I've long been impressed by the simplicity of many of the homemade solar water heaters developed by MOTHER EARTH NEWS' researchers. And now I want to tell their energy-conscious readers about a solar "breadbox" device that I've come up with.
My unit's absorber/storage tank was salvaged from a discarded water heater. I welded legs onto the cylinder and installed an inlet fitting to send the cold water to the bottom of the tank. Then I painted my creation with "hi-temp" flat black paint.
The tank sits in a plywood box, the inside of which is generously insulated with fiberglass. Acrylic plastic (with a couple of galvanized wires for support) is used for the window, and all interior box surfaces facing the water tank are lined with polished sheet aluminum.
My creation's only moving part is an insulated door/reflector that I open every morning and close at night (it's angled just right for catching the low-slung winter sun, making the box even more efficient in January than it is in July).
The exterior surfaces are covered with durable sheet aluminum. The pipe that carries the solar-heated water — as well as any cold water pipes exposed to the outdoors — is also well insulated.
Since installing this simple solar device (which supplies preheated water to our conventional hot water tank), we've had more hot water and a lower power bill. The out-of-pocket costs for my entire project totaled $65. I've been so pleased with the heater that I'm building another one: a modified version of the original unit, which promises to snag even more free BTU than does my first design!