Swimming Pool Heat Pumps

“Just to let you know I have been researching our electricity bills and it cost us £240 to heat our pool in 2015 as opposed to 1 – 2 whole tanks of oil which would have cost about £800. Very happy with that!” – Verity

There are many ways to heat your swimming pool, gas and oil boilers, electric in-line heaters, solar panels and even wood burners, however, these methods can prove to be expensive and inefficient.

An air source heat pump absorbs ‘free’ heat from the surrounding air and transfers this ‘free’ heat to your swimming pool water, for each kW of energy consumed by your heat pump, up to 6kW of heat will be transferred to your pool, making a heat pump up to 80% more cost effective to run and kinder to the environment.

For more information on how a heat pump works, how much it costs to run a heat pump or where your heat pump should be install please look at the frequently asked questions below.

pool-heat-pump-work

How does a swimming pool heat pump work?

Swimming pool heat pumps utilise the sun’s ‘free’ heat by collecting and absorbing energy from the outside air.

This energy is then transferred to your swimming pool water. Heat transfer always occurs from a region of high temperature to another region of lower temperature.

Step One:

The large fan on the heat pump draws in outside air across the surface of the evaporator.

Step Two:

The liquid refrigerant within the evaporator coil absorbs heat from this outside air and the refrigerant ‘boils’ and becomes a gas.

Because the liquid refrigerant is colder than the surrounding air it can still absorb heat at zero degrees and below.

Step Three:

The warm gas passes through the compressor where it is compressed to form a very hot gas.

Step Four:

The ‘heat exchange’ occurs in the condenser as the hot gas gives up heat to the cooler swimming pool water circulating through the coil. The pool water becomes warmer and the hot gas cools down as it flows through the condenser coil.

Step Five:

The refrigerant gas returns to its liquid form and after passing through the expansion valve the whole process begins again.

pool-heat-pump-cycle

How much does it cost to run a swimming pool heat pump?

A swimming pool heat pump could save you up to 80% on your pool heating costs.

For every kW of energy consumed by a heat pump up to 6 kW of heat is returned to the pool, making it a very efficient way to heat your pool compared with boilers or in-line heaters.

The coefficient of performance or COP is a ratio of heating to electrical energy consumed, higher COPs equate to lower operating costs.

It is important to remember that because heat pumps extract heat from the surrounding air, the higher the air temperature the more efficiently a heat pump can operate and the higher the temperature that can be achieved in your pool water.

At an ambient air temperature of 25°C the COP will be 5-6, meaning that for every £1 spent running the heat pump between £5 and £6 of heat will be returned to your pool.

At an ambient air temperature of 15°C a heat pump will have a COP of around 4-5, meaning that for every £1 spent running the heat pump between £4 and £5 of heat will be returned to your pool.

At an ambient air temperature of 10°C the COP will be around 3, meaning that for every £1 spent running the heat pump £3 of heat will be returned to your pool.

Below 10°C the heat pump will still extract heat from the air but the capacity to heat will be reduced and the heat loss from your pool will increase, this balance point determines at which point you can no longer heat your pool.

costs

Will a larger heat pump cost more to run?

The running costs will be almost the same for an 18kW heat pump compared with a 13kW heat pump, however the speed at which you can heat your pool water will be faster.

For example, if your pool required 100kW of energy to maintain your temperature at X (under ideal air temperatures).

The 18kW heat pump with a power input of 2.51kW will run for 5.6 hours to heat your pool (100/18kW). This means you would consume approximately 14kW of energy (5.6 hrs x 2.51kW).

The 13kW heat pump with a power input of 1.86kW will run for 7.7 hours to heat your pool (100/13kW). This means you would consume approximately 14.3kW of energy (7.7 hrs x 1.86kW)

Whilst the energy consumption is almost the same the larger heat pump can heat up the pool nearly 30% quicker.

This is turn means you have more flexibility to chose what time of day you heat your pool so you can maximise your COP rather than having to run the heat pump for longer when the air temperature maybe cooler.

pool-heat-pump-weighing-up

Can I use a swimming pool heat pump all year round?

Modern swimming pool heat pumps are very efficient meaning you can enjoy a longer swimming season.

Heat pumps are at their most efficient in ambient air temperatures in excess of 15°C, meaning manufacturers recommend a season running from late April to the end of September.

Extended season heat pumps have a defrost function that allows them to operate in colder air temperatures (normally below +8°C) and all season heat pumps will operate in temperatures down to -10°C allowing you to use them all year round.

It is worth noting that while heat pumps can run in lower air temperatures it does mean a reduced kW output and therefore a reduced heating capacity, which means that you may not be able to achieve the same water temperature you would achieve in warmer weather. It is also worth noting that heat loss from your pool will also increase the lower the outside temperature.

