There are many ways to heat your swimming pool, boilers, in-line heaters, solar and even wood burners, however, these methods can prove to be expensive and inefficient.
An air source heat pump absorbs heat from the air and transfers it to your pool water, making a heat pump up to 80% cheaper to run than electric heaters or gas boilers and kinder to the environment.
Should my heat pump be installed inside or outside?
Swimming pool heat pumps extract heat from the ambient air so they should be always installed outside on a solid base using the supplied anti-vibration pads.
To ensure the most efficient operation, heat pumps should be located away from walls, fences and dense vegetation to allow proper air flow around the unit, if cooled air is not allowed to escape, the build up of cooler air around the heat pump will reduce its ability to heat.
Heat pumps are designed for use outside and constructed for durability and longevity, heat pumps have a variety of outer casing materials including corrosion resistant ABS.
The use of efficient, low noise compressors and fans and oversized heat exchangers, makes heat pumps extremely quiet in operation, the noise level on most heat pumps measures between 30dB and 50dB.
Talk to us about pool heat pumps
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.
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 buy a larger heat pump than pool size alone would dictate, while the initial outlay is higher the larger 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.
Frequently asked questions…
What are the clearance distances?
To ensure the most efficient operation, heat pumps should be located away from walls, fences and dense vegetation to allow proper air flow around the unit, if cooled air is not allowed to escape, the build up of cooler air around the heat pump will reduce its ability to heat.
Horizontal units should be placed at least 300mm from a wall or hedge, allowing 700mm to each side, 500mm clearance above the unit and a minimum clearance of 2500mm in front of the unit to allow the fan to expel cooled air.
Vertical units should be placed at least 800-1000mm from a wall or hedge, allowing 800-1000mm to each side and a minimum of 2000mm clearance above the unit to allow the fan to expel cooled air.
Distances may vary by model/manufacturer.
Does my heat pump need to be in full sun?
Air source heat pumps absorb heat from ambient air, a plentiful supply of fresh air is more important than a sunny spot. The heat pump will work in a shaded location as long as there is good airflow.
It is not a problem to locate a heat pump in an exposed or windy location, in fact a windy location that gets full sun would combine good airflow and warm air and increase the efficiency of heating.
What size heat pump do I need?
We have put together a simple to use sizing guide for the ideal size of heat pump we would suggest you need to heat your pool.
Your pool volume can be calculated by multiplying the length x width x average depth.
Average depth can be calculated by adding the depth at shallow end together with the depth at deep end and dividing the total by two – we normally use metric measurements in our calulations.
For Roman End and shaped pools take the measurements at the longest and widest points.
As a general rule of thumb we normally double the volume of above-ground pools when calculating which heat pump you would require, this is to offset the additional heat loss from these pools.
What electrical connections do I need?
All electrical wiring should be carried out by a qualified electrician
Manufacturers recommend that you connect the heat pump to a circuit with a separate MCB (Miniature Circuit Breaker, motor rated type C or D) with the correct fuse. Full installation guidelines can be found in the user manual for each heat pump including the recommended fuse rating and cable size.
Inverter heat pumps have soft start as standard (the graduated starting of the compressor avoids the initial full load current), however the use of a motor rated MCB is still recommended.
Failure to follow the manufacturers guidelines for the correct electrical connection of your heat pump could invalidate your warranty.
What is R32?
Heat pumps contain refrigerant, the liquid refrigerant passes through the evaporator where it absorbs heat from the surrounding air and becomes a gas, the gas passes through the compressor where it becomes a very hot gas and then the heat exchange occurs in the condenser where the heat from the gas is transferred to your pool water and the cooled refrigerant becomes a liquid again. Currently the refrigerant used in swimming pool heat pumps is R410A.
Refrigerants have a Global Warming Potential (GWP) with carbon used as the base, Carbon has a GWP of one. Swimming pool heat pumps have been using R410A since roughly 2006, R410A has a GWP of 2,088 meaning that if one kilogram is released into the atmosphere it would have 2,088 times the harmful effect of one kilogram of carbon.
R32 has a low GWP of 675, making it nearly two thirds less harmful than R410A. R32 is better for the environment, offers higher energy output and higher efficiency so less is required per kW and is safer to handle and use.
Can I wire my filter pump to my heat pump?
Some heat pumps have an additional electrical connection labelled ‘Water Pump’, a common question is can I wire my filtration pump to this connection?
We don’t recommend using the water pump connection if you have a sand filter, this is because heat pumps switch off once the pool is up to temperature, depending on the number of hours of heating required it could mean that your filter pump is switched off before the daily filtration cycle is completed.
