Solar water heaters can be money savers and are environmentally friendly, but the initial purchase can be expensive. When purchasing this type of heater, it is important to look at the different types of solar water heaters available to determine which type would work best in a specific home. This type of heater can save a household anywhere from 50 to 80 percent of the current fuel cost of water heating, so choosing the very best option will help maximize that savings.
The first thing to look at is geographic location. Though solar systems are available for all climates, different regions will benefit from different types of heaters. A solar water heater is either active or passive. An active water heater uses circulation pumps and controls and a passive heater doesn't. That means an active water heater requires electricity and a passive system does not. Passive solar water heaters are best used only in warm climates.
Active solar water heaters are either indirect or direct circulation systems. Direct circulation systems work in climates that rarely freeze, but colder climates will require an indirect circulation system. Both types use collectors to take the energy from the sun to heat the water. An indirect circulation systems uses a non-freezing heat transfer fluid that circulates through the collectors. This fluid collects heat then transfers it to the water used in the home. Direct systems circulate the water to be used through collectors.
Two types of passive solar hot water heating systems are available. The first is an integral collector-storage system in which the storage tank acts as the collector. These are generally painted black. The sun heats the water directly, then water pressure from a well or city water pushes the heated water to the faucets or another holding tank within the house. The second is a thermosyphon system in which the storage tank is mounted above the collector and gravity pushes the heated water through the tank, but these must be mounted on a roof and are therefore not appropriate for all homes.
So, when selecting a solar water heater, it should first be determined which type is appropriate for the climate in which it will be installed. Next, determine the amount of solar energy available. This will help determine the solar efficiency. The amount of hot water needed must also be noted. This determines the size and type of collector and storage tank. Finally, check prices and weigh all the other factors to determine the biggest savings and most efficient solar water heater for the location, size, and use of the home.