Swimming Pool Heat Pump FAQs (Frequently Asked Questions)
Swimming Pool Heat Pump FAQs
At HeatPumps4Pools, we supply and support swimming pool heat pumps across the UK, including London, Essex, Kent, Surrey, Hertfordshire and the South East.
This FAQ guide answers the most common questions about swimming pool heat pumps in the UK, including installation, running costs, sizing and servicing. Our experts provide advice for domestic and commercial pools throughout the UK and Europe.
Our team regularly helps pool owners across London, Essex, Kent, Surrey and the wider UK choose the right heat pump
Heat Pump Basics
A swimming pool heat pump works by extracting heat from the surrounding air and transferring it to your pool water using a refrigeration cycle. A fan draws air into the unit, the heat is absorbed by a refrigerant and compressed to increase its temperature, and the heat exchanger transfers that heat to the pool water. Because the system moves heat rather than generating it, it can produce around 5–7 units of heat for every unit of electricity used.
For more information see our How they work page
The cost of running a swimming pool heat pump in the UK depends on the pool size, desired temperature, and outside air temperature. Because heat pumps transfer heat from the air rather than generating it directly, they are very efficient. Most modern pool heat pumps produce around 5–7 units of heat for every unit of electricity used. For many UK pools, this means running costs are significantly lower than gas or electric resistance heaters.
The electricity used by a swimming pool heat pump depends on the size of the unit and how often it runs. Smaller domestic pool heat pumps may use around 1–2 kW while running, while larger units can use more. Because heat pumps are highly efficient, they deliver several times more heat energy to the pool than the electricity they consume, making them one of the most economical ways to heat a swimming pool.
The time it takes to heat a swimming pool depends on the pool size, starting water temperature and the power of the heat pump. Typically, a correctly sized heat pump can raise the pool temperature by around 1–2°C per day. Once the desired temperature is reached, the heat pump mainly works to maintain the temperature rather than heat the pool from cold.
Yes, swimming pool heat pumps work very well in the UK climate. Heat pumps extract heat from the surrounding air, even when temperatures are relatively cool. Modern pool heat pumps can operate efficiently in outdoor temperatures as low as 5–10°C, making them ideal for extending the UK swimming season from spring through autumn.
Most outdoor pools in the UK are heated from spring through autumn, but a heat pump can operate throughout the year depending on the model and weather conditions. Some high-performance heat pumps (our Pro and Edge range) can run in colder temperatures all year round, although efficiency decreases in very cold weather. Indoor pools can usually be heated all year round with a suitable heat pump system.
A high-quality swimming pool heat pump typically lasts 10–15 years or more when properly installed and maintained. Regular servicing, good airflow around the unit and correct pool chemistry all help extend the lifespan of the system.
Modern swimming pool heat pumps are designed to operate quietly. Most units produce around 40–50 decibels, which is similar to normal background conversation. Noise levels vary depending on the model and fan speed, and many inverter heat pumps are especially quiet because they can run at lower speeds once the pool reaches the desired temperature.
In most cases, swimming pool heat pumps do not require planning permission in the UK because they are classed as standard outdoor equipment. However, installation should still follow manufacturer guidelines and local regulations. If the unit is being installed close to neighbouring properties or in a conservation area, it may be worth checking with the local planning authority.
A swimming pool heat pump can extend the UK swimming season by several months. Many outdoor pools that would normally only be usable in midsummer can be comfortably heated from April through October with the right heat pump and a good pool cover. This allows pool owners to enjoy warmer water temperatures for much longer each year.
If you have an existing heater (eg gas, oil, electric etc), then we recommend that you install the heat pump alongside your existing heater.
This will allow you to run both the heat pump and the existing heater if required for a rapid pool heat up, or to provide a backup heater in case the heat pump develops a fault (unlikely). You can also switch to your existing heater when the air temperature becomes too cold for the heat pump to operate efficiently eg right at the end of the season.
If you want to install the heat pump alongside your existing heater, then the water should flow through the heat pump and then the existing heater before returning to the pool for maximum efficiency
Pool heat pumps generally fall into two types:-
- Inverter driven
- On-Off
Inverter driven heat pumps are a newer generation of heat pumps. They are variable speed which allows the fan and compressor to run at different speeds according to the demand from the pool.
