apvbguy wrote:i'd be interested in hearing the quotes that you get for a system, the last time I had a salesman here he po-poed the idea of a whole house system and tried to sell me a system to only heat hot water
Frankly, water heating systems are cash cows for installers because of the recurring stream they will make from the service calls.
Here's how I see it (all numbers before tax incentives):
Solar water heating system:
$5000 if you install it yourself (you get a 1-year warranty)
$10,000 if someone else installs it (you then get a 10-year warranty)
You will likely need to repair the system every couple of years, if not more often.
Solar electric system for heating water:
Install a heat-pump water heater (which consumes about 2 MWh/year) and 6 250W PV panels with microinverters.
$4000 if you install it yourself (25-year warranty for panels and microinverters, 10-year warranty on water heater)
$8000 if someone else installs it (same warranty as I'd you install it)
BTW, if your water heater is in your garage, it will help keep it cool and dry in there.
The bottom line, IMO, is that grid-tied electricity is cheaper AND more fungible than hot water, so I tend to prefer that over a solar thermal system.