflers for $100 total. I’m sure Zehnder makes a fine muffler but is it 10X finer?

Now whether I can get away with an HRV in NYC is another question. It gets oppressively humid in the summer.


Barry Stephens

Your approach is perfectly fine, and we have had a few projects go that route. A couple of considerations:

1) If you use metal ducting, you may want to consider silencers only.

2) I would use ERVs, based on experience in NYC to date. We have one project with Jeremy Shannon at Prospect Architecture where he used HRVs, and the homeowners ended up upgrading the units to ERVs. This was due to high humidity levels starting this spring in the house in Brooklyn, which is fairly close to your house, on 3rd St. Virtually every other NYC project has used ERVs. Switching to CA 350s is totally fine, as long as you can accommodate the difference at installation.

As I said, I hope that we will have a more cost-effective solution in the near future, and that you will be able to justify using the full system. At the moment, I have what I have to work with and will do what I can to accommodate your projects.


Jesse Thompson

From everything I’ve seen, your AC will be doing the dehumidifying work in your NYC summers, certainly not your ERV / HRV. An ERV reduces some of the incoming moisture in your ventilation air, but you’re still bringing it in to be dealt with, it’s a minor issue.

Anyone who opens their windows occasionally in the summer time will add moisture to a house that can only be dealt with with a compressor, your ERV will reduce the impact of wet ventilation air, but it can’t help with a humid house.


Nicholas Lehto

I just installed the recouaerator in two homes and I’m been pretty happy with it. It isn’t a super high end piece (ie German quality), but if it gets the efficiency they claim and it doesn’t break, then who really cares how pretty it is? Both customers commented on how quiet the units are and wondered if they were even running. This could have a lot to do with the fact that they are installed in conditioned basements away from the bedrooms, but even when you are standing right next to the unit its not overly loud. Its definitely quieter than the Venmar eko 1.5 I installed in a home last year. The only real complaint you can have with it is that you need to make sure that the incoming air is above 18f to prevent the core from freezing. If the budget doesn’t allow for a brine heat exchanger or earth tube, then you have to go with an electrical element to pre warm the air. It only uses enough energy to bring the air up to 18f ., At 70cfm it uses 44w @ 10f, 265w @ 0f, and 487w @ -10f. We aren’t talking huge number, but every watt is a watt.

Enough with the HRV’s/ ERV’s, what we really need is this: http://www.nilan.dk/en-GB/Frontpage/Solutions/Domestic-solutions/Total-solutions/Compact-P.aspx. Its been in the University of Darmstadt’s winning solar decathlon home the last two years. I just got back from visiting family in Finland and while I was there I toured a Passive House that had this unit (try taking any house you’ve designed in PHPP and stick it in Helsinki, its VERY tough to meet the standard there) . The house was built by the owner of a company that manufactures rigid foam, so he had the means to experiment with some pretty cool stuff. I can share pics if anyone is interested.


Gennaro Brooks-Church

Those wunder Nilans are how much? Around $18,000?
Amazing stuff.


Floris Buisman

I have an ultimateair, it is pretty load and changing the energy exchange pies is not simple enough for a regular home-owner


Barry Stephens

Jesse makes a valid point, and I would like to respond. I spent last week in NYC (Tuesday, including visit to your project), WV and VA visiting projects. Virtually every one of those chose ERVs. A couple of those chose HRVs originally, and swapped up to ERVs. I left with 9 ERV cores, and came back with 9 HRV cores. This is due to actual performance with units in the field.

One interesting discussion we are having right now is the effect of the combination of PH level envelopes and high performance H/ERVs on the performance of newer heat pumps. Specifically, we are looking at the possibility that heat pumps may be short cycling in cooling mode, resulting in inadequate dehumidification. There also may be a tendency to oversize the heat pumps, due to skepticism by the contractors with regards to PH loads. I spoke with Floris about this possible issue, and he was aware of the focus of the manufacturers to reach high SEER ratings, and the possibility that they are compromising on the dehumidification factor to reach high SEER numbers. Add short cycling to that, and you may find inadequate dehumidification using an HRV.

In consideration of that, it is very beneficial to use an ERV to significantly reduce the humidity of incoming air in humid climates. With 60-65% enthalpy efficiency, our ERVs will have a big impact on both humidity, and cooling efficiency during high RH periods.

