Nearly 300 homes in this San Diego development have solar water heating systems, and some have solar electric systems. The solar water heating collectors on the roof look like skylights. One of the most cost-effective ways to include renewable technologies into a building is by incorporating solar hot water.

A typical residential solar water-heating system reduces the need for conventional water heating by about two-thirds. It minimizes the expense of electricity or fossil fuel to heat the water and reduces the associated environmental impacts.

Solar Water Heating for Buildings

Most solar water-heating systems for buildings have two main parts: (1) a solar collector and (2) a storage tank. The most common collector used in solar hot water systems is the flat-plate collector.

Solar water heaters use the sun to heat either water or a heat-transfer fluid in the collector. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. The tank can be a modified standard 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.