What is Solar Domestic Hot Water?

When most people think of solar energy, they think of using it to generate electricity. But for the average home, using the sun's energy for daily hot-water needs can be a more practical and affordable use of the sun's energy. Hot water is the most efficient way to use solar, with the exception of passive solar where you are using sunlight to warm up tile or stone. Solar domestic hot water systems vary, but they generally consist of a well-insulated water tank inside the home and several solar collectors mounted on the roof. A non-toxic, antifreeze fluid is pumped through the collectors on the roof and is warmed by the sun. It then circulates through the water tank transferring the heat to the water in the tank.

Is it More Efficient to Make Electricity or Hot Water with the Sun?

Although it may not be as sexy to heat water as it is to make electricity with the sun's energy, solar domestic hot water systems are much more efficient in using the sun's energy. Water-heating is the third-largest energy expense in most households, after space heating and air conditioning, according to the U.S. Department of Energy.

Hawaii, now requires solar water heaters in new homes. New York and Colorado lead the nation in the installation of solar domestic hot water systems.

What Happens When There Are Periods of Extended Clouds or at Night?

Most systems have a fossil-fuel back-up, such as natural gas or propane, but typically 70-80% of the heating of the water is done by the sun. During the winter months the sun heats the water to nearly 100 degrees. During the summer, these temperatures can reach 140 degrees.

What Do Solar Domestic Hot Water System Cost?

After tax incentives, these systems typically run $6,000 - $8,000. There is currently a federal renewable energy tax credit of 30% of the systems cost, with no cap. Water heaters for swimming pools or hot tubs don't qualify.

How Much Will Installing Such a System Save Us?

It varies from home to home, but in general you can expect a drop of up to 25% in your heating-fuel bill.

About the Author: Dale Schulz is the President of Schulz Homes, www.schulzhomes.com. He has been building and renovating custom homes in the area for nearly a quarter century. He is also the President and Founder of Virginia Renewable Energy, which retrofits new and existing homes with renewable energy systems, such as solar PV panel and wind turbines. You contact him as well as send your questions for future columns to dale@schulzhomes.com. His phone number is 540.687.3367. Schulz Homes office is located on North Hamilton St.