Solar Energy

for domestic hot water?

In the northern hemisphere the simplest solar energy system is to face the windows south. Hang insulating curtains. Open or close these curtains when appropriate.

If you have access to black plastic pipe you can lay it on the ground or put it on your south-facing roof. 3/4 inch holds 0.0206 gallons per foot, 1 inch holds .0346, so 100 ft will provide about 2-3.5 gallons of hot water after about an hour in bright sun, assuming you are in a hot part of the world. No pump required if you have a holding tank on your roof.