A solar domestic hot water system pays for itself – and then begins paying you – faster than any other type of renewable energy system.

What is SDHW?

Who hasn’t returned to their locked car on a summer day to find the interior scorching hot? Solar domestic hot water (SDHW) systems use the same “greenhouse effect” to heat water for use in homes and businesses.

An SDHW system works in tandem with your existing water heater. This means you get hot water from the solar system when the sun is shining, and never need to worry about not having hot water when it's not.

How does it work?

Closed-loop SDHW systems trap the sun’s energy inside an array of box-like collectors to heat a freeze-resistant, food-grade propylene glycol liquid in a series of copper tubes. A pump circulates the heated glycol from the collector to the water tank where it passes through a coil and transfers its heat to replenish the hot water supply.

SDHW collectors are weather proof, heavily insulated and designed to absorb the maximum amount of available heat. A tempered solar glass cover allows solar radiation to enter but prevents approximately 95 percent of the heat from escaping. A specially treated copper absorber plate is placed next to the copper tubing to transfer even more of the sun’s radiated energy to the heat transfer fluid. Then the liquid glycol in the copper tubing circulates through a heat exchanger coil inside a well-insulated holding tank, not unlike the tank used in your conventional water heater.

The heated glycol transfers its heat to the water in the tank before returning to the collector where it’s heated again and the cycle repeats.

• Sunlight passes through the glass cover on the solar collector.
• Trapped inside the collector, the sun’s energy heats the food-grade glycol solution, which is isolated from the water supply inside a series of copper tubes.
• A pump circulates the glycol solution through a heat exchanger inside the hot water tank.
• The heated water is distributed throughout the building.

How does it save money?

SDHW uses energy from the sun to offset the cost of the natural gas, propane, heating oil or conventional electricity normally used to heat your water. Over the year a SDHW system can provide as much as 60%-65% of all water heating needs. During the summer months the system operates at its maximum with little extra heating from conventional sources required.

What is the payback time?

About 20 percent of the average family's energy use comes from the cost of operating a domestic water heater. The savings garnered from an SDHW system, and the corresponding increase in home resale value, will usually pay the cost of installation within 6-8 years, the fastest payback of any renewable energy system. And, over the next 40+ years of its life expectancy, your SDHW system is actually putting money back in your pocket!