The short answer
Heating is the biggest running cost of a pool, and the system you choose makes a large difference. An air-source heat pump is usually the lowest-priced to run because it moves heat rather than burning fuel — roughly £200–£500 per season for an outdoor pool, often around £5 per day at swimming temperature. Gas heating is much higher at around £800–£3,000 per season depending on use and gas price. Direct electric is the most expensive per unit of heat. Solar heating has very low running cost once installed but works best as a top-up in sunnier months. These figures assume a 2026 electricity price of about 27.7p per kWh; a pool cover, which cuts evaporation, lowers all of them.
Almost all the cost of keeping a pool warm comes down to the heat source and how much heat the pool loses. The figures below assume a 2026 electricity price of about 27.7p per kWh, and are seasonal for a typical outdoor family pool.
Typical heating cost
- Heat pump~£200–£500 / season
- Gas heater~£800–£3,000 / season
- Direct electrichighest cost per unit
- Solarvery low to run; sunny-month top-up
- Electricity assumed~27.7p / kWh (2026)
How the heating options compare
An air-source heat pump works out lower in cost than the alternatives for most outdoor pools, because it draws heat from the air and delivers several units of heat for each unit of electricity, rather than generating it directly — roughly £200–£500 over a season. Gas heats quickly but costs far more to run, often £800–£3,000 a season depending on gas price and how warm you keep the water. Direct electric heaters are simple and cheap to buy but the most expensive to run per unit of heat. Solar panels or mats have almost no running cost once fitted, but in the UK they work best as a warm-month top-up rather than a sole heat source.
| Heating system | Typical running cost | Best for |
|---|---|---|
| Air-source heat pump | ~£200–£500 / season | lowest running cost, main heat source |
| Gas heater | ~£800–£3,000 / season | fast heat, occasional use |
| Direct electric | highest per unit | small or back-up use |
| Solar | very low once installed | sunny-month top-up |
Indicative UK figures for guidance, assuming ~27.7p/kWh electricity (2026). Sources: Compass Pools and 1st Direct Pools heating guides.
How to lower the heating bill
The lowest-cost heat is the heat you don't lose. A pool cover is the most effective single saver because it cuts evaporation, which is where most heat escapes; fitting one can meaningfully reduce whichever heater you use. Beyond that, an air-source heat pump typically works out lower in cost than gas or direct electric; heating to a sensible temperature rather than bath-warm saves energy on every swim; and for outdoor pools, heating only through the season rather than year-round keeps the seasonal figure down. Solar can sensibly supplement a heat pump in summer.
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Frequently asked questions
What is the lowest-cost way to heat a swimming pool?
For most UK outdoor pools an air-source heat pump works out lower in cost to run — roughly £200–£500 per season — because it moves heat rather than generating it. Pairing it with a pool cover, which cuts evaporation, lowers the cost further.
How much does gas pool heating cost?
Gas heating is typically around £800–£3,000 per season depending on how warm you keep the water, how often you swim and the gas price. It heats quickly but costs considerably more to run than a heat pump.
Does solar heating work for a UK pool?
Solar has very low running cost once installed and is a sensible warm-month top-up, but UK sunshine means it usually works best alongside a heat pump rather than as the only heat source.
Sources & further reading
- Compass Pools — choosing a heating system for your pool
- 1st Direct Pools — swimming pool heat pump costs and options
Figures on this page are typical UK ranges drawn from published sources and depend on your specific property. They are guidance, not a quotation.