The collectors turn the sun's energy into heat, which is transferred to the water in either your building's hot water tank, or a dedicated solar hot water tank, via copper piping loops from the collectors. This loop is filled with a non-toxic propylene glycol mixture, which remains inside the collectors and piping at all times. Whenever the sun shines on the collectors, the circulating pump comes on, and the solar fluid circulates within the closed loop. The fluid gets extremely hot inside the collectors and travels through the piping to a heat exchanger, which transfers the heat from the glycol loop to a water loop. Because solar thermal hot water collectors use the full spectrum of the sun, they efficiently absorb even the diffused solar radiation present on cloudy days. They do not need direct sunlight to operate and are not nearly as impacted by shading issues like solar electric (PV) modules are.

For many businesses and commercial buildings heating water is a huge energy load and major expense. Installing a solar thermal water heating system will save your business significant money, help protect the environment, and show your customers your company's dedication to the environment and community. Experts agree that a commercial solar thermal water heater is far and away the easiest initial investment in renewable energy.