Yes, that could be done, although you have to look at the barriers to that when you do it. We had old programs in houses, under which people put more insulation in their attics. People have put more insulation when they could, and replaced appliances with new appliances. However, the next step is quite expensive--when you try to tackle retrofitting housing, particularly with bad walls, with windows. It's a difficult issue.
There is quite a potential. It's achievable, but you have to look at the barriers.