On/Off heat pumps can only run at 100% or turn off. They are not variable speed.
The advantage of inverter heat pumps over on/off models is:-
1. More efficient = lower running costs: When inverter heat pumps run at reduced speed their efficiency (COP) rises drastically. Inverter driven heat pumps can have efficiencies (COPs) of up to 14.
This means that for every 1kw of power used, they can return up to 14kw of heat to the pool. The maximum COP for on/off heat pumps is around 5 to 6
2. They are generally much quieter as they do not need to always run at 100%. Once the pool reaches the desired temperature, the inverter driven heat pump can slow itself down and run at a reduced speed eg 30%. When running at a reduced speed, the noise is significantly reduced.
3. Built in “soft-start”. When inverter heat pumps start, they gradually increase their speed from zero up to the required running speed. This gentle start up avoids the power “spike” that can be encountered with on-off type heat pumps.
This “soft-start” feature of inverter driven heat pumps prevents issues such as the house lights flickering when the heat pump starts or electrical breakers tripping on the consumer unit.
At the moment, both on/off and inverter driven heat pumps are available.
Just like the boiler in your house, the heat pump will run for different amounts of time each day depending on the weather.
On warm summer days when the pool is up to temperature, the heat pump may not need to run at all. Whereas on cooler days, the heat pump may run for a few hours.
In extremely cold weather (eg below +5c) the heat pump may need to run for 12 hours a day or more.
When you keep a solar cover on your pool, this will give the pool some heat gain on warm days and will supplement the heat pump.
As the weather gets colder the heat pump will need to run for longer.
You can control how long the heat pump runs for each day by using a time-clock on your pool pump.
Other factors that affect how long the heat pump will run for each day include:-
- The power of the heat pump – a more powerful heat pump will heat the pool more quickly and so will switch off sooner than a smaller heat pump
- How well insulated your pool is
- If you have a high water table around your pool, then this will drain away the pool heat and cause your heat pump to run for longer to replace the lost heat
- The pool water temperature that you require – a higher pool water temperature will need the heat pump to run for longer to maintain the temperature
- Pool cover – an uncovered pool will lose 2-3 times as much heat as a covered pool
As a guide, on warm summer days the heat pump would typically run for between 0-3 hours
On cooler days between 3-8 hours should be sufficient but this depends on the factors mentioned above
See our Savings page.
There is also a calculation on the savings page showing how a large 32kw heat pump costs only £3.33 per day to run !
Smaller heat pumps will cost less than this to run.
There are many factors that should be considered when sizing a heat pump for your swimming pool.
At HeatPumps4Pools we gather the information on how you wish to use your pool and take into account a wide range of factors so that we can give you a heat pump that will meet and exceed your requirements.
If you would like us to recommend suitable heat pumps for your pool, then please complete our Heat Pump Sizing Form
this will capture a wide range of information about your pool including:-
- Pool Dimensions (length, width, average depth in feet or metres)
- Swimming season (eg May – Sept, or all year round etc)
- Desired water temperature (28c is typical)
- If the pool is kept covered when not in use (ie with a solar cover or thermal blanket)
- The number of hours per day that the pool is uncovered
- If the pool has a single or 3-phase electrical supply
- Indoor or outdoor pool
- Pool location (eg UK, France, Spain etc please provide address if you would like a shipping quote)
- Existing pool heating system
- Domestic or Commercial use
- If the property is rented or a holiday home
- Above ground or in-ground pool
We will then give you our recommened pool heat pumps.
Of course you can always call us if you prefer to run through this by phone !
We can provide our expertise to consider all of these factors and help you choose the best size unit for your pool.
We therefore recommend that you contact us to discuss the size of heat pump that you require before making a purchase.
Each of our product listings has a sizing chart that shows the maximum number of cubic metres (m3) of water that each heat pump model supports.
As a start, compare the volume of your pool in m3 to the sizing chart. If your pool volume is near the maximum size supported, then choose the next model up.
Always allow some “headroom” with the power of your heat pump. This will ensure that the heat pump can still produce enough heat to maintain your required pool temperature on colder days.
