Pooling Your Resources

Give Your Swimming Pool–and Your Utility Bills–an Energy-Smart Makeover

Six million American homes have swimming pools, which provide a cool alternative to the blazing heat of summer months and a refreshing excuse to put off that lawn work just a little bit longer. Unfortunately, the effort it takes to blow up those rafts isn't the only major energy expenditure pools create.
Billions of dollars a year are poured into the maintenance of home pools, and in the process a lot of money, and energy, gets wasted. “If it's just a hole in the ground with water, a pool is pretty low energy intensity,” remarks Michael Lamb, a certified energy manager with the U.S. Department of Energy's Energy Efficiency and Renewable Energy Clearinghouse. “But most people have filters and pumps and heaters that all add up to make it a big energy user.”

An Energy Diet

If you want to put your pool on an energy diet, there are several key slimming strategies. The U.S. Department of Energy's Reduce Swimming Pool Energy Costs! (RSPEC!) program found that water evaporation is the single largest source of energy over-consumption, accounting for 70 percent of the total energy lost in both indoor and outdoor pools. Since you're ultimately paying to reheat each pound of water lost to evaporation, it's much more efficient to simply keep it there in the first place.

A solar pool cover not only heats the water, it helps keep it in place. Using a properly fitting vinyl or plastic “bubble” cover can save hundreds of gallons of water a month (or put another way, it can halve your pool's heating bill). Designing windbreaks around your pool, like hedges or a fence, can also help significantly. A wind blowing over the pool's surface at only seven miles per hour can increase energy consumption by as much as 300 percent.

Switching your pool's heating system to solar is one option that will probably pay out in both cash and clean air in the long run. “Once you install a solar system, it's essentially free heat,” says Kirk Maust of Solar Direct. Solar systems pump the water, with your existing pump, into the tubing of solar collector panels on your rooftop or lawn and then back into the pool, making use of the free, natural warming energy of the sun. Although both electric heat pumps and gas heaters can more easily maintain any temperature, any time, they use fossil fuels to power them, and are for that reason more financially and environmentally costly to operate.

Your filter, too, is a big energy guzzler. As a general rule, it need only run long enough to turn over the water once a day (three to six hours should do it). It's also important to make sure the filter pump and heater you do have are the right size for the job—most are oversized, which reduces effectiveness, causes undue wear and tear and increases your electricity bill. And be sure to shop around for filters that are high-efficiency. Like any electric motor, says Lamb, there are different grades. Look for efficiency information on the equipment's data plate.

Then there are some common-sense approaches you should already be practicing. “Almost every pool I've ever seen is running all the time,” says Lamb. “It's very wasteful.” Put skimmers and pumps on timers. Turn down the pool heater when not in use, and maintain only a comfortable 78 to 80 degrees when swimming. (Raising the temperature even another degree can cost an additional 10 percent.) For lighting around the pool area, use compact fluorescent bulbs, which use half the electricity and last 10 times as long, or solar electric lighting. Backwash your filter only as often as necessary, and be kind to your pump and heater—practicing preventive maintenance maximizes efficiency.

Homeowners can calculate what they'd save giving their pools an energy-smart makeover by downloading a free software program from the U.S. Department of Energy at www.eren.doe.gov/rspec. The program estimates, for instance, that the cost of heating an outdoor pool in Philadelphia throughout the summer is $951, but by using a pool cover, owners may save $627 a year, and a solar heating system, $582.

With savings like that, why suffer through one more year of high bills and air-polluting practices? The next time you're floating around your pool, piña colada in hand, you should be able to rest assured that putting off that lawn mowing isn't the only way you're cutting down on energy.

JENNIFER BOGO is associate editor of E.