Solar Hot Water Heaters
Return of Investment in the Fast Lane

Did you know that domestic water heaters account for 20-30% of the average domestic energy bill?  The installation of a solar hot water heater will dramatically reduce your energy bill and at the same time supply you with an abundance of hot water. The payback period for a solar domestic water heater is a few years. After which, you will enjoy a free of charge hot water supply thereafter.  Solar water heating does not release pollutants and carbon-dioxide and installing a solar domestic water heater is equivalent to eliminating one family car off the congested roads.

What Is A Solar Water Heating System?

The two essential parts of any solar hot water heater are the solar collector and the solar water tank. The solar collector is the water heater; it is a small flat greenhouse with water pipes installed inside. Cold water enters the collector on one side and leaves warmer on the other side. The water flows into a water tank and is recycled to the solar collector again and again until the tank’s water temperature reaches the desired temperature.

What Are The Types Of Solar Hot Water Heaters?

The simplest and cheapest type is called a passive solar hot water heater. It has only the collector and the water tank. The tank is installed above the collector and the hot water from the collector goes naturally upward to the tank, (thermo-siphon effect), while colder water from the tank flows back to the collector. In case the tank must be installed higher than the collector, a water pump is added and the system is called an active solar water heating system.

For regions where the water might freeze, glycol flows in the collector to tank and back in a closed loop and an heat exchanger is used to heat up the water in the tank. This system is called an indirect solar water heater.  For really cold and not so sunny regions, a more efficient collector, the evacuated tube solar collector is used.

What Is The Price Of The Solar Water Heating System?

Depending on the solar heater type and the size of the family, domestic solar hot water systems can cost between $1,500 to $3,500. With the available tax credits, the payback time can be as short as three years. With life expectancy of over 10 years, over 7 years of practically free of charge domestic hot water can be expected.  Your next step after installing a very cost effective solar water heater is to install your own solar power generator to reduce your electricity bills.

Why Don’t We See More Solar Domestic Water Heaters?

Unlike the situation in Israel and Spain where over 90% of the families enjoy solar heated water, these systems are sparsely installed in the US. It is estimated that 3% of Israel's energy needs are fulfilled by domestic water heaters; just imagine how the US could reduce CO2 emissions if one out of every 30 coal powered power plants were eliminated.

One reason might be that the American public is still unaware of the benefits of solar water heaters.   The other reason might be the need for costly building permits.

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At the same time as the costs of solar electricity continues to fall, more and more households are turning to residential solar energy to lower their energy use and save on the growing costs of power.

3 Responses to “Solar Hot Water Heaters
Return of Investment in the Fast Lane”


  1. Solar Energy: Thinking Outside the Panel Says:

    […] solar hot water heater system can cut household water heating costs by up to 70%. An open-loop, passive batch system such as a […]


  2. Solar Thermal Applications - Solar Water Heating - Photovoltaic Systems Says:

    […] great deal of money is spent annually in the United States simply heating water. In 2001, the U.S. Energy Information Administration calculated that each household in the nation […]


  3. Solar Energy Tax Credits - Tax Incentives For Solar Power Says:

    […] – solar water heat, […]

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