Some like it hot...

Not that I can afford a solar hot water system, but we'll need a new water heater before too long so I did a little research into what would be appropriate for Illinois. It's possible to buy a hot water tank with a heat exchanger in it for a pressurized glycol loop up to a flat plate collector on the roof. I'd need the tank, a pump, collector controller and some valves, including a temper valve.