Using Sunlight To Heat Your Water

Using Sunlight To Heat Your Water

When Cindy Roché and Bob Korfhage open their electric bill each month, they can't help but smile. While their east Medford neighbors average about $150 a month to power their homes, Cindy and Bob average about $18, not bad for a 2,080-square-foot, all-electric home.

To achieve such low energy bills, the couple incorporated numerous energy-efficient features into the design of their brand-new home, such as compact fluorescent light bulbs, a solar electric system, solar light tubes, energy-efficient appliances, lots of insulation and more.

But perhaps the biggest saver for them is the solar water heater that sits on the roof overlooking their backyard on David Lane.

According to the Energy Trust of Oregon, 25 percent of a home's energy goes to heating water. Solar hot-water systems reduce that cost by using the sun to pre-heat the water before it goes into your water heater.

Roslyn and Donald Parker of Ashland can attest to those estimates. The Parkers installed a solar water-heating system on their house earlier this year, and their electric bills have gone down 25 to 30 percent per month, Roslyn says.

Solar hot-water systems contain heat collectors, storage tanks and, depending on the type of system, electric pumps. The heat collectors gather heat from the sun and pass that heat to fluid-filled tubes, which can contain either water or glycol, a type of antifreeze. Those solar-heated tubes heat your water, and then the hot water goes to an insulated storage tank. From there, it heads to your water heater.

Because the water is pre-heated, it doesn't take much energy — if any — to heat it for household use, says Gary Thomas, owner of Solar Man Company in Grants Pass, who installed the Parkers' solar system.

In the summer months, the water coming off the roof may even be too hot, requiring an influx of fresh water to cool it, says Tim Dawson, owner of Solar Collection, Inc. in Talent, who installed the system used by Bob and Cindy. In the summer, the water may heat to as high as 150 degrees. In the fall and spring, the incoming water temperature will be around 100 to 120 degrees. On a sunny winter day the water may heat to 80 or 90 degrees.

When the year-round temperatures in Southern Oregon are averaged out, 65 percent of your water will have been heated by the sun, rather than by your gas or electric water heater, Dawson says.

Several types of solar water systems are available, including active systems, which use pumps and valves to move fluid, and passive systems, which don't use pumps. The system used by Bob and Cindy is called a drain-back system, which does not require glycol to keep it from freezing in the winter. The Parkers opted for a glycol system.

The type of system that is best for you will depend on a number of factors, including the size of your family and the location of your house. Solar contractors will use a spreadsheet or special computer program to help determine the right size and type of system for your house.

"The biggest thing is access to sunlight," Dawson says. "You need a roof surface within 30 to 35 degrees of south, and a fairly unobstructed exposure until 3:30 in the afternoon."

In most cases you will be able to use your existing water heater, Thomas says, though some older tanks may need to be replaced for best results. "The last three systems I installed, I recommended they replace the water tank," Thomas says.

Dawson says it takes two days to install a solar hot-water system, and the system should last 20 to 30 years.

While the prospect of lower energy bills was a definite incentive, the Parkers say they were motivated most by a desire to help the environment. "We knew it would be a financial savings, but what really stimulated us was a desire to do something good environmentally," Roslyn says. "We got to contribute and, in a sense, we get paid for it. It's a win-win."

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