Yes when I wrote rebate, I meant tax credit. With a single layer of 10 year old composite shingles, i figure my options are 1)Remove the current shingles and put new ones on 2)Shingle over the current ones (which will also add additional weight to roof) 3)Put the solar panels up now and hope the previous owners bought really good shingles, if not may have to re-roof in next 10 years which would mean removing solar panels temporarily to do that.