Well, I'm not sure how effective it will be, but my husband has actually insulated a good portion of our garage wall with them. He cuts them apart and fits them in between the ...ummmm, I'm sure there's a more appropriate construction word to use here....2X4's. I have a hard time beleiving that they will block out cold in the winter when he gets it finished, but he's an engineer and swears it will work! Hey, they gotta go somewhere, right?