Swimming Pool Heat Pumps and Pool Heaters


At HeatPumps4Pools, we specialise in swimming pool heating and we can help you select the best method for heating your pool.

There are several common options available for heating a swimming pool. These include:-

  • Swimming Pool Heat Pumps
  • Gas boilers
  • Oil Boilers
  • Heat Exchangers
  • Electric Pool Heaters

The Benefits of Using  Heat Pump to Heat Your Pool

Put simply a heat pump normally offers the lowest cost method of heating your swimming pool.

Heat pumps extract FREE heat from the outside air by using refrigeration technology.

They have a built in heat exchanger which transfers the heat captured from the air into the pool water. The heat exchangers are normally made of titanium so that they are resistant to the corrosive effects of pool chlorine on most metals.

Swimming Pool Heat Pumps are Highly Efficient

At HeatPumps4Pools., the swimming pool heat pumps that we sell are highly efficient and have very high COPs

The COP is the ratio of the input power to the output heat to the pool.

Most swimming pool heat pumps deliver at leadt 5-6kw of heat to the pool for every 1kw of electricity they use.

Modern inverter driven pool heat pumps can deliver up to 14kw of heat to the pool for every 1kw of electricity used.

This makes the efficiency of a swimming pool heat pump up to 1400% whereas an electric heater is only 1:1 between input and output (100%)

Inverter Driven Swimming Pool Heat Pumps

The latest swimming pool heat pumps now use inverter technology.

Inverter technology allows the fan and the compressor in the pool heat pump to run at variable speeds.

The heat pump can therefore adjust its output to exactly match the demand from the pool.

Once the swimming pool has reached its desired temperature, an inverter driven swimming pool heat pump will reduce its output down to typically around 25% to 50% of its maximum power.

When the inverter driven swimming pool heat pump is running at reduced power, the COPs can reach around 14.

This means that for 1kw of electricity used, up to 14kw of heat can be  delivered to the pool.

No other method of swimming pool heating can deliver such high efficiency

At HeatPumps4Pools, we sell a wide range of swimming pool heat pumps that we consider to offer the best combination of price, performance, warranty and after-sales support (eg spare parts availability).

Our range includes all of the leading brands of pool heat pumps including:-

  • Thermotec Inverter
  • Calorex
  • Aquacal
  • Angel Fire
  • Hot Splash
  • Sunspring
  • Waterco
  • Astral
  • BWT
  • Heatseeker
  • Garden Pac
  • etc

We are happy to help you select the best option for your pool and budget. Feel free to call us, email us or use our live chat service.

Electric Pool Heaters

In comparison to electric pool heaters, these are only 1:1 ie 100% efficient. With an electric swimming pool heater, 1kw of electricity consumed delivers 1kw of heat to the pool.

As you can see, electric pool heaters therefore have a much lower efficiency than swimming pool heat pumps and therefore have a mich higher running cost.

Electric pool heaters for above ground pools have a lower initial purchase cost, but a considerably higher running cost.

A 6kw electric pool heater will consume 6kw of electricity to produce 6kw of pool heat.

A heat pump on the other hand would only consume around 1kw to produce 6kw of pool heat

At HeatPumps4Pools, we supply a wide range of electric pool heaters

electric pool heater - nano 3kw

Nano 3kw Plug and Play Electric Pool Heater – click Here for more details

Gas and Oil Boilers

Older gas and oil boilers only have an efficiency of around 60%. Newer condensing style gas boilers can have efficiencies of around 80%, however they still do not compare to the efficiencies of swimming pool heat pumps.

certikin Genie Condensing Boiler

Gas boilers can however be suitable for indoor pools to deliver heat to an all in one unit which can provide pool water heating, air heating and dehumidification of the air in the pool hall.

The advantage of using a gas or oil boiler is that the output is constant regardless of the outside air temperature whereas the output of swimming pool heat pumps is related to the outside air temperature.

As the air temperature falls, the output of a pool heat pump will also fall.

Note that due to the gas boiler regulations, from March 2018. all new gas or oil boilers must be the condensing type with an efficiency of over 80%. Therefore all models with efficiencies of less than 80% are being discontinued.

Please contact us to discuss a suitable boiler for your pool project.

