I am on the fence with this one. I have a 16x32 IG which roughly equates to 512 sqft. I have to minally cover 1/2 of the square feet which will bring me to 256. I can only fit about 240 sqft of Sungrabber on my east facing exposure roof. It gets quite a bit of sun due to the pitch and lack of a lot of trees. I don't want to invest on this one if it really isn't going to make a big difference. What do you all think?