Swimming Pool Energy Efficiency

Looking for a way to lower your pool's operating costs? One way might be to review the recommendations of the U. S. Department of Energy, which has extensively studied various energy conservation methods for heating swimming pools and the resulting costs savings. Their findings hit the bottom line - it is possible to reduce energy costs by as much as 50 - 70%!

The Department of Energy has found that water evaporation is overwhelming the single largest source of energy over consumption, accounting for 70% of total energy lost in both outdoor and indoor pools. With evaporating water goes much of a swimming pool's heat. For every gallon of water that evaporates it takes with it over 8,500 BTUs, and a typical pool loses 1 to 1 1/2 inches of water a week. For a 1,000 square foot pool, an inch equals 625 gallons or over 50 therms of natural gas. A therm is equal to 100,000 BTUs. Because of all the energy required to evaporate a gallon of water, evaporation turns out to be 70% of heat loss from a pool.

Also consider that it takes only 1 BTU to raise a pound of water 1 degree but each pound of 80 degree water that evaporates takes 1,048 BTUs of heat out of the pool. In other words, it's much more efficient to keep as much of the water you've already heated (and paid to heat) in the pool than to keep replacing that heat when lost. And, over consumption of energy is not only costly, it also increases air pollution

Energy Conservation Recommendations for All Pools

• Covering your pool when not in use to prevent heat loss can be the single most important effective thing in reducing heating costs, with savings of 50 - 70% possible. Pool covers can reduce the amount of make-up water required by 30 -50%, reduce chemical consumption by 35 - 60% and cut cleaning time by keeping dirt and debris out of the pool.
  
  Note that outdoor swimming pools absorb 75% to 85% of the solar energy that strikes pool surface, some of which will be lost with the use of a pool cover. However, other environmental conditions, such as humidity, wind, over night air temperatures, and higher pool water temperature, effect the rate of evaporation. These conditions need to be considered when determining whether or not to use a pool cover during daylight hours. (Recreonics carries both solar and thermal swimming pool covers.)
  
  
• High-efficiency pool heaters, electric heat pumps and properly sized pumps and motors can all save utility costs.  In fact, motors can often consume many times their original cost in electricity costs in just the first year of operation! (Recreonics carries high-efficiency pool heaters and filtration systems.)
  
  
• Consider the installation of a solar-powered heating system which have very low operating costs.  Solar energy is abundantly available and environmentally friendly. Solar-powered heating systems can raise pool water temperatures 10°F to 20°F and are most efficient in mild temperature.
  
  
• Maintain efficient daily operations. Turn down the pool heater when the pool is not in use and maintain appropriate water temperatures when in use (78°-80° for active swimming, 82°-84° for recreational use).  Raising the water temperature just 1°F can costs an additional 10 - 30%, depending on your location. Keep a thermometer in the pool to help determine the temperature that is best for your pool and mark the "comfort settings" on the thermostat dial to avoid accidental overheating. Backwash the pool filter only as much as necessary to avoid wasting water and energy and be sure to keep drain systems clear to allow the free flow of water.  Use compact fluorescent or high intensity discharge lamps for lighting needs.
  

Recommendations for Outdoor Pools
In addition, outdoor swimming pool owners and operators should consider the appropriateness of installing windbreaks as even modest winds increase evaporation rates.  A mere 7mph wind on the pool surface can increase energy consumption by 300%!  Windbreaks should be tall enough and close enough to the pool to limit air turbulence over the pool surface.

Recommendations for Indoor Pools
Indoor swimming pools typically have higher energy costs as they are usually open year-round, do not receive heat from the sun and require ventilation systems to reduce humidity levels that cause damage to structural components. For these facilities pool covers are important in conserving pool heat and reducing ventilation requirements.  Heat recovery units installed in the ventilation system can salvage heat from ventilating air, while installing dehumidification systems can reduce the amount of ventilation needed.  Utility costs can also be reduced by turndown building temperatures when the facility is not in use.

For more information please also view the Department of Energy's website regarding energy efficiency and renewable energy.