Do you use electric shower or maybe natural gas? How much do you spent to have hot water? I'm thinking about to put 10 130W modules on 1 m2 black metal sheet and make the test. It will cost me 1000 euros and if it works i'm going to have maybe 800W/h of electricity and hot water on the end of the day. maybe wont work, as soon as i have the money i'm going to give this a try.