Water heating<a href="http://kkgzucbfhbv.com"> plenas</a> are heavy (sometimes). Solar electric<a href="http://kkgzucbfhbv.com"> plenas</a> are light about 3 pounds per square foot, which is not any heavier than the other roofing materials that already go on the roof.The big contributors to electric usage are electric heat, air conditioning, and a pool. If you have one or more of these, that will change the answer dramatically. The best thing to do is call up a solar installer, and ask for a free quote. Have a year's worth of electric bills on hand. They'll figure out how large an array would be needed to cut your bill in half, and how much the system would cost. You can always say no thanks after getting the quote.A 3 kW array keeps up with our house in California, but we have no A/C, no electric heat, and no pool.