Dow Chemical has been testing prototypes of solar roofing shingles called Powerhouse, and intends to start selling Powerhouse in 2011. Powerhouse looks like a regular roofing shingle with a small solar panel where the asphalt would normally be. An X marks the spot where the roofer is supposed to nail so that he won't hit the solar cells. The solar cells are connected together with built-in wiring, and they will convert 13% of the sun's energy into electricity. Two hundred and fifty solar roofing shingles will cover 1, 000 square feet of roof and generate 3.5 kilowatts of electricity on a sunny day. Assuming generous federal and state subsidies, the cost of solar roofing shingles is expected to be about twice as much as you would normally pay for asphalt shingles, about $10, 000 for 1, 000 square feet, but will come with a 25 year guarantee. Solar roofing shingles can be used in conjunction with standard asphalt shingles, and they can be installed by the same roofing contractor with no need for an electrician, which will help to keep the installation costs down.
I use about 300 kilowatts of electricity each month at an annual cost of about $500. Solar roofing shingles on my house could cut my own electric bill by as much as 33% if every day in Erie was sunny. Realistically, the roofs in northern PA are covered in snow for four months of the year and it's frequently cloudy around here, so my actual return would probably be more like a 15% savings on my annual electric bill, or $75 per year. I'm excited by the idea of solar roofing shingles, but I don't think they'll pay for themselves in my particular case. Maybe when this new technology has had another ten years to mature, when I'll be in the market for a new roof for my house, the cost of solar roofing shingles will have lowered enough to be worth the investment.