Join the growing group of people who save between 10 percent to 15 percent annually on their electricity bill with the installation of a solar hot water heater in your home. Solar water heaters utilize solar power to keep a continuous flow of hotter water running in your house that shaves the cost of electricity bills and lowers your environmental impact.
Generally, there are two types of solar water heaters available for residential use. Active solar water heaters and passive solar water heaters. The one you want depends on where you live and how much hot water your household needs.
In the direct system, an electronic control system  compares the temperature of a sensor  located at the solar collector  with the temperature of a sensor  located in the bottom of the hot water storage tank  (where the coldest water is located). When the solar collector temperature is warmer than the water in the bottom of the tank by some predetermined difference (four degrees, for example), the electronic control turns on a small pump , that draws cold water from the bottom of the hot water storage tank and circulates it through the solar collector. Solar heated water is returned to the top of the tank. The circulating pump is very small and typically uses about the same amount of electricity as a 100-watt lightbulb. Another version of this system uses a small photovoltaic (solar electric) panel to operate a direct current (DC) circulating pump.
Advantages. The direct system typically produces the highest operating efficiency because there is no nighttime heat loss from hot water stored on the roof; nor is any efficiency lost through a heat exchange process. Potable water from the hot water storage tank is circulated directly through the collector.
Disadvantages. The only disadvantage of this system is that freeze protection is provided by circulating warm tank water through the collector. This is not a desirable method of freeze protection in climates that experience more than a day or two of freezing weather each year, because energy loss during freezing weather could be significant. Even more important, freezing weather can coincide with a power outage, preventing the pump from circulating warm water through the solar collector.
Integral collector storage systems, also called “batch” solar heaters, combine the hot water storage tank and the solar collector surface into a single component, eliminating the need for circulating pumps or automatic control systems. In its most simple implementation, a water storage tank painted black and sitting out in the sunlight is a rudimentary ICS system.
This type of system works best as a preheater for a conventional or tankless water heater. The cold water line that feeds the conventional water heater is diverted  and sent first through the ICS solar module . Circulation is provided by utility mains pressure. In other words, when hot water is drawn out for use from the conventional water heater , the storage tank is replenished with solar heated water instead of cold water. This allows the electric or gas heater to work substantially less.
Advantages. The biggest advantage is simplicity: the system has no pumps, no temperature sensors, no electronic controls and no heat exchanger. When combined with a tankless water heater, the system can free up five to six square feet of floor space by eliminating the conventional water heater storage tank.
Disadvantages. The biggest disadvantage is nighttime heat loss. Stored heat is lost through the glass cover plate at night, which of necessity cannot be insulated to prevent heat loss. However, this heat loss is reduced in advanced ICS systems by stretching a thin clear film just underneath the glass cover plate, which creates an insulating air gap. Also, while the greater thermal mass of stored hot water within an ICS solar module makes this type of system more freeze resistant than the direct system (above), ICS systems are not appropriate for climates that experience more than four to five freezing nights per year.
Solar water heaters can cut your water heating costs by as much as 50 percent. You only pay for the water heater and installation, the sun takes care of the rest for free.
Solar water heaters are environmentally friendly. Right now, many water heaters either use electricity, natural gas, or a combination of the two. Installing a solar water heater in your house means you can cut your environmental impact by half.
Nationwide energy rates continue to rise while the price of solar panels are at an all-time low. The sooner you install a solar water heater, the sooner you can reduce your monthly energy bills.
The savings are enormous! Federal tax savings allowed owners to reduce the cost of solar water heaters by 30 percent. The only requirement is that your solar water heater generates at least 50 percent of its energy from the sun.
Solar water heaters are an investment. The benefits they provide increase the value of your home.
Solar water heaters have a life expectancy of 20 years with only minor repairs needed after ten years.