Solar Hot Water
All of our OTechnology designs feature rooftop solar hot water panels at no cost. These panels can provide up to 70% of the hot water your building needs each year. Solar water heaters, sometimes called solar domestic hot water systems, use the sun to heat either water or a heat-transfer fluid in collectors. A typical system will reduce the need for conventional energy source for water heating by about two-thirds, and is the most cost-effective way to use solar energy in your building.
The operation of solar hot water systems use a pollution-free form of renewable energy. By using one of these systems, you will be significantly reducing the carbon dioxide (CO2), nitrogen oxides, sulfur dioxide, and the other air pollution and wastes created when your utility generates power or you burn fuel to heat your household water. When a solar hot water system replaces an electric water heater, the electricity displaced over 20 years represents more than 50 tons of avoided CO2 emissions alone. Carbon dioxide traps heat in the upper atmosphere, thus contributing to global warming.
Solar water heaters use renewable energy and hence reduce our dependence on limited natural resources. The upstream environmental benefits from reduced energy use are numerous: reduced habitat destruction caused by the extraction and transport of fossil and nuclear fuels, reduced air pollution and acid rain, and avoided radioactive waste. Clearly, there are resource impacts involved in extracting and processing the minerals for the copper and glass in a panel. However, this “embodied energy” is generally offset within a few months of active use of the If your domestic hot water heater is currently electric, using a solar hot water system is approximately the equivalent of offsetting the CO2 of a fuel-efficient car.
Health and / or Social Benefits
Solar water heaters have no effect on indoor air quality but do promote healthier air quality outdoors. Water heating accounts for a substantial portion of energy use at many residential, commercial, institutional, and federal facilities. Nationwide, approximately 18% of energy use in residential buildings and 4% in commercial buildings is for water heating. Solar water heating systems, which uses the sun’s energy rather than electricity or gas to heat water, can efficiently provide up to 80% of the hot water needs—without fuel cost or pollution and with minimal operation and maintenance expense. Solar currently represents 1% of the water heating market (about 3% of buildings have solar and it provides about 1/3 of the energy for each). Switching our society to solar hot water helps us lower our dependence upon foreign oil and uses the sun’s free energy.
Research shows that an average household with an electric water heater spends about 25% of its home energy costs on heating water. Solar water heater economics can compare quite favorably with those of electric or gas water heaters depending on the local fuel costs. Heating water with the sun also means long-term benefits, such as being cushioned from future fuel shortages and price increases and reducing your home’s environmental impact.
Paybacks vary widely, but a simple payback of four to eight years on a well-designed and properly installed solar water heater can typically be expected. After the payback period, savings are accrued over the life of the system, which ranges from 15 to 40 years, depending on the system and how well it is maintained. If building a new home or refinancing a present home to do a major renovation, the economics are even more attractive. The cost of including the price of a solar water heater in a new 30-year mortgage is usually between $13 and $20 per month.
Solar Water Heaters Fact Sheet (PDF)
Build It Green
A Solar Water Heater Can Save A Family A Lot of Money
San Francisco / Bay Area Real Estate News Website, February 2011
Solar Water Heating
National Institute of Building Sciences Website, 2012