To put the cost factor in perspective, you can consider this:

Price of fuel efficient cars –

Chevy Aveo – $12,000
Kia Forte – $15,000
Ford Fiesta – $13,200
Toyota Prius- $23,500
Civic Hybrid- $24,000

I guess that we are the Prius in the H/ERV market, and I am sure that we will see manufacturers follow suit in pursuing higher efficiency, quiet operation and reliability. But based on my knowledge of the engineering, manufacturing processes and economies of scale that we have, I would predict that our competitors’ pricing will have to rise to meet ours, or they will fall short of meeting the performance goals they set out to achieve.

Keep up the conversation. I appreciate the feedback, and share your thoughts with my colleagues in Europe. I think that you will see that we are listening, and we will develop products and systems to bring down the cost of systems.


Floris Buisman

As Jesse and I mention, the benefit of the ERV is small in the summer – and the mini split has the capacity to take care of the heat/humidity (I know, it will result in a slightly higher electric bill). In the winter there is not much difference, although the ERV would allow the comfortable humidity levels to be preserved. With the small living spaces per person mean that the human activities (showering, cooking, breathing) per SF]]square foot should add enough humidity to keep the indoor RH around 30-45% (unless residents go on vacation for long periods of time and thus do not add humidity to the building).

There was an issue at a larger house in NY that had an HRV. There where 3 people living in over 2,000 SF house. Running the HRVs in the winter did eventually dry out the house. In that case an ERV is worth it. There is always an option for the owners to swap out the core to an ERV if they chose to do so at a later time.

It does save money on your construction budget, so you need to make the decision.


Gennaro Brooks-Church

From what you all say I would conclude the following for a NY brownstone:
if the HVAC is sized correctly (which it is) then it will remove humidity in the summer
if the apartments are small (which they are) then human activity will provide humidity in the winter

The big question is how much added benefit the ERV will give compared to the extra cost if the budget is tight.
It is compelling that you just changed out 9 cores to ERV, although I don’t know the details of each home and how they compare to Harlem.


Jesse Thompson

I would add one note, whether or not ERVs can keep humidity levels low in a building is completely dependent on occupant behavior. It a building is sealed up constantly and operates in a steady state, I would agree with below.

If, on the other hand, people use the building as is common practice in NYC in my experience (leave windows open until it becomes uncomfortable inside, then close them to try and gain comfort, but indoor air is now 80+ F w/ 80% humidity), I can’t see the ERV doing much to add comfort. It won’t make things even worse, but the scale feels off in terms of humidity management.

We do need dehumidification biased heat pumps, but I can’t imagine that’s on the radar of the manufacturers yet. Building Science pushes explicitly for stand-alone dehumidifiers in low-energy buildings (but higher energy than a PH…) even though they add heat to the building as they move out moisture.

Some of their reports:



Gennaro Brooks-Church

Jesse you bring up an important point: the massive importance of not having the unit running when windows are open. I turn off my unit when windows are open, which has been part of almost every day since this winter. but I am a contractor.
So far the conversation haso been constantly running units….aren’t we missing something…


Jesse Thompson

My HRV runs when my windows are open. I still use less than 350 kWH for a family of four. That’s what efficient equipment is for…


Gennaro Brooks-Church

350kWH is great! For an American…..:)


Jesse Thompson

Only 240 last month, and that’s with all electric cooking and dryer…
I have clients in the 950+ range. Very common.

No cable box, no DVR, all LED and CFL. Couple computers on all the time, but low power computers. No furnace fans, boiler fans, have direct vent modern gas boiler, doesn’t use much juice. No AC.


Gennaro Brooks-Church

After looking into it I have decided that if I buy the ComfoAir units from Zehnder and all the other items from other manufacturers that I can make it work within the budget we have. I would also like to use only the 350 over the smaller 200 which would save money. We could further cut costs by using an HRV over an ERV, given we will have small apartments that provide user generated humidity in the winter and will have correctly sized mini-splits in the summer that will remove humidity.


Passive House Principles, Insulation and Airtightness

Here are two useful videos on Passive House principles, insulation and air tightness. Eco Brooklyn is a New York Passive House builder and we are committed to spreading Passive House information. It is good stuff, especially when combined with green building strategies of recycling and salvage.

In the video you well see Tomas O’leary, our main man from Ireland.

Great Passive House Info

Here is an excellent pdf on Passive House. It shows the construction methods and results of a group of Passive House buildings in Hannover, Germany, giving a great insight into how Passive House works.