Additionally you will not be able to backwash your filter as the flow switch on the heat pump will switch the unit off when it detects no flow.
Therefore we would recommend that your filtration pump has an independent power supply, instead the flow detection on the heat pump will automatically switch the heat pump on and off with the flow of water from your filtration pump.
What is a bypass kit?
A bypass kit allows you to control the flow of water through your heat pump to maximise the transfer of heat to your pool water, the bypass kit also allows you to easily winterise or maintain your heat pump without having to affect the flow of water to your swimming pool.
The bypass kit, along with the heat pump is located in your return pipework after the filter pump, but before any chemical dosing equipment, and normally consists of three ball valves and pipework, two valves are used to adjust the flow to and from the heat pump and the third is used to bypass the heat pump.
Can I use my existing filter kit?
Most heat pumps have a minimum flow rate that is required to enable the efficient transfer of heat, depending on the flow rate of your existing pump and filter you may need to upgrade your existing equipment.
If you are unsure please speak to us first, if your existing pump and filter does not provide sufficient flow rate it could result in your heat pump not achieving the desired temperature or not switching on, the flow sensor in the unit will prevent operation to avoid damage to the heat pump in the event of no or limited flow.
Poorly maintained filter sand (backwashes have not been done regularly or at all) can be a cause of low flow rates, as a rough guide filter sand should be replaced every two years (heavy usage) or five years (low usage).
Can I heat my pool all year?
Dependent on your pool type you can heat all year round with the correctly sized heat pump, if you are interested in heating your pool beyond May to September, please call us and we will be more than happy to match a heat pump to your requirements.
The period you wish to heat for also has a bearing on the speed at which your investment is returned, for example if you only intend to use your pool from May to August it would take a lot longer to see a return on your investment on one of the newer Inverter models, whereas if you intend to heat all year round an Inverter will pay for itself much more quickly.
What does COP mean?
The coefficient of performance or C.O.P. is the ratio of heat output to energy input, a higher C.O.P. equates to lower running costs.
For example, at an ambient air and water temperature of 26°C and a C.O.P. of 6, then for every 1KW of energy consumed by the heat pump 6kW of heat would be output to your pool.
Inverter heat pumps have variable speed compressors allowing them to achieve higher C.O.P.s than fixed speed heat pumps. For example, at an ambient air and water temperature of 26°C and a C.O.P. of 13, then for every 1KW of energy consumed by the heat pump 13kW of heat would be output to your pool.
How does a heat pump work?
Swimming pool heat pumps absorb energy from the outside air and transfer this heat to your 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 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.
What is the cheapest way to heat a pool?
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, with a COP of 5-6, for every 1KW of power consumed by the heat pump between 5kW and 6kW of heat will be returned to your pool.
At 15°C, with a COP of around 4-5, then for every 1KW of power consumed by the heat pump between 4kW and 5kW of heat will be returned to your pool.
Even at 10°C, with a COP of around 3, then for every 1KW of power consumed by the heat pump 3kW of heat will still be returned to your pool, making a heat pump more cost effective than other methods of heating
As the ambient temperature falls the heat pumps capacity to heat will be reduced and the heat loss from your pool will increase, once this balance point is reached you will no longer be able to heat your pool. It is important to note that the minimum air temperature a heat pump will work down to varies between models.
Do larger heat pumps cost more to run?
The cost of heating a pool with a larger heat pump will be almost the same as with a smaller heat pump from the same range, while the larger heat pump has a higher power input it can heat the water in a shorter period of time.
For example, if your pool requires 100kW of energy to maintain your temperature at X (under ideal air temperatures). Then an 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). A 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 means that you can maximise your COP by heating during the warmest part of the day rather than running the heat pump over a longer period when the air temperature maybe not be at its highest.
Can I heat my pool all year round?
Heat pumps are at their most efficient in ambient air temperatures in excess of 15°C.
Summer season only heat pumps will not operate at temperatures below +8-10 degrees. 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.
While heat pumps can still heat at 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. The heat loss from your pool will also increase at lower air temperatures.
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. With a larger 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.
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: Your pool should be kept covered when not in use as 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.
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 full inverter pool heat pumps have a C.O.P. of up to 17, meaning that for each kW of energy consumed up to 17kW 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 than fixed speed heat pumps.
When an inverter heat pump turns on, the current starts from 0 A and goes up slowly to the rated current over a couple of minutes, this is often referred to as soft start. By comparison the starting current of on/off heat pumps can be up to five times the rated current.
