Honeymonster we are just past the first year of having the panels, total cost was £10,000, we reckon we have had including power used abt. £1000 in the first year. Shortly after fitting we were discussing the fact we had no water heating panel and were discussing getting one but it was pricey as an after fit. We got a letter from the contracter who fitted panes offering a device, which automatically sends any power not being used to the hot water, we reckon it will pay back very quickly, water heat is better to. It cost £456. Worth every penny and that`a a Scotsman talking. I think it ws called an i-booster.