Solar water heaters (also called solar domestic hot water systems) can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use--sunshine is free.
How They Work
Solar water heating systems include storage tanks and solar collectors. There are two main types of solar water heating systems, open loop which routes water through solar collectors on the roof, and closed loop which uses a heat exchange process using glycol as the heat medium to heat water in the water storage tank. Closed loop systems offer better freeze and overheat protection, and can take advantage of the current California solar rebate program for solar thermal hot water.
Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.