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Solar Thermal - Solar Hot Water Heating

As the pain of increased energy costs rise, so does the installation of Solar Hot Water Heating Systems across the U.S. and Canada. Satisfaction surveys indicate that 94 percent of customers that invest in solar believe they made a good investment. With close to 2 million homes and businesses already using solar heating systems this trend shows no sign of slowing down. Monthly savings on utility bills and increased home values make a solar energy system one of the most cost-effective home improvements available.

Solar Hot Water Can Add Tremendous Savings to Utility Bills

Solar Thermal, more commonly known as Solar Hot Water is the most common type of solar energy used today. Today for domestic residential use solar hot water systems are becoming very popular.

Hot water needed for showering, laundry, dishwashing, cooking and other household needs amounts to between 15 and 30 percent of the average family's energy requirements.

Installing a solar hot water heating system can reduce or eliminate much of that cost and pay for itself in a relatively short time compared to the life of a solar thermal system.



Ground Mounted Solar Thermal Collector Panels Can Be Used When Roof Configuration is Prohibitive for Mounting.

Photo By NASS Member / Friends of the Sun

Depending on the type of solar hot water collectors used most residential applications are between 50 and 100 square feet in size. If the roof is not conducive to the installation, ground mounting or rack mounting can be used to provide the required area of solar thermal panels. Solar thermal panels can also be used for solar space heating but the required area for panels will be much greater.

This type of solar energy doesn't create electricity like solar photovoltaic (solar pv) does. Solar hot water uses the suns warmth to heat up water for direct use or to heat up a glycol mixture inside the solar panel collectors that is then transferred via a pump (active solar thermal design) into the solar tank where the water can be stored for later use or heated more for immediate use.

In many of our market areas, freezing conditions throughout the year demands use of what is called a "closed-loop" system. These Indirect Circulation Systems move a heat-transfer fluid (glycol) through the panels. This type of system includes solar thermal panels (typically mounted on the roof), a pump to circulate the heated glycol solution (similar to antifreeze, but not toxic), a hot water storage tank with a heat exchanger built in and a expansion tank. Insulated piping, controls and plumbing connections are installed connecting the new solar equipment into the homes existing hot water delivery system. The piping that runs through the panels will heat the glycol solution and then the pump will circulate it into the storage tank where the heat is transferred to the water that will be available for use.


Even during the winter or on cloudy days the water available will cut down on any additional energy required as the preheated water is fed into a instant hot water heater to be more fully heated for use.


Many domestic solar hot water systems are used to pre-heat water that is then fed into conventional water heaters. The savings realized by implementing this type of home improvement can reduce energy consumption tremendously and will be well worth the cost of installation in a short time. Even in northern latitudes with harsh winters the solar hot water system will meet around 65% of the annual energy requirement. Considering the high percentage of energy use that goes to producing hot water, that can amount to substantial annual savings immediately.

Using the sun to heat water is an age old technique and has been utilized world wide in many cultures especially in warm, sunny climates. Improvements in technology have allowed solar hot water heating systems to be used anywhere across the U.S and Canada.

In areas that receive a great deal of sunlight like the desert Southwest, Southern California, Texas and Florida solar hot water is used in a direct heating method where the actual water for use is heated and then delivered for use in the home. These systems are called Direct Circulation Systems. Pumps circulate household water through the collectors and into the home. They work well in climates where it rarely freezes.

Heating pools using a solar hot water system is a common application of solar technology to save on traditional energy costs. Solar pool heating can pay for itself in the first few years and extend the length of your pool use season at the same time.

Photo By NASS Member / Renewable Energy of Plum Hollow