Another name for solar water heaters is "domestic hot water systems". They are a very cost-efficient way of keeping your home warm. One great perk of this particular process is that it can be used regardless of what type of climate you live in, and you get your energy from a free source, the sun.

There are two types of solar heating systems that are most commonly used for residential purposes. Each of these collectors includes a storage tank and a solar collector. The first type is "active" which has circulating pumps and controls and the second type is "passive" which don’t require pumps or controls.

Solar water heaters need a storage tank that is insulated well. They have an outlet and an inlet that is connected to the collector. A two-tank system has a water heater that is powered by the sun and preheats water before it enters the water heater. In a one-tank system the back-up water heater is joined with the solar storage in one tank.

For residential purposes there are three types of solar collectors; Flat-plate collector, integral collector-storage systems, and evacuated-tube solar collectors. The flat-plate collector has glazed flat-plate collectors. It is insulated and contains weatherproof boxes with a dark absorber plate under one or more polymer (plastic) cover. There are also unglazed flat-plate collectors that are often used for heating pools and also have a dark absorber plate, but without a cover.

The second type is integral collector-storage systems. They are also known by their initials ICS, or batch systems. They have at least one black tank or insulated tubes within a glazed box. The cold water starts by rushing into the solar collector where it is preheated. From here the water flows to the backup water heater and creates a reliable source of hot water. An important note is that these should only be installed in mild-freeze climates because the pipes could freeze when outside in the cold weather.

The last type of solar collector is the evacuated-tube solar collector. In this type of solar collector there are dual rows of parallel transparent glass tubes. In each tube there is an outer glass tube and a metal absorber tube which is attached to the fin. The fin has a coating that absorbs the solar energy and at the same time inhibits radiative heat loss. This type of collector is the most commonly used collector in U.S. commercial applications.

There are also two types of active solar water heating systems. The first type is the Direct Circulation system. This system has pumps that circulate household water through the collectors and back into the home. This type of collector is only effective in a climate that doesn’t freeze often.

The second type of commercial solar heating system is the Indirect Circulation system. This system has pumps that circulate a nom-freezing fluid that transfers heat. The heat flows through the collectors and then through a heat exchanger. After the water is heated in this fashion it flows into the home and heats it. These are very good for homes that are in areas that are prone to freezing.