A solar water heater is the best solar energy investment a homeowner can make. With the new 30% federal tax incentive, state and local incentives, and an 50-80% reduction in your home heating bill, a solar water heater can pay for itself in approx. 3-5 years. From that point, the solar water heater will be heating your water free for the next 25 years.
Solar water heaters come in two different styles, active and passive. An active solar water heater uses pumps to move heated water from the solar collectors to storage tanks. Passive solar water heating systems don't use pumps and have no moving parts but are generally less efficient.
An essential component of solar water heaters is the storage tank. 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.
Three types of solar water heater collectors are used for residential applications:
Solar water heaters generally require backup systems for overcast days and increased usage. for cloudy days and times of increased demand. A variety of backups can be used including tankless water heaters and thermosyphon systems.