The Basics of a Solar Water Heater

Solar hot water heaters (also known as Solar Thermal Collectors or SWHs) directly heat your home’s water using sunlight. They differ from photovoltaic solar panels, which convert sunlight into electricity, in that they heat the water and not the building.

There are a wide variety of SWH systems in use around the world. They range in size, price and efficiency but all consist of the same basic components: a solar thermal collector, a storage tank and interconnecting pipes.

The solar energy collector is the most important part of your system. It is a panel that sits on your roof, and it looks a lot like a solar PV panel. Like solar PV panels, it’s designed to absorb the sun’s energy. Unlike solar PV panels, though, it doesn’t transform that energy into electricity. It transfers the energy to your home’s water by heating a transfer fluid that runs through the collector.

A small automatically controlled pump circulates the sun-heated transfer fluid through the solar storage tank and into your house. When the solar hot water is needed, a sensor detects the temperature difference between the stored water and your household water. If the sensor detects a difference, a switch activates and your solar hot water system starts working. When no hot water is needed, the solar system is shut off.

Depending on where you live, you may need to install a back-up system in case your solar system fails. This can be an electric or gas water heater and it must be connected to the solar system and the water storage tank. The backup water heater should also have an emergency shut-off valve in the event of a power outage.

Solar hot water systems can be a closed-loop or an open-loop system. A closed-loop system uses a mixture of water and food-grade propylene glycol for the transfer fluid, which never comes into contact with your potable water and is only practical in frost-free climates. An open-loop system, on the other hand, uses your potable water and is only practical in warm climates.

Whether you have a closed or open-loop system, an antifreeze fluid needs to circulate through the system. The installer will need to run the pipes for this through your roof. This will involve creating a space large enough to hold the antifreeze fluid piping and, in some cases, the solar hot water storage tank. This will require cutting a few holes in your roof deck, but it is easy to patch the holes and cover them with shingles as soon as they are cut.

Once all of these pieces are in place, you’re ready to start saving money with your new solar water heater! Your utility company will provide you with rebates based on the size of your system and you can take advantage of Federal and State tax credits.  solar water heater Contact us to learn more about how a solar water heater can benefit you. We look forward to assisting you!