All heat pumps have a balance point – the point at which the heating capacity matches the heating requirement – below this point the heat pump will no longer be able to heat your pool to the desired temperature. By over specifying your heat pump you can move the balance point to achieve an increase in your heating capacity, this in turn will allow you to achieve a higher temperature or extend the season of use.

As air temperature falls, heating capacity decreases and heat loss increases.

There are a number of variables that can alter the balance point such as pool insulation or pipework, for this reason all manufacturer quoted figures are based on averages, therefore a heat pump may not always be suitable for a particular application or set up or may not achieve the maximum heating temperature claimed.

Please note: We recommend that you should keep your pool covered when you are not swimming, 80% of pool heat loss occurs from surface evaporation. If you have an above ground pool it is especially important to keep the pool covered as these pools are not as well insulated against heat loss. If your pool did not come with a cover supplied then a separate solar cover would be a worthwhile investment, otherwise, any heat generated by the heat pump will be lost through surface evaporation and you will struggle to achieve your required temperature.

balance-point

Where should I install my swimming pool heat pump?

Swimming pool heat pumps extract heat from the surrounding air so they should always be installed outside.

Heat pumps should be located a minimum of 0.3 metres to the rear and 0.7 metres to the sides from walls, fences and dense vegetation and have a two and a half metre clearance at the front to allow proper air flow around the unit, if the cooled air that the heat pump expels is not allowed to escape, the build up of cooler air around the heat pump will reduce its ability to heat as effectively.

The heat pump should be sited on a solid base using the supplied anti-vibration feet.

Heat pumps are designed for use outside and constructed for durability and longevity, heat pumps have a variety of outer casing materials including enamel-coated steel, corrosion resistant ABS and stainless steel.

All heat pumps come supplied with a winter cover to protect them from the worst of the weather, however, the heat pump cannot be operated with the cover on. Our all season heat pumps feature a modern ABS cabinet making them resistant to weather.

The use of a highly efficient, low sound rotary or scroll compressor, a low noise fan and an oversized heat exchanger, makes the heat pumps extremely quiet in operation, the noise level on most heat pumps measures between 50dB and 60dB at one metre (60dB is equivalent to a normal conversation at the same distance).

Most heat pump installations incorporate a bypass kit in the pipework. The bypass kit (which consists of three ball valves and two tee junctions) allows you to control the flow of water to your heat pump, making it possible to winterise or maintain your heat pump without having to affect the flow of water to your swimming pool. We can supply bypass kits to fit most sizes of pool pipework.

Please note: We recommend that you should keep your pool covered when you are not swimming, 80% of pool heat loss occurs from surface evaporation.

If you have an above ground pool it is especially important to keep the pool covered as these pools are not as well insulated against heat loss.

If your pool did not come with a cover supplied then a separate solar cover would be a worthwhile investment, otherwise, any heat generated by the heat pump will be lost through surface evaporation and you will struggle to achieve your required temperature.

pool-heat-pump-install

What are the benefits of inverter technology?

Inverter heat pumps use a variable speed compressor motor, the motor speeds up and slows down as needed to achieve and maintain the required temperature, the result is that the desired temperature will be reached more quickly and maintained more efficiently.

Fixed speed motors reach the desired temperature more slowly as the output is fixed, once the temperature is reached they maintain the temperature by switching the motor on and off. By varying the output an inverter heat pump can speed up the time taken to achieve the initial temperature and thereafter maintain a constant temperature without the need to keep stopping and starting the compressor to control output.

Our range of inverter pool heat pumps have a C.O.P. of up to 13, meaning that for each kW of energy consumed up to 13kW of heat is transferred to your pool (dependent on both air and water temperature). Inverter technology avoids the power wastage of fixed speed motors, making an inverter heat pump up to 30% more energy efficient and quieter to run.

Choosing the right heat pump for your swimming pool

A heat pump is an investment that chosen correctly will reward you with many years of service and will also pay for itself in the savings you make in running costs.

Sizing a heat pump for your pool is relatively simple, however just because a pump is the correct size it does not mean it is the right heat pump for you.

When sizing a heat pump for you we will not simply ask how big your pool is, instead we will ask you a series of questions about how and when you use your pool, what temperature you want to achieve, what other equipment you have connected, what pipework is involved and where the equipment is located – this will help us to build a picture and advise you on the correct heat pump for your needs.

Many of our customers choose to over spec their heat pumps, while the initial outlay is higher the heat pump will provide additional heating capacity providing an extended swimming season or increased water temperature – advantages many of our customers believe outweigh the additional investment.

Talk to us about pool heat pumps

If you would like to talk to us about a heat pump for your pool give us a call on 01842 819130, we are more than happy to talk through your requirements or answer any questions you may have.

We can provide a free no obligation quote and all our stock heat pumps are delivered free on a next working day pallet service (like any item containing refrigerant, heat pumps must always be kept upright, securing a heat pump to a pallet ensures they remain upright during transport).

We also stock pool pumps, pool filter sets, pipework and fittings.