Inverter heat pumps should also be sized larger than “on-off” heat pumps so that the unit can run at a reduced power output to give the maximum efficiency of an inverter driven pool heat pump
For rented properties or holiday homes, it is advisable to oversize the heat pump to allow a faster heat up time before guests arrive. We also have heat pumps with lockable keypads to prevent guests from adjusting the pool temperature.
Feel free to call us and we are more than happy to run through the sizing of your pool heater.
This refers to the type of electrical supply that the heat pump needs.
Most properties in the UK have a stamdard 100A single phase power supply (ie a live and neutral wire) .
Some larger properties or commercial properties in the UK may have a 3-phase power supply
Smaller heat pumps are normally single phase and 3-phase is generally used for larger models, Single phase heat pumps are available up to around 35kw. Over this all heat pumps will be 3-phase models
Single phase power is 220v to 240v and uses one live wire and one neutral wire.
3-Phase power supplies are 380v to 415v and use three live wires (and sometimes also a neutral wire)
If you are not sure what electrical supply you have, ask your electrician to check this before ordering your heat pump.
3-Phase power is more common in mainland Europe eg Portugal, France and Spain than in the UK and is fitted as standard to most new properties in some parts of mainland Europe.
As a guide, for larger heat pumps (eg over 24kw), then if 3-phase power is available in the pool room, it is better to use a 3-phase pool heat pump.
If in doubt, please call us for more advice.
Most of our heat pumps (apart from mini heat pumps like the Hot Splash and Sunspring models) include a water flow switch. This means that they will only operate when your pool pump is turned on and water is flowing through the heat pump.
You can therefore control when your heat pump operates simply by using a time clock on your water pump.
Some heat pump models also have a timer built into the digital control panel. This allows you to turn the heat pump on and off at set times independently from the pool pump. Note that the pool pump always needs to be operating for the heat pump to work.
The COP is the Coefficient of Performance. It is the ratio of energy input to output. Eg a unit with a COP of 5 would provide 5 units of heat for every one consumed.
For example a heat pump with a COP of 5 would use about 4kw of electricity and output 20kw of heat (ie 5 x 4kw =20kw).
Bear in mind though that there is no international standard for stating COPs and therefore each manufacturer will state the maximum COP obtainable for their units under optimum temperature and humidity conditions. In reality you may not therefore always acheive the COP rating stated.
This is another reason why you should always oversize your heat pump
Each product listing states the physical sizes of each model.
Not at all, the heat pump needs a solid concrete base or can be laid on paving slabs. The unit then needs an electrical supply and it is best to get a qualified electrician to install this.
The plumbing is straightforward and the pipes are glued together. The heat pump only needs a flow and a return pipe.
You should install 3-valves to create a “bypass”.
The heat pump should be installed after the filter and as the last item before the water returns to the pool.
If you want to install the heat pump alongside your existing heater, then the water should flow through the heat pump and then through the existing heater before returning to the pool
See our Installation section for lots more tips on installing your heat pump
At present, pool heat pumps use either R410a or R32 refrigerant gas to operate.
The refrigerant gas is contained inside the heat pump in a pressurised and sealed circuit. The compressor pumps the refrigerant gas around the refrigerant circuit in the heat pump so that the refrigerant gas can absorb heat from the air and transfer this heat to the heat exchanger in the heat pump to heat your pool water.
Both R410a and R32 gases are environmentally friendly
They are also very efficient and there is virtually no difference in the operating efficiency of the two gases.
R32 is slightly more environmentally friendly than R410a gas and has a lower GWP rating (global warming potential). This is only relevant if the refrigerant gas were to leak into the atmosphere. Under normal operation, the refigerant gas remains in the sealed refrigerant circuit – like your fridge and should never leak.
The disadvantage of R32 gas is that is is highly flammable and also runs at a higher pressure than R410a. Many airlines therefore will not carry heat pumps that contain R32 gas whereas they will carry those with R410a gas.
Both gases are well serviced and maintained by engineers.
As there is no operating difference between the two gases and they are both well supported, we believe that it should not be a major factor in selecting a pool heat pump.
