Weber decided to start construction of his house by building a homemade solar water heater… “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.” Thanks Star! Link.
HOW TO – Make a homemade solar water heater