Air Source Heat Pump Swimming Pool Heating
A pool heat pump costs £400–£700 per year to run — compared to £1,500–£2,500 for gas and £3,000–£5,000 for electric. Here is everything UK pool owners need to know about the most efficient way to heat a swimming pool.
If you have a swimming pool — or you are planning to install one — heating it efficiently is one of the biggest ongoing costs you will face. An unheated outdoor pool in the UK is usable for perhaps three months of the year. A heated pool extends that to six months or more.
Air source heat pumps are by far the most efficient way to heat a pool. They cost a fraction of what gas or electric resistance heaters use in energy, and they have become the standard choice for pool heating across the UK and Europe.
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How Does a Pool Heat Pump Work?
A pool heat pump works on exactly the same principle as a home heating heat pump — it extracts heat from the outside air and transfers it to water. The difference is that instead of heating water for radiators, it heats pool water directly.
Pool water is pumped from the pool, through the heat pump's heat exchanger, and back to the pool in a continuous loop. The heat pump raises the water temperature by a few degrees each pass. Over several hours, the entire pool reaches the target temperature — typically 26-30°C.
Dedicated Pool Heat Pump vs Home ASHP
There are two approaches, and the right choice depends on your situation.
| Feature | Dedicated Pool Unit | Home ASHP (Dual Use) |
|---|---|---|
| Corrosion resistance | Titanium heat exchanger | Requires plate heat exchanger |
| Installation complexity | Simple — plugs into filtration | Complex — secondary circuit needed |
| Home heating capacity | Unaffected | Reduced |
| BUS grant eligible | No (pool heating) | Home heating only |
| Typical cost | £2,000–£4,500 installed | Additional plumbing £1,000–£2,500 |
For most pool owners, a dedicated pool heat pump is the simpler and more practical choice.
How to Size a Pool Heat Pump
Pool heat pump sizing depends on pool volume, temperature rise needed, and heat loss:
| Pool Size | Volume | Recommended Heat Pump |
|---|---|---|
| Small pool | Up to 30m³ | 8–12kW |
| Medium pool | 30–50m³ | 12–18kW |
| Large pool | 50–80m³ | 18–25kW |
| Indoor pool | Any | Typically smaller (lower losses) |
These assume an outdoor pool with a cover when not swimming. Without a cover, you may need 30-50% more capacity.
A pool cover is the single most effective thing you can do to reduce heating costs — it cuts evaporation (the biggest heat loss factor, up to 70%) dramatically.
Pool Heat Pump Costs
Pool Heat Pump Installed Costs
Budget (8-12kW)
£1,500–£2,300
unit + installation
Mid-range (12-18kW)
£2,300–£4,000
unit + installation
Premium (18-25kW)
£4,000–£6,000
unit + installation
Installation costs are lower than home heating systems — the unit connects directly to existing pool filtration.
Running Costs: Heat Pump vs Gas vs Electric
This is where pool heat pumps really shine:
Generating your own electricity with solar panels can cut pool heating costs even further — especially since pool heating demand peaks in the sunniest months when solar generation is highest.
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Can You Heat a Pool Year-Round?
Yes, but it gets expensive outdoors. An outdoor pool in the UK loses heat rapidly in winter — you might spend £200-£400 per month in the coldest months.
Indoor pools are different. With lower heat losses, an indoor pool can be heated year-round at £50-£120 per month depending on size and insulation.
If you want year-round outdoor swimming, a pool enclosure or retractable cover is a better investment than a larger heat pump — it dramatically reduces heat loss.
Installation Considerations
Positioning
Place the pool heat pump as close to the pool plant room or filtration equipment as practical. The unit needs good airflow — at least 300mm clearance on all sides.
Noise
Pool heat pumps run fans at higher speeds than home heating units. Noise levels are typically 45-55 dB at one metre. Position the unit away from neighbours' boundaries and outdoor seating areas.
Electrical Supply
Most domestic pool heat pumps run on single-phase. Larger units (above 18kW) may require three-phase supply. Check before purchasing.
Pool Cover
A good thermal cover costs £500-£2,000 depending on pool size and type. It pays for itself within one season through reduced heating costs. This cannot be overstated.
Planning Permission
A dedicated pool heat pump is generally treated the same as a home air source heat pump for planning purposes — permitted development in most cases, provided noise limits and boundary distances are respected. In conservation areas or for listed buildings, you may need permission.
For more on how heat pumps work and the installation process generally, see our full installation guide. If you are considering replacing your boiler at the same time, our heat pump vs gas boiler comparison covers the economics.
Thinking about a heat pump for your home as well as your pool?
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Get my free home heating quotes →Pool heating is separate, but a home heating heat pump qualifies for the grant.
Frequently Asked Questions
Can my home heat pump heat my swimming pool?
Some home air-to-water heat pumps can be configured to heat a pool via a secondary circuit and plate heat exchanger. However, this reduces the capacity available for home heating and adds complexity. For most pool owners, a separate dedicated pool heat pump is simpler and more practical.
How long does a pool heat pump take to heat the pool?
From cold (10-15°C) to swimming temperature (28°C), a correctly sized pool heat pump typically takes 24-72 hours for an average domestic pool. Once at temperature, maintaining it requires much less energy — especially with a pool cover.
Is a pool heat pump eligible for the BUS grant?
No. The Boiler Upgrade Scheme grant is for home heating systems only. Dedicated pool heat pumps do not qualify. If your home ASHP also heats the pool, the grant applies to the home heating function only.
How much does it cost to heat a pool per month?
With an air source heat pump and a pool cover, expect £60-£120 per month during the swimming season (April-September) for a typical domestic outdoor pool. Without a cover, costs can double or triple.
Do pool heat pumps work in cold weather?
Yes, but their efficiency drops. Most pool heat pumps work down to 5-10°C ambient. Some models rated for lower temperatures can operate down to -5°C or below, but running costs increase significantly.
How long does a pool heat pump last?
A quality pool heat pump typically lasts 10-15 years with proper maintenance. The main vulnerability is the heat exchanger, which must resist corrosion from chlorinated pool water. Titanium heat exchangers last longest.
About Heat Pump Pool Heating and Home Energy Systems
Air source heat pumps are the most efficient method for swimming pool heating in the UK, achieving COPs of 5.0 or higher during the swimming season. While dedicated pool heat pumps do not qualify for the Boiler Upgrade Scheme, home heating heat pumps can claim £7,500 from the BUS grant. Pairing pool and home heating with solar panels is particularly effective since peak solar generation and pool heating demand coincide in summer. This guide is part of our resource hub covering costs, running costs, and installation for UK homeowners.