Choosing & Locating My Heat Pump
Most swimming pools are heated to between 26°C and 30°C, depending on personal preference. Outdoor pools in the UK are commonly maintained around 27–28°C, which provides comfortable swimming temperatures while keeping heating costs reasonable. The ideal temperature may vary depending on whether the pool is used for relaxation, exercise or family swimming.
Yes, however if you are planning to heat your pond through the winter months, then we recommend the Thermotec Inverter Pro range of heat pumps as they work down to -15c.
See our Koi Page for more information on using heat pumps on koi ponds.
No, all of our pool heat pumps have titanium heat exchangers which are resistant to damage from salt, chlorine or bromine used in pools.
In fact salt pools generate chlorine from the salt water and so are effectively the same as chlorine based pools. Only the method of generation of the chlorine is different.
Mini heat pumps (eg Hot Splash) can be plugged into a standard 13A socket.
For larger models, we recommend that armoured cable is used to run the electrical supply to the heat pump.
Armoured cable provides protection from the cable being accidentally damaged and is therefore safer than standard electrical flex cable.
The heat pump should be connected to an RCD device for safety reasons.
Larger heat pumps will draw more than 13A and so a dedicated electrical supply may be required.
It is best to get a qualified electrician to connect your heat pump to the electirical supply. The electrician will also ensure that the heat pump has a proper earth
No, all of our heat pumps are designed to go outdoors and are weatherproof.
They will operate perfectly well in all weather conditions including heavy rain and wind etc.
We recommend that you cover your heat pump with one of our specially designed winter covers during winter when the heat pump is not in use. This will give your heat pump some additional protection against the weather.
For indoor pools, it is possible to put a heat pump inside the pool enclosure or in a plant room.
In order to do this, the air expelled from the heat pump is blown out of the building by using a through the wall vent kit. (this is only available for some models of heat pump)
A grille, preferably at the other end of the building would allow fresh air to enter the building to replace the air being blown out.
This method will blow the moist pool air out of the building helping to dehumidify the air. The heat pump will gain some benefit from using the warmer pool room air.
The disadvantage of this method is that the air in the pool room will soon be the same temperature as the outside air.
This is not normally desirable for an indoor pool, particularly in winter !
For this reason, it is normally best to put the heat pump outdoors and use seperate dehumidifiers to dry and warm the pool room air.
We sell “all-in-one” type units (eg the Heatstar Gemini) that can provide pool water heating, dehumidification and air heating.
Please contact us for more information.
You can put a heat pump under a tree as long as the tree is more than 2-3 meters above the heat pump.
This is so that the air coming out of the heat pump (on vertical fan models) does not hit the leaves of the tree and then recirculate back into the heat pump. This would cause reduced efficiency.
While the heat pump is operating, the fan will prevent leaves from entering the heat pump.
In the winter, we recommend that you cover the heat pump using one of our specially designed winter covers.
This will prevent leaves from entering the heat pump in Autumn.
Absolutely ! It is almost compulsory to use a solar cover when using a heat pump to heat your pool.
A solar cover provides several benefits:-
- It can heat the pool on its own by up to 8 degrees C
- It reduces water evaporation by 98%
- It acts as an insulation layer and greatly reduces heat loss
- It reduces pool chemical consumption by up to 30%
- It prevents leaves etc from entering the pool
- It saves you money by reducing your heating costs
- Reducing your heating costs will also reduce your carbon footprint
Not using a solar cover is like not insulating the loft in your house. As your heat pump puts heat into the pool, it will be lost into the air when a solar cover is not used.
An uncovered pool will lose about 2-3 times more heat than a covered pool.
Covering the pool is particularly important at night as the air temperature will drop causing a temperature difference between the pool water and the air.
The temperature difference will cause your pool to lose heat at a greater rate than during the day.
We recommend that you keep a solar cover on the pool at all times when the pool is not in use.
The solar cover will work in conjunction with your heat pump to make an efficient combination for heating your pool and minimising energy requirements.
We sell good quality solar covers and rollers
see Solar-Covers
We recommend that you cover your heat pump during the winter. However, you must use a suitable cover. The cover must allow the heat pump to breathe so that mositure and condensation can escape, otherwise corrosion can occur to the components in your heat pump causing permanent damage.
We sell a special range of heat pump winter covers that are custom made for each heat pump model and incorporate ventilation mesh panels to allow air circulation.
