Heat Pump Swimming Pool Heaters (2024)

A heat pumpis a device that uses a small amount of energy to move heat from one location to another. Heat pumps used for heating pools transfer heat from the outdoors into the water. Unlike gas heaters that require natural gas or propane, they use heat that is already available and just move it from one place to another, thereby using a cleaner heat via electricity, producing no carbon monoxide.

Why Use a Heat Pump for Water Heating?

Reason #1: You Want to Use Your Pool Year-Round

Heat pumps are perfect for use in warmer climates! Heat pumps are most efficient when they’re heating outdoor air that’s above 50 degrees Fahrenheit. Anything below 50 and a heat pump does start to lose efficiency.In fact, heat pumps work more efficiently the warmer the air temperature gets.

Reason #2: Heat Pumps Yield Better Energy Savings

If you want to save on your energy bill,heat pumps provide great value.

Think of a gas heater as a muscle car and a heat pump as a bike. A gas heater will definitely heat your pool faster, but you’ll pay a price for it when the energy bill comes. On the other hand, a heat pump will provide an even and consistent heat once it reaches your ideal temperature, operating with much less effort.The U.S. Department of Energy confirmsthat if you run an average heat pump year-round at 85 degrees, you’ll experience up to $400 a year in energy savings.

Reason #3: Some Heat Pumps Can Cool Your Pool, Too!

If you’re in the market for a heater, you’re probably already invested in your pool, and making it an enjoyable experience. Why not go the extra mile?

A premium heat pump model won’t just heat your pool, but also keep the water cooler when the weather is too hot outside.

How a Heat Pump Pool Heater Works


As the pool water circulates through the pool pump, it passes through a filter and the heat pump heater. The heat pump heater has a fan that draws in the outside air and directs it over the evaporator coil. Liquid refrigerant within the evaporator coil absorbs the heat from the outside air and becomes a gas. The warm gas in the coil then passes through the compressor. The compressor increases the heat, creating a very hot gas that then passes through the condenser. The condenser transfers the heat from the hot gas to the cooler pool water circulating through the heater. The heated water then returns to the pool. The hot gas, as it flows through the condenser coil, returns to liquid form and back to the evaporator, where the whole process begins again.

Higher efficiency heat pump pool heaters usually usescroll compressorsversus thereciprocal compressorsof standard units.

Heat pump pool heaters work efficiently as long as the outside temperature remains above the 45ºF–50ºF range. The cooler the outside air they draw in, the less efficient they are, resulting in higher energy bills. However, since most people use outdoor pools during warm and mild weather, this usually isn't an issue.

Selecting a Heat Pump Pool Heater

Heat pump pool heaters cost more thangas pool heaters, but they typically have much lower annual operating costs because of their higher efficiencies. With proper maintenance, heat pump pool heaters typically last longer than gas pool heaters. Therefore, you'll save more money in the long run.

When selecting a heat pump pool heater, you should consider its:

  • Size.
  • Efficiency.
  • Costs.

Sizing a Heat Pump Pool Heater

You should have a trained pool professional perform a proper sizing analysis for your specific pool to determine pool heater size.

Sizing a heat pump pool heater involves many factors. Basically, a heater is sized according to the surface area of the pool and the difference between the pool and the average air temperatures. Other factors also affect the heating load for outdoor pools, such as wind exposure, humidity levels, and cool night temperatures. Therefore, pools located in areas with higher average wind speeds at the pool surface, lower humidity, and cool nights will require a larger heater.

Heat pump pool heaters are rated by Btu output and horsepower (hp). Standard sizes include 3.5 hp/75,000 Btu, 5 hp/100,000 Btu, and 6 hp/125,000 Btu.

To calculate an approximate heater size for an outdoor swimming pool, follow these steps:

  1. Determine your desired swimming pool temperature.
  2. Determine the average temperature for the coldest month of pool use.
  3. Subtract the average temperature for the coldest month from the desired pool temperature. This will give you thetemperature riseneeded.
  4. Calculate the pool surface area in square feet.
  5. Use the following formula to determine the Btu/hour output requirement of the heater:

Pool Area x Temperature Rise x 12

This formula is based on 1º to 1-1/4ºF temperature rise per hour and a 3-1/2 mile per hour average wind at the pool surface. For a 1-1/2ºF rise multiply by 1.5. For a 2ºF rise multiply by 2.0.

Determining Heat Pump Pool Heater Efficiency

The energy efficiency of heat pump pool heaters is measured by coefficient of performance (COP). The higher the COP number, the more efficient. The federal test procedure for heat pump pool heaters sets the test conditions at 80ºF ambient dry bulb, 63% relative humidity, and 80ºF pool water. COPs usually range from 3.0 to 7.0, which converts to an efficiency of 300%–700%. This means that for every unit of electricity it takes to runs the compressor, you get 3–7 units of heat out of the heat pump.

Estimating Heat Pump Pool Heater Costs and Savings

For an outdoor pool, use the following tables to help estimate your annual heat pump pool heatercosts and savings compared to using an electric resistance or agas pool heater.

Table 1 estimates annual heat pump pool heating costs by location, bywater temperature, and with or without using apool cover.