As Passive House builders in New York this information is invaluable to us. In NY we are definitely experimenting with a different geographical environment but the core Passive House technique stays the same no matter where you build.

Compared to most German Passive Houses, a New York Passive House has to contend with larger temperature swings between summer and winter, as well as a higher humidity level in the summer.

But so far the success rate of Passive House building in New York and Brooklyn has been really high. The biggest issue is air sealing the hundred year old brownstone walls, which are full of cracks and holes. Insulating is pretty easy and it is amazing how little is actually needed, due mostly to the brownstones having two party walls on each side that are heated by your neighbors.

The main challenge is finding a good ERV or HRV. The good ones like Zehnder are  unsustainably expensive. And the cheaper ones lack some key functions.

But these are small challenges given the massive benefits of a well built NY Passive House. Our current Passive House brownstone in Harlem in the mechanical stage right now. We are getting the ERV set up. We are also doing the mini-splits which will heat and cool the floors.

Some things still in the air are the composting toilets and gray water. This has nothing to do with Passive House construction but everything to do with green building. We just are not sure if we can do it with the DOB approval so it is on hold until we meet with them.

Harlem Passive House Update

We have been working on the first slated Passive House in Harlem, Manhattan, for a couple months now. It was a complete burnt out shell when we started. Since then we have cleaned it out, put in floors, stairs and a roof. Check out the pics below.


In this Passive House project we are exploring ways to incorporate fully recycled materials as well as the standard PH techniques. So far we have had good results.

We built a wall from the cellar to the roof  against the front and back exterior brick walls out of salvaged insulation. To do this we removed the joists nearest the exterior walls. The end result is one unbroken insulated wall on the front and back exterior walls (the ones that get hot and cold).


Insulation on and between the framing:


Showing the space between the floor and the outside wall (which we will fill in later):


We then mortared the joists in place and then sealed around them with felt tape and mortar. This is to stop any possible air leaking in around the joists.


Felt tape:


More felt tape:


Felt tape covered with plaster:


Energy Efficient Front Doors

It is striking that despite the many green building going on in the US that there still remains some blaring gaps in our knowledge and available products.

I encountered another of these gaps recently in my search for a good front door for a Brooklyn Passive House style brownstone. I was looking for something super energy efficient. The door needed to be mostly glass, fiberglass frame, triple pane, low e, with a short turnaround time. Money is not the main issue because I expect to pay for this quality.

First I put a shout out to my Passive House lists and got very little. Then I did my own research and got very little. This is what I did get.


The least expensive high quality door with good thermal performance one Passive House architect used lately is a DrewExim from Poland. German quality, but eastern european pricing. Full Sikkens color range, all the typical Euro species (pine, larch, meranti, etc)

A triple glazed, solid wood frame, foam / wood inset panel with Hoppe hardware is under $2k. They make a wood / foam sandwich jamb and stile as well, they call it their “Passiv” door, but I don’t believe it’s PHI certified. It is certainly Passive House inspired and the quality is really good.

Prepare for a long lead time, 3 months is very possible.  So for my needs it won’t work on this job….

Max Value Doors

I came across this triple glazed fiberglass door called MaxGreen by Max Value Doors from China. The door looks good but I’m not ready to jump without seeing it or getting some colleague endorsements.


A colleague in Portland built a Passive House and all their exterior doors were Therma-Tru fiberglass “Smooth-Star” units, fitted with Hoppe multi-point latching hardware, and a custom sill that permitted a continuous gasket around the perimeter rather than a traditional sweep.

These units fit the budget on his project (no German imports!) and performed admirably during their blower door test (0.2 ACH 50). Very promising! I am not sure about the lead time for those custom items. It could be a couple months.


For generic off the shelf stuff I know one builder likes Pella flush metal. They have about R10. Their seals are the issue, though. They don’t always keep a great seal and other more energy efficient door distributors will love to point this out to you. But for convenience you can’t beat them. They are stocked all over the place and lead times are good.


You can also take a good door, say a fiberglass one with good seals, and cut-in a window with 3x glazing. It may feel sacriligious to cut a perfectly good door and you are opening yourself up to making a door that looks DIY (not good), but if done right you can have a very good professional looking door on your hands, provided your hands have the professional skills to do it of course.

I know some green builders who have done this for their own homes and are happy with the results. It is basically what Serious Windows below does. I like this approach because it takes the priestly control from the manufacturers. As consumers there are places where the manufacturer calls the shots, and windows and doors are one of them. They are the priests who control our access to the divine secrets of door and window making.

