Superinsulated cutaway

There's a broader movement among designers and builders to make very efficient buildings, which represent about half of greenhouse gas emissions in the U.S.

One of the core ideas for new constructions and retrofits is weatherization--sealing air leaks and using lots of insulation. Here is a mock-up of how one builder expects to make existing homes more energy efficient. The foam boards are placed on the exterior of the home, covering walls insulated with cellulose.