Feature Article - November 2006
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Special Supplement: Problem-Solver Guidebook

By Stacy St. Clair and Emily Tipping

Minimizing Your Pool's Energy Consumption

Dreading that time of the month when your heating bill arrives? You're not alone. Aquatics managers across the country are grappling with soaring heating costs. Fortunately, the U.S. Department of Energy has studied the issue extensively and has come up with recommendations that could reduce energy costs by as much as 70 percent.

Q: Why are my bills so high?

A: The Department of Energy has found that water evaporation is the largest single source of over-consumption. It accounts for 70 percent of total energy lost in both outdoor and indoor pools. As evaporation goes, so goes much of the swimming pool's heat. For every gallon of water that evaporates, more than 8,500 BTUs are lost, too.

Q: How much water am I losing to evaporation?

A: A typical pool loses 1 to 1.5 inches of water a week. For a 1,000-square-foot pool, an inch equals 625 gallons or more than 50 therms of natural gas. (A therm is equal to 100,000 BTUs.) Given all the energy required to evaporate a gallon of water, this results in the pool losing 70 percent of its heat. Simply put, it's much more efficient to keep as much of the water you've already heated in the pool than to keep replacing lost heat.

Q: How can I prevent heat loss?

A: Covering your pool when it's not in use can be the single most effective thing you can do to reduce heating costs. In fact, industry estimates suggest that pool blankets can reduce heating costs by 50 to 70 percent. Pool covers also can reduce the amount of makeup water required by 30 to 50 percent, slash chemical consumption by as much as 60 percent and cut cleaning time by keeping dirt and debris out of the pool.

Q: Are the covers for nighttime use only?

A: It depends. Outdoor pools absorb 75 to 85 percent of the solar energy that strikes the pool surface. Some of this will be lost with the use of a pool cover. However, other environmental conditions—humidity, wind, overnight air temperatures and higher water temperatures—impact evaporation rates. These conditions need to be considered when determining whether or not to use a pool cover during the daytime.

Q: Are there any mechanical solutions for cutting energy costs?

A: High-efficiency pool heaters, electric heat pumps and properly sized pumps and motors can all save utility costs. In fact, motors often can recoup their costs in the first year with energy savings.

Q: What about alternative energy forms?

A: Solar-powered heating systems offer a legitimate way to lower operating costs. Solar energy is abundantly available and environmentally friendly. Solar-powered heating systems can raise pool water temperatures 10 to 20 degrees Fahrenheit and are most efficient in mild climates.

Q: What should I be doing on a daily basis?

A: It's important to maintain efficient daily operations. Turn down the pool heater when the pool is not in use. When it's in use, maintain proper water temperatures (78 to 80 degrees for active swimming and 82 to 84 degrees for recreational use. Raising the water temperature 1 degree can boost the heating costs by 10 to 30 percent, depending on location. Backwash the pool filter only as much as necessary to avoid wasting water and energy.

Q: Is there anything special that outdoor pools should be doing?

A: Consider installing windbreaks to decrease evaporation rates. A mere 7-mile-per-hour wind on the pool surface can dramatically increase energy consumption. Windbreaks should be tall enough and close enough to the pool to limit the air turbulence over the pool surface.


   Recreonics Inc.: 800-428-3254   

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