
I don't know yet what the "payback time" is for the system. I can only estimate how much of our electricity usage has been for hot water. I'm guessing the payback time will be about 10 or 12 years.
I have heard people say that they need a shorter payback time to make it worthwhile. Maybe so, if all you think about is money. But I am saving all that electricity. The nay-sayers then say what's the point, since our electricity here is 90% hydro. But I'm saving the 10% that is fossil-fuel-generated directly. Indirectly, the remaining 90% that comes from hydro is now available for someone else to use, replacing their fossil fuel power. So, whatever sunlight I collect is fossil fuel that someone somewhere doesn't have to burn.
It feels right.