Water Power
Hot
Water
Solar Water Heating was first commercially installed in homes in the 1970’s and over time the systems have proved themselves to be reliable, virtually maintenance free and cost effective. Solar Water Heating can be used on homes and commercial buildings. Typically, solar panels will deliver most of your hot water over the summer months and warm water during the winter months - over a year this equates to about 50% to 70% of a household’s hot water.
Most solar water heating systems for buildings have two main parts: a solar collector and a storage tank. The most common collector is called a flat-plate collector. Mounted on the roof, it consists of a thin, flat, rectangular box with a transparent cover that faces the sun. Small tubes run through the box and carry the fluid — either water or other fluid, such as an antifreeze solution — to be heated. The tubes are attached to an absorber plate, which is painted black to absorb the heat. As heat builds up in the collector, it heats the fluid passing through the tubes.
The storage tank then holds the hot liquid. It can be just a modified water heater, but it is usually larger and very well-insulated. Solar water heating systems can be either active or passive, but the most common are active systems. Active systems rely on pumps to move the liquid between the collector and the storage tank, while passive systems rely on gravity and the tendency for water to naturally circulate as it is heated.
How It Works
Incentives are now available for Solar Water-Heating Systems!
Rebates are now available for qualifying solar water heating systems under the California Solar Initiative's Thermal program, CSI-Thermal.
- CSI-Thermal rebates are available to homeowners who install solar water heating systems in the service territories of PG&E, SCE, SoCalGas and SDG&E.
- Solar water heating systems must have a Solar Rating and Certification Corporation (SRCC) OG-300 rating.
- Solar water heating systems may displace either natural gas or electric water heaters.
- Rebates are available for qualifying systems that were installed after July 15, 2009.
