President Obama supports home energy rebates for homeowners to make their homes more energy efficient. The existing home market is much bigger than new homes. So, there's lots of opportunities to be created here. Via White House.
...I'm calling on Congress to consider a new program to provide incentives for consumers who retrofit their homes to become more energy-efficient, which we know creates jobs, saves money for families, and reduces the pollution that threatens our environment. And I'm proposing that we expand select Recovery Act initiatives to promote energy efficiency and clean energy jobs which have been proven to be particularly popular and effective.
The additional values of energy retrofit (besides all the good stuff mentioned above) is the potential for higher homes valuation. Improvements should be documented, sort like comparing the before and after, for potential buyers to see the 'values' in it.