Here is a great case study showing how a couple used green financing to increase the green of their home. Their mortgage did go up but their monthly energy savings were greater. So they end up saving money.

First-time home buyers purchased their home in New York. It was built in 1950, and sold for $260,000. They got an FHA loan for 90% of the value of the property. The lender arranged for them to improve on their investment and recommended an energy-efficient mortgage.

A HERS Rating on the home recommended $3,500 in energy improvements including a new energy star boiler and furnace duct insulation, plus a better thermostat. The lender set aside an extra $3,500 for the improvements, bringing the total loan amount from $234,000 to $237,500. The loan closed, the home buyers moved in, and the improvements were installed. The monthly mortgage payment increased by $22, but they are saving $67 each month through lower utility bills.