"RJ" wrote in message
...

We get LOTS of sunshine in Southern Arizona.

Without getting too elaborate, here's my idea;

Loop about 100' of plastic pipe in the rooftop.
Connect FROM cold inlet TO my water heater.

During the daytime, ( which is when we use hot water )
Water would be solar-preheated before going to the water heater.

No need for any "controls" except to disconnect it
in the wintertime. ( temps do dip to freezing at nite in mid-winter )

You could make a simple batch pre-heater out of an old water heater tank.

http://solarcooking.org/bkerr/SWHeaterRev-1d.pdf
http://www.motherearthnews.com/DIY/1...er-Heater.aspx
http://www.cjonline.com/stories/0414...erheater.shtml
http://www.infinitepower.org/pdf/FactSheet-10.pdf

Bob