But making your own windows or doors is not impossible. The technology is rudimentary, involving an understanding of sealing and thermal bridges, and the materials are readily available as long as you stay away from trying to make your own fiberglass forms. If you know what you are doing you will probably have better quality control and definitely better prices than the manufacturers. But of course your time is also valuable so how long it takes you is probably the main consideration.


Innotech was installed in a Passive House retrofit in Portland, OR. I don’t have anything qualitative to say about it, other than it was deemed sufficient for a Passive House job with Portland weather. Might not be good enough for Brooklyn weather but definitely worth looking into.

Serious Materials

Serious Materials is mainly known for their Uber fancy windows and equally fancy prices. They have very good product, maybe the best in North America, although some are so energy efficient that they loose in visible light transmittance. A house with Serious Windows can feel darker than others, like it is wearing sun glasses, if you don’t get the balance right.

Serious doesn’t do doors but they buy fiberglass doors from several manufacturers and put their own glazing in them. Since I’m looking for a door with a good window in it this is interesting to me. I also would rather do it than I try the DIY method myself.

Triple pane windows are heavy. To get around this they use heat mirror (some fancy term), so the extra thickness and weight of triple pane glass is not an issue.

They buy doors from Thermatru, CDS/Trinity/Signamark, or Fibercraft. Out of this list I hear mixed results.  Thermatru is pretty good.  I hear Signamark doors suck pretty bad.  They don’t have triple point latches available, and the air sealing is bad.  Fibercraft are supposed to be very good, but they are twice as expensive as Thermatru. Their own web site sucks though.

The one catch, and it is pretty huge, is that they only retrofit patio doors. The Serious rep is the first to admit that a patio door is not built to withstand the higher traffic of a front door. So despite the them originally being my first choice I had to nix them because I want a front door that can withstand groups of people and wild eyed kids going to and fro.


As far as I know Thermotech is one of the many companies that started with windows and then did doors. I don’t know much about this company apart that it is Canadian and as such has higher energy efficiency standards. A lot of these companies on this list are Canadian. I didn’t go over the water to Europe where you can get lots of great doors because I want to encourage the local market.


I got a bid for a Jeld-Wen aluminum clad wood  full view door with triple glazing and multipoint lock system, for just under $1200. They are easy to get at your local Lowes and the lead time is acceptable.

Regrettably, performance data is a carefully maintained secret with Jeld Wen, and the spec sheet provided by the vendor shows values that jump around irrationally, from config to config.  Nor do they indicate whether the
posted U values are for glazing or whole units.  It is not clear whether the triple glazing is actually three isolated windows or two with a decorative pane in between.

I’m therefore inclined to make the more cynical assumption that it is for glazing only, and use the lowest U’s for comparison–even so, they take you well below 0.30 which isn’t Ubber Passive House standards but still great –and the price is compelling…


I’ll be updating this post as things develop but for for now I am looking at at Therma-Tru and Innotech. If they have a long lead time I may consider Jeld-Wen just for price and speed considerations.

HRV / ERV Efficiency

With our new Passive House building standard a key component of our green brownstone renovations are the ERV or HRV, or Energy Recovery Ventilator and Heat Recovery Ventilator.

Both units perform the same task of clearing the house of stale air and providing it with fresh air from the outside. In a “normal” brownstone this task happens naturally through all the cracks in the house. But with a green brownstone we have sealed all those cracks up in order to reduce the heat loss. So we need to compensate for the tight envelope by helping the house breathe.

Once the ERV is a key feature in any green brownstone renovation it becomes important what the energy efficiency of the unit is since it will be running a lot. There are several on the market. Here we have listed the best HRV / ERV’s for fan energy in the range of .5W/cfm, meaning they use half a Watt of electricity for every cubic foot of air moved each minute.

At this point in the technology 0.5W/cfm is considered a good industry standard.

The units that meet this standard are:
Sterling is $1900 list $1300 contractor cost plus shipping & tax with no accessories.
It has the highest heat transfer (because it is an ERV and recovers the latent energy from the moisture in the air).
It’s electrical efficiency is great on low speed, but sucks on high (over 1W/cfm).
The biggest problem is it’s a rotary wheel, so there is a high likelihood of failure. I have heard of it failing. And the wheel also has higher maintenance (maybe twice a year checks). Despite this I still have a soft spot for the Ultimate Air.

