See, for example, this article by Mari Saito in the Philadelphia Business Journal, describing one condo buyer's shock that her monthly electricity bill went from about $280 per month in her former loft to just $76.
And in a related article by Diane M. Fiske, the Journal describes how one local developer is coming up with efficient ways to build homes that are both affordable and energy-saving. An important part of the strategy is the use of SIPS, or "standard insulated panels." These panels are made of wood (either young farmed trees or leftover wood flakes) and a foam insulating material. They're precut to the designer's specifications and put together on site, like a giant puzzle. They're getting high reviews for environmental friendliness (like reduced wood waste) and tight, heat-conserving qualities.
By the way, if you're building your own house, SIPS might be a good option as well. For more information on SIPS, see:
