"mmccaws" wrote in message roups.com...
I was thinking of mounting solar panels on the south side and roof to
eak out every watt I could then power a water heater and pump of sorts
which would circulate through the floor.

If you mount solar panels on the roof and walls, won't you block light
from the greenhouse? I suspect that allowing the sun to warm the
greenhouse directly and perhaps using some passive solar
collectors(e.g. black barrels of water) inside, will be much more
efficient than trying to convert sunlight to electricity and then
heating water to heat the greenhouse.

If you have your solar panels off to the side, that's another matter.
Then you would get passive gain from the sun shining on the greenhouse
AND electricity from the solar panels.

Nick