Homeowners will be able to claim and 30% tax credut for purchases of new furnances, windows and insulation through 2010.  Attached is a link regarding the stimulus bill.

http://greeninc.blogs.nytimes.com/2009/02/17/obama-signs-stimulus-packed-with-clean-energy-provisions/?scp=1&sq=energy%20efficient%20tax%20credit&st=cse