Some think this is the only unit that meets Passive House Standards, but they are confusing getting a product “certified” rather than the building as a whole (no HRV / ERV Required). You can install a unit that is PH certified and still not get your house certified due to other problems. But I think in a house that tight it’s a must have.

Sterling Ultimate Air Recouperator needs to be on low speed only.  It’s electrical efficiency is great on low speed, but sucks on high (over 1W/cfm).  The sterling has good specs and is very popular in Passive House building, and it costs similar to the Eko. So you have to see if spending $1000-1500 extra over others to save around 100-200 kWh/yr fits the project needs. It has the highest heat transfer (because it is an ERV and recovers the latent energy from the moisture in the air) and that is one of its pluses.

Lifebreath 155 & 195 ECM 2 speed (5 ranges to choose from)
Fantech SHV704 & VHR704, single speed
Venmar Eco 1.5 2 speed (5 ranges to choose from), around $1400
vanEE 90H-V single speed
Partners Choice HRV-210
Powermatic of Canada (Direct Air)

This list is without swiming over the ocean to Europe for the Passive House Certified units which are also excellent but more costly. For example the parts for the industry leader Zender are more than the installed cost for any of the above, including ducts & labor. Despite that there are several Passive House projects in Brooklyn where Zender units have been specified. Germany being the source of Passive House technology is still very much the source of our knowledge and materials.

CEPHEUS – Living Comfort Without Heating

The book CEPHEUS – Living Comfort Without Heating is actually the compilation of Passive House (PH) results for buildings in Central Europe. They turned their findings into a book to give a great overview of different houses with the one common element of being Passive House.

As a Brooklyn Passive House contractor I found it very interesting seeing a diverse array of buildings that all met the PH standard. It was encouraging as we continue our exploration of building PH house brownstones while incorporating our Zero Brownstone goals.

The key to understanding PH is that it is based on populist goals of making good buildings for middle class people. It is not a luxury to live in a comfortable house that costs next to nothing to run. Because of this PH does not cost more to build but produces aesthetically beautiful homes. At the same time PH homes are very affordable to run since they need little to no heating and cooling.

Of course this benefits the global ecology too since PH homes consume much less energy and fossil fuels than “normal” homes.

The CEPHEUS project is a success story. For the most part they succeeded in their goals. This was not a theoretical exercise. The end result was a large body of houses that offer massive improvements over older building techniques.

My one critique is that all the houses are new construction, which consume vast amounts of new materials no matter how green they are. Not only that but they take up more space that previously was nature’s ground.

The book is divided into German on one page and English on another. It has nice photos of the houses, their technical characteristics, the goal of the builder, the cost to build and the final result.

Of course that is the great thing of PH: it is nothing if it does not pass the final test. Unlike useless LEED for example that can have all sorts of bells and whistles, PH gets nothing if it does not pass the very rigorous testing once the building is built. With LEED once it is built, who cares!? Accountability in LEED is a joke. In PH it is everything.

This guarantees results. And the cool thing is that the results are achievable with a normal budget and simple intelligent building. It is really quite amazing. That is why Eco Brooklyn is so into being a Passive House contractor in Brooklyn. We can offer this great service at the same cost to build a “normal” crap brownstone.

From the CEPHEUS site:

Why Build Passive House?

The Passive House standard offers a cost-efficient way of minimizing the energy demand of new buildings in accordance with the global principle of sustainability, while at the same time improving the comfort experienced by building occupants. It thus creates the basis on which it is possible to meet the remaining energy demand of new buildings completely from renewable sources – while keeping within the bounds set by the limited availability of renewables and the affordability of extra costs. The Passive House philosophy builds upon two basic principles:

Principle 1:
Optimize what is essential anyway
What makes the approach so cost-efficient is that, following the principle of simplicity, it relies on optimizing those components of a building which are necessary in any case: The building envelope, the windows and the automatic ventilation system expedient anyway for hygienic reasons. Improving the efficiency of these components to the point at which a separate heat delivery system can be dispensed with yields the savings which largely finance the extra costs of improvement.

Principle 2:
Minimize losses before maximizing gains
Passive Houses prevent available heat from escaping as rigorously as possible (i.e. give precedence to loss minimization). Both the computations carried out with theoretical models and the practical experience gathered with numerous projects show that, under Central European and comparable climatic conditions, such a strategy is fundamentally more efficient than strategies relying primarily upon passive or active solar energy use.