How Swimming Pool Heat Pumps Work

Heat pumps use technology similar to air-conditioning units. They use a fan and compressor to take heat from the surrounding air and transfer it to your pool.

how heat pumps work

The fan blows air out of the unit and in doing so, air is drawn over the evaporator coil (around the outside of the unit on the above diagram)

This then transfers heat from the air to the refrigerant gas inside the refrigerant pipes.

The compressor compresses the refrigerant gas which causes it’s temperature to increase considerably

This hot gas is then passed through a heat exchanger which has the pool water flowing around the hot refrigerant gas causing heat to be transferred to the pool water

Heat Exchanger titanium tubing

pool heat pump spare parts

The Refrigeration Cycle

For every £1 that you spend on electricity with a heat pump, approximately £5 to £14 of heat will go into your pool. The electricity to the heat pump simply powers the fan and compressor. The system takes heat from the surroundng air and transfers it to the pool using the refrigeration cycle.

the heat pump refrigeration cycle


At 1 a unit of electrical energy (you pay for) runs the compressor which sucks evaporating freon gas from the liquid filled evaporator tube. This causes a strong cooling effect (just like sweat evaporates from you skin & cools you off). The gas picks up four units of heat (FREE) from the air flowing over the outside of the evaporator tubes.

At 2 the compressor squeezes this gas, causing its temperature to climb above 200° F (93° C) Result: Five units of heat added to the gas.

At 3 the hot,high pressure gas flows through the inside of the condenser coil. The colder 80° F (26° C) pool water picks up the five units of heat from the freon which cools it down back to a warm liquid.

At 4 the warm liquid is forced through a valve. As it drops in pressure, it rapidly expands and becomes extremely cold liquid .This liquid flows back into the evaporator At 1 where it repeats the cycle

Cost Savings from Using Swimming Pool Heat Pump

Heat pumps can drastically reduce the running cost of your swimming pool

For every £1 that you spend on electricity with a heat pump, approximately £5 of heat energy will go into your pool. (This can rise to £14 for modern inverter driven heat pumps). The electricity to the heat pump simply powers the fan and compressor. The system takes heat from the surrounding air and transfers it to the pool.

pool heating costs

A heat pump is approximately:-

  • 1/2 the cost of Natural Gas
  • 1/3 the cost of Oil or Propane
  • 1/5 the cost of Electric Resistance

These figures were produced BEFORE the fuel price inceases in the UK and so the savings are even greater.

Below is a guide to the costs to heat a pool or pond using different heating methods. This is an average/guide as the cost of heating will vary according to the time of year and the weather, however this still provides a useful illustration of the savings that using a heat pump can bring.

pool heating cost graph, heat pump, gas, oil, electric

How Much Will It Cost to Run a Swimming Pool Heat Pump?

The following is an example of running costs from a Heat Perfector 32kw unit.

This would be for a large pool and smaller heat pumps will be less to run.

The calculations were made in June 2009.

  • Heat Perfector 32kw is rated at 19.3A which is 4.63kw.
  • Typical electricity costs are 9p per kwh (Based on NPower Sign Online 14 Tariff at June 2009)
  • Running costs are therefore 4.63kw x 9p = 41.6p per hour
  • Assuming the heat pump runs for an average of 4 hours per day (often less in summer) this would cost
  • 4hrs x 41.6p/hour = £1.66 per day

So running a 32kw heat pump for 4hrs a day would cost approx £1.66 per day – less than a sandwich !

This equates to £50.49 per month (£1.66 x 365 / 12) although for an outdoor pool, you would only run the heat pump in the summer months, say April to September

Like your house boiler, the amount of time that the heat pump needs to run for mainly depends on the weather.

In very warm weather and when used in conjunction with a solar cover, the heat pump may not need to run at all.

In colder weather (eg below 15c) the heat pump may need to run for between 4-8 hours on average.

Of course with a good summer, your pool heating costs will be lower than on a poor cold summer.

for all enquiries, please contact us at enquiries@heatpumps4pools.com

Free Pool Heating Assessment

At HeatPumps4Pools, we are happy to provide a FREE assessment of the best method of heating your indoor, outdoor or above ground pool.

Please Contact Us to discuss your requirements

Or Please use our Heat Pump Sizing Form