With all the case studies and testing conducted on energy consumed by buildings these past 3 years, two observations were game-changers: 1) we now have the science to halve the energy loads in buildings cheaply; and 2) we have to marry that with an air test to keep from choking ourselves.
So the net result is, the Department of Energy, EPA and even Missouri's Department of Natural Resources (MoDNR) support "BPI" (building performance institute) energy audits to guide the retrofit process. Here's the gig: An auditor does wind tunnel-like testing, combined with infra-red inspections to determine where air leaks happen and where thermal barriers are weak. The fix is simple and cheap. So simple and effective, they also have to test the air and combustion sources to make sure your building has adaquate fresh "make-up" air. Without this step, you breath less oxygen and more carbon dioxide, monoxide, moldy moisture, and cookware gas-off.
The downside is, energy and air testing is required. the upside is, you may end up with fewer episodes with colds and flu, fewer headaches, and better sleep from the fresh make-up air. You get lower utilities and cleaner air. The average return on investment with energy audit driven improvements is 25%!
MoDNR rolled out an energy audit program in 2012, and retrofitted almost 1000 homes. The lessons learned were powerful. With incentives, people come in droves to improve their energy loads. The most effective efficiencies are also the least expensive. Contractors must include BPI audits to identify the efficiencies, and assure the air quality. Hope this helps! See mygreentoolkit .com or DSIREusa .org for access to auditors and incentives.