An Introduction to Solar Thermal: Solar Heaters and Solar Water Heaters

Learn more about two of the most efficient renewable energy technologies out there!

Unlike its more popular partner, solar electricity, solar thermal technology doesn’t seem to receive the same type of public media coverage. That means people must still have a lot of questions about one of the smartest investments available in solar energy. If you are considering installing some type of renewable energy on your home or business, but you aren’t sure which technology best suits your location, solar thermal is an excellent place to start!

Solar Thermal Technologies

There are two main solar thermal systems: solar water heating and solar air heating. Solar hot water systems can heat the water used in a home or business, for laundry, bathing, dishes and other domestic applications, as well for commercial or industrial applications. Solar air heating provides a supplemental heating source that reduces the load on the primary heating system by warming the air in a building during daylight hours. Both technologies take advantage of the sun’s heat energy, directly using sunlight’s thermal content (from visible and infrared), rather than the less efficient conversion of sunlight to electricity.

There are several things that make solar air heaters and solar water heaters attractive. First, solar thermal is affordable. And it has excellent performance efficiencies and a relatively short payback time. The cost of solar thermal systems for a typical household, excluding installation, can range from as little as $1,500 to about $6,000 (more for larger households or industrial systems). Their performance efficiencies range from 55% to 85%. That means up to 85% of the sun’s heat reaching a solar thermal collector is converted into usable heat for your home!

For an example of investment payback, consider a solar air heater in New England. In central Massachusetts, where altE is located, we can expect the need for home heating for about 5 months of the year. At the current price of home heating oil, and if we expect only a modest 15% offset in heating costs on a 120-gallon-a-month consumption rate, a solar air heater would pay for itself in less than 6 years. A solar water heating system typically pays for itself within 8-9 years. Both solar air heating and solar water heating systems will give you many years of free heat and hot water using just the energy from the sun.