Educational · 6 min read
How Much Does a Pool Heater Cost to Run? (2026 Data)
An electric heat pump pool heater costs about $57 a month to run in summer at the April 2026 US average rate of 18.05 cents per kWh, based on a 5,000-watt unit cycling a few hours a day. Run it harder in the cooler shoulder months and it climbs past $110. The older electric resistance heaters it replaced cost roughly five times as much for the same water temperature. A pool heater is the seasonal load that rarely gets a real number put to it, and the number depends almost entirely on which type sits next to the pump.
What a pool heater costs per month
A 5,000-watt heat pump pool heater draws about 3.5 kWh for every hour it actually runs, because the compressor cycles on and off to hold the set temperature instead of running flat out. That works out to $0.63 an hour at the US average rate from the EIA Electric Power Monthly. On a typical summer schedule of three hours of run time a day, that's 10.5 kWh, or $1.90 a day and about $57 a month.
The shoulder season costs more, not less. In spring and fall the water starts colder and the air is cooler, so the heater runs closer to six hours a day to hold the same temperature: about 21 kWh, $3.79 a day, and $114 a month. Across a five-month May-to-September season at light summer use, the heater adds roughly $285 to the year's electricity.
Heat pump vs. resistance: the 5x difference
The single biggest factor in a pool heater's cost is whether it's a heat pump or an electric resistance unit. A resistance heater turns electricity directly into heat at a one-to-one ratio. A heat pump moves existing heat out of the outside air into the water, delivering about five units of heat for every unit of electricity it draws. For the same water temperature, a heat pump uses roughly a fifth of the power.
That gap is the whole story on the bill. The $57-a-month heat pump above would cost about $285 a month as an electric resistance heater doing the identical job, and over $500 a month in heavy shoulder-season use. The catch is weather: a heat pump's efficiency falls as the outdoor air gets colder, which is part of why the same unit costs more to run in April than in July. Below roughly 50°F it struggles, and that's where resistance and gas heaters still get used despite the cost.
Tip
Check which type you own
The wattage range and common models
Heat pump pool heaters cluster between 3,500 and 7,500 watts of electrical draw, with 5,000 watts typical for a residential unit. At three hours of daily run time, that range runs from about $40 a month at 3,500 watts to $85 a month at 7,500 watts.
Common residential models land close together. The AquaCal HeatWave SuperQuiet SQ166 at 5,000 watts costs about $57 a month. The Hayward HeatPro W3HP21404T at 5,200 watts runs about $59. The Pentair UltraTemp 140 HP at 5,400 watts runs about $61. The wattage on the nameplate is the input power, not the heat output. A bigger number means a faster heat-up and a higher hourly cost, not a less efficient unit.
Same heater, different states
A 5,000-watt heat pump on a three-hour summer schedule uses about 315 kWh a month no matter where the pool sits. The rate is the only variable:
Louisiana (12.44¢/kWh): $39. Texas (14.80¢/kWh): $47. US average (18.05¢/kWh): $57. New York (24.40¢/kWh): $77. California (31.01¢/kWh): $98. Hawaii (39.79¢/kWh): $125.
A pool owner in Hawaii pays 3.2 times what a pool owner in Louisiana pays to keep the same water at the same temperature with the same heater. Every state's 2026 residential rate is in the state rates guide.
The levers that cut the bill
Three levers move pool heating cost, and the biggest one is a sheet of plastic. A solar cover cuts heater runtime 50 to 70 percent by stopping evaporation, which is where most pool heat escapes. That turns a $57 month into $17 to $28, and a $120 to $180 cover pays for itself in the first season.
Lowering the setpoint helps next. Dropping the target temperature 4°F cuts heating energy 15 to 25 percent, about $9 to $14 a month. Most pools are heated warmer than anyone in them needs. 80°F instead of 84°F is rarely noticed in the water and always noticed on the bill.
Season length is the third. A heater that runs May through September costs five months of the numbers above. Stretching the season into April and October with a heat pump means running it in colder air where its efficiency is lowest, so each added shoulder month costs more than a summer month, not less.
Where the pool heater lands on your bill
A pool with a single-speed pump and a heat pump heater adds about $144 a month to a summer electric bill: roughly $87 for the pool pump and $57 for the heater. The pump is the steadier load. The heater swings with the weather and whether the cover is on. Together they put a heated pool among the most expensive appliances to run, above the dryer and rivaling central air.
Hot tubs run on the same math at a smaller scale. Less water, but often heated year-round, which can make a spa's annual electricity cost higher than a summer-only pool's.
These numbers use a 5,000-watt heat pump and average run times. Your unit's wattage, your target temperature, whether you run a cover, and your state rate all move the result. The pool heater calculator takes your heater's draw and your state and returns the monthly and yearly cost. If the summer bill jumped and you're not sure the pool is why, the why your electric bill is high walkthrough helps isolate it.