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.

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.

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.

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.

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*

*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*

*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.

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.