Smaller heat pumps can be disconnected and carried into a garage or shed for the winter.
Generally not. We would not advise installing a heat pump in a greenhouse.
Whilst this may seem like a good idea, the benefits are minimal.
This is because heat pumps have quite powerful fan motors and transfer a lot of air.
Within a few minutes of operating, the heat pump will have extracted all of the air in the greenhouse.
You also need a vent to allow fresh air to enter the green house to replace the expelled air.
Within a couple of minutes the temperature of the air in the greenhouse will be the same as the external air.
The air is not in the greenhouse for long enough to warm sufficiently to provide much benefit.
If the air flow to the heat pump is restricted, it may in fact cause lower performance.
Heat pumps normally work best outdoors with a good supply of fresh air.
Most heat pumps should be installed outdoors as they require a good flow of fresh air to operate properly. Some models can however be installed in a pump-house or plant room using the through the wall ducting kit or by cutting a hole through the wall of the plant room to allow the air to be blown outside
A permanent grille must then be installed in the opposite wall of the plant room to allow fresh air to enter the plant room at the same rate as it is leaving.
Generally there is no advantage to putting a heat pump inside a plant room other than to protect it from the weather and possibly for aesthetic reasons.
There are not normally any performance advantages from putting a heat pump inside a plant room. Any surplus heat in the plant room will be expelled within a couple of minutes of the heat pump being turned on and fresh air drawn in from the outside. This causes the temperature inside the plant room to become the same as the outside air temperature negating any performance benefit
Feel free to call us for more advice on this topic
Please see our Installation Tips page for more information
Most units have 50mm pipe outlets. They are normally also supplied with 50mm to 1.5″ adaptors as 1.5″ is the most common size of pipe in the UK.
In Europe, 50mm is the most common size of pipe.
Each heat pump listing states the pipe outlet size
We can supply adaptors to go to different pipe sizes if required.
Digital pool heat pumps have an electronic control panel that allows more accurate temperature setting, simpler operation and, on some models, built-in timers or diagnostic information. Analogue models use more basic manual controls, such as dials or switches, and are generally simpler in design. For most pool owners, digital models offer greater convenience and easier day-to-day use.
Shopping With Us
HeatPumps4Pools is a UK-based specialist supplier of swimming pool heat pumps and pool heating equipment. The company is based in Basildon, Essex, and supplies pool heat pumps, heaters and related equipment to customers across the UK and Europe.
Founded in 2011, HeatPumps4Pools focuses on providing energy-efficient heating solutions for domestic and commercial swimming pools. The company offers a wide range of pool heat pumps from leading manufacturers, along with technical advice, sizing support and after-sales service.
In addition to supplying heat pumps, HeatPumps4Pools also provides equipment for indoor pools, including dehumidification and air-handling systems, and distributes several specialist heat pump brands throughout the UK and Europe.
HeatPumps4Pools is based in Basildon, Essex, and supplies swimming pool heat pumps to customers across the UK and Europe. The company offers a wide range of energy-efficient pool heat pumps along with expert advice on selecting the right unit for your pool size, location and heating requirements.
Yes our prices include VAT and are the total amount payable including free UK delivery.
Our VAT registration number is 114 3502 61
Our prices are some of the cheapest on the internet and we always aim to provide highly competitive prices.
However if you see the same product cheaper elsewhere, then please let us know and we will always try to match or beat any pricing you have seen
The units are delivered on a lorry with a tail lift. The units are on a pallet and will only be delivered to your driveway. You must arrange to carry the unit to where you require your pump to be located. Note that the units are heavy and will require two or three people to move them safely.
Yes, we can ship to anywhere in UK, mainland Europe and beyond.
We regularly send heat pumps to France, Spain, Portugal, Czech, Netherlands etc
We have sent units as far as Egypt and Zimbabwe
Please email us with your required heat pump model and address and we will get a competitive shipping quote for you.
Each product listing states the warranty offered.
Most of our new heat pumps include an on-site parts and labour warranty.
All heat pumps shipped outside the UK are supplied with a parts-only warranty. Outside the UK you will need to employ a local contractor if required and we will courier any necessary spare parts to you