What Is the Average Cost to Heat a Pool?

Where you live will affect your energy bills dramatically when it comes to heating an outdoor pool. Of course the rates are higher per kilowatt-hour in some places than others, but more importantly, you should take into consideration the season during which the pool is used and will need to be heated. In Miami an outdoor pool can be used year round, resulting in higher usage, while in Seattle the swimming season is basically limited to the three summer months of June, July and August. How hard the heater must work to maintain a certain water temperature is even a larger factor than the length of season, and this is directly related to geography as well. If the air temperature is warmer than the water temperature, the pump basically has to do nothing. If the air outside is cooler, the pump has to work harder. Assume a 1,000-square-foot uncovered pool with an identical heat pump was installed in each city for the duration of the swimming season. In Miami it would cost approximately $1,460 to keep the water at 80 degrees for the entire year. In Seattle, the annual cost to keep the water at 80 degrees will run $900 despite the short season, according to the U.S. Department of Energy.

Selecting a comfortable water temperature is subjective, but just a few degrees can mean a significant difference in energy usage. In Atlanta, for example, the annual cost of heating the same size uncovered pool to a temperature of 78 degrees is $840. Increasing the temperature to 80 degrees jumps to cost to $1,110, while heating the water to 82 degrees raises the cost to $1,425 per year.

Placing a pool cover on a heated swimming pool may be the best solution for cutting down on heating costs, according to the U.S. Department of Energy. Depending on physical location and length of season, the percentage of savings will vary but will always be dramatic. Assuming the same 1,000-square-foot pool is left uncovered for use 8 hours per day and covered the remaining time, saving can be as high as 90% or more. In Phoenix, an uncovered pool heating cost of $680 per year can be reduced to as little as $45 per year. Even with the heat as high as 82 degrees in a long season like Miami a pool cover can reduce an $1,845 annual cost to $410.

According to SwimmingPool.info, factors that can help you save money on pool heating aside from buying a cover include placing a thermometer in the pool to determine the lowest comfortable temperature to set the thermostat, building a fence or other structure to protect the pool from wind cooling and get a pool heater tune-up each year to be sure it is as efficient as it can be.