Table 1. Costs by Location of Heating Outdoor Pools with a Heat Pump*

w/ cover1/1–12/31$293$409$559
w/ cover3/1–10/31$49$116$158
w/ cover4/1–10/31$123$191$279
w/ cover4/1–10/31$211$279$395
Los Angeles5/1–10/31$1294$1649$2023
w/ cover5/1–10/31$116$211$327
Kansas City5/1–10/31$974$1274$1615
w/ cover5/1–10/31$198$279$368
New York5/1–9/30$1008$1328$1662
w/ cover5/1–9/30$143$204$273
w/ cover5/1–9/30$143$204$266
w/ cover5/1–8/31$95$136$204
w/ cover5/1–8/31$164$225$320
w/ cover6/1–9/30$136$170$259
San Fran6/1–8/31$1090$1294$1512
w/ cover6/1–8/31$129$225$327
w/ cover6/1–8/31$204$293$382

*Figures based on a 1,000 square foot, outdoor pool heated with an air to water heat pump with an average COP of 5.0 at $.1301/kwh.

Table 2 estimates the savings for every $1000 in annual pool heating costs using a heat pump pool heater compared to using an electric resistance or gas pool heater with an efficiency of 55% (baseline).

Table 2. Annual Savings Comparisons of
Gas and Electric Pool Heaters*

Gas Pool Heater
Electric Resistance

*Based on an electric resistance heated pool, which costs $1,000 per year at an electric cost of $.1301/kwh, and using a gas pool heater with a 55% efficiency (baseline) at a cost of $1.09/therm. A seasonal average COP of 5.0 was used to determine heat pump savings.

Installation and Maintenance

Proper installation and maintenance of your heat pump pool heater can optimize its efficiency. It's best to have a qualified pool professional install the heater, especially the electric hookup, and perform complicated maintenance or repair tasks.

Read your owner's manual for a maintenance schedule and/or recommendations. You'll probably need to tune up your pool heater annually. Because of a heat pump pool heater's many moving and electrical parts, it will probably require periodic service by an air conditioning technician.

With proper installation and maintenance, heat pump pool heaters can last 10 or more years.

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Heat Pump Swimming Pool Heaters (2024)


Are heat pump pool heaters worth it? ›

A gas heater will definitely heat your pool faster, but you'll pay a price for it when the energy bill comes. On the other hand, a heat pump will provide an even and consistent heat once it reaches your ideal temperature, operating with much less effort.

What are the cons of a heat pump pool? ›

Cons of Heat Pumps for Pools

These units are less effective at temperatures below 50º F. Another drawback is that larger pools will take longer to heat up than they would with a gas heat pump. Owners will also need to consider that they will need to install a dedicated 50–60 amp breaker to operate a heat pump.

How much can a heat pump heat a pool? ›

A heat Pump, when properly sized, can maintain any desired pool temperature between 80 and 90 degrees, regardless of outside weather conditions. A Heat Pump will work when the outside air temperature is above 45 degrees.

What is the lifespan of a pool heat pump? ›

The toughness of a pool heat pump depends on a variety of factors, such as its quality, how often it is used, its maintenance, and the environmental factors into which it is put. Ordinarily, an appropriately kept up with pool heat pump can persevere for 10 to 15 years.

Should I leave my pool heat pump on all the time? ›

Keeping your pool heat pump running continuously can offer significant advantages. Steady temperatures are not only inviting but they also prevent the thermal shock to the system that can occur with intermittent use.

Should I run my pool heat pump at night? ›

Leaving the pool heat pump on overnight contributes to a more stable pool temperature. If you prefer to enjoy a warm pool first thing in the morning or throughout the day without waiting for the heat pump to catch up, keeping it on during the night can be beneficial.

What is the main disadvantage of a heat pump? ›

Reduced efficiency in cold weather: Effectively extracting thermal energy from outdoor air becomes increasingly difficult as the temperature drops. To overcome this, heat pumps feature a far less efficient backup electric heating element.

Who should not get a heat pump? ›

Heat pumps might struggle in drafty, poorly insulated homes. You might need to upgrade your electrical service to support whole-house electric heating. And it's possible that you'll want to keep (or add) a backup heating system just in case the weather gets so unusually cold that your heat pump can't keep up.

Do pool heat pumps cause pools to lose water? ›

Heated pools do result in more evaporation, so more make-up water is required to refill heated pools than unheated pools. Whether using solar heating, heat pumps, or gas heaters, heated pools do require more water.

Can I install a pool heat pump myself? ›

We recommend having a qualified pool professional or electrician install the heater. Especially for electrical wiring and hookups. Heat pumps need plenty of air circulation and work best outside with plenty of clearance surrounding the unit with no obstructions.

How long does a heat pump take to heat a pool? ›

If you're looking into electric heat pumps, they can roughly take up to 12- 48 hours to heat up the water in your swimming pool, the temperature it can usually get to in that time is around 28 degrees. The Oasis X Series Heat Pumps are specifically designed to extend your swimming season for up to 8 months a year.

How cold is too cold for a pool heat pump? ›

We at AquaCal recommend keeping the following as a rule of thumb when it comes to heat pumps in the winter anytime the average temperature (high and low) is 55°F or higher, your heat pump will work to your expectations.

What is the most efficient type of pool heater? ›


Solar pool heaters are the most cost-effective option that uses the sun's energy to heat your swimming pool water. It uses solar collectors, filter, a pump and a flows control valve to heat the pool in a way that is very economical.

How many hours a day should a pool heat pump run? ›

A properly sized pool heater should heat your pool approximately 1 degree per hour. A pool heater is like the heat in a home. If you swim mostly everyday turn it on, set the thermostat to 83 and leave it on all the time. If you only swim weekends turn it on Friday and off Sunday night.

Do pool heat pumps work in cold weather? ›

Most heat pumps shut down when the outside temperatures go down below 55° degrees, some can continue to operate down to the mid to low 40's, and some can operate in temperatures of mid to low 20's.

Why are pool heat pumps so expensive? ›

The cost to install a swimming pool heat pump is all about the electrical. A pool heat pump requires 220V electrical service and its own 50 amp breaker.

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