A Homemade Solar Water Heater

Enlarge Image Image Gallery WILLIAM J. WEBER

Last summer my family and I started digging out the foundation for our new home. However, after only two sweaty days of laboring under the Florida sun, I realized that we might be going about the whole project in the wrong order. Maybe, I thought, we should be erecting the solar water heater and shower — which we'd already planned as part of our new homestead — before actually constructing the house itself! Well, the more I considered this notion, and the more layers of grime that built up on my tribe's bodies, the more that bit of backward logic began to make a frontward kind of sense.

As you can probably imagine, when I finally proposed my topsy-turvy suggestion to the rest of the family, the whole gang clapped and cheered their approval. So I sat down to research the current literature on solar water heaters. I studied every book and article I could find, but ended up more confused than educated! All the plans called for elaborate pumps, sensors, control switches and other complicated paraphernalia.

(Oh, I did get one fact straight right away: I discovered that we sure weren't going to buy our water heater. Some of those commercial solar units cost over $2,000!)

It took a lot of time and sifting, but I was finally able to devise a simple and inexpensive water warmer that I knew "us regular folks" would be able to build. In fact, my design involves only three steps:

First, build a glass-covered wood "hot box" to catch the sun's heat.

Second, install a manifold of copper water pipes inside this collector box so the gathered warmth will heat water.

Third, hook the outlets from the manifold to a storage tank (this container should be set above the heat collector) so the thermosiphon principle will move water from the collector to the tank. (That fancy-sounding phrase, "thermosiphon principle," simply means that, since hot water rises and cold water sinks, liquid heated in the closed loop system will move up toward our elevated storage container, while cooler water will circulate downhill toward the collector to soak up more sun.)

Glass, Wood and Copper

We initially planned to construct a 48-by-96-inch collector box, but quickly scuttled those dimensions when I learned that a sheet of glass large enough to cover such a container would cost over $60! That price tag forced me to do some rethinking and to come up with an economical solution: I decided to make panels out of old aluminum awning-type windows! Several of the discarded 15-by-34-inch glass rectangles were lying around our homesite, and I was able to scrounge up a few secondhand panes for $1.50 each. Then all we had to do was adjust our collector size (we made it 34-by-90-inch) and line up six windows in a row to get $60 worth of glass cover for less than $9.00. (Besides, the lightweight aluminum units are a cinch to install and would be easy to replace from standard sources of supply if broken.)