When I wrote my post What's The Greenest Insulation? It's Getting Harder To Decide Every Day, a number of commenters wondered why I didn't include straw bale. The main reason was that it is usually considered for new builds, but the real problem facing much of North America and the U.K. is insulating what we have rather than building new; we don't need a lot of new houses right now. Straw has a low R-value, so for it to do a good job, it has to be too thick for a retrofit inside a home.
Remodeling
Source: TreeHugger
