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We bought the solar hot water system from Home Depot (Universal), the heating unit is part of a 600 gallon tank pressure system.  The hot water is very hot - 145 degrees.   You have to be careful to mix at the faucet to avoid scalding! 

Spot,

I too have thought about a solar water heater, but I suspect I will go with a tankless electric instead.  Primary reason is low usage of hot water will make the cost of the solar prohibitive.  In addition, I've got the same concern that Sitka mentioned, the ability to moderate the temperature.    a link to a decent website on the subject, but the following comment from the author sums up my concerns:

"With most systems, there’s no way to lower the temperature of water going from the solar storage tank to the standard water heater. If you lower the setpoint of your conventional water heater, it may lower your bill slightly, but with such a minimal water heating load, I’m not surprised that you saw only a minimal difference in your water heating bill. These systems make the most difference when they are used in a high demand situation where your demand matches your peak sun hours. If someone promised you big savings, I’m sorry to say they misled you. Payback time in many circumstances, even with tax credits, is often a decade or two. Some systems never pay back the amount invested if hot water use and utility costs are low."

Great input. Thanks guys!

Well, I should explain...before we installed the cistern tank, the water from the street was warm enough to shower without any heater, it was just heated by the warm ground.  But after installing the storage tank and pressure tank, the water temp was much cooler and I added the solar water heater for our comfort.   It was a good investment for us to have unlimited hot water for two units for the bathrooms, kitchens and washers.

Thanks Sitka.  For me, the decision not to go with solar is based on two factors, both of which were mentioned in my previous post.  In the first place, I'm an empty nester, so it's just me and the missus.  Not a lot of demand for hot water.  As such, it would take many years for the system to pay for itself.  Second, I'm concerned about the possibility of scalding.  Only in the most expensive systems is it possible to thermostatically control the temperature of the hot water coming from the solar water heater.  And as I grow older, the risk of scalding grows greater.

Considering our low demand and the relatively warm temperature of the "cold" water, an on-demand, tankless system makes more sense.  Of course, different folks with different needs may find the solar system makes more sense for them.