High Efficiency Gas Swimming Pool Heaters

Summary: This fact sheet provides an overview of energy-efficient gas swimming pool heaters, as well as some tips for reducing pool heating costs.

Swimming pools are big energy consumers. Pool owner/ operators spend billions of dollars annually to heat the nation's pools. Much of this energy is often wasted and can be saved with proper management. Wasting energy also contributes to our growing air quality problem.

Pool Heating Basics

Why do pools cost so much to heat? Pools lose energy in a variety of ways, but evaporation is by far the largest source of energy loss for swimming pools. When compared to evaporation, all other losses are small.

The reason evaporation has such an impact is that evaporating water requires tremendous amounts of energy. For every gallon of water that evaporates out of a pool, it takes with it over 8500 Btus, and a typical pool loses 1 to 1½ inches of water a week. For a 1000 square foot pool, an inch of water equals 625 gallons or over 50 therms of natural gas every week. (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 the heat loss from a pool.)

Minimize the Heat Loss

The first step in selecting a pool heating system is to minimize the heat loss from the pool, which in the case of pools is primarily evaporation.

What Temperature?

The decision on how warm to keep the pool is up to the individual owner. The temperature recommended by the American Red Cross for competitive swimming is 78° F. This comfort level also coincides with good fuel savings.

However, this may be too cool for young children and the elderly who may require a temperature of 80° F or higher. The typical range for pools is 78°- 82° F. Keep in mind, however, that the energy consumption for each degree rise in temperature will cost from 10-30% more in energy costs depending on your location.

Pool Heater Efficiency Information provided by the US Department of Energy