How Much Does It Cost to Run a Hot Tub?

A hot tub's heater doesn't run all the time. Once the water is up to temperature, it switches on only to replace the heat that escapes. For a typical tub, that averages about 5% of the time over 24 hours, or a little over an hour a day at 5,500 W: about 6.6 kWh.

That works out at about $1.20 a day in the US, £1.74 in the UK and €2.39 in Germany, or about $36.44, £52.81 and €72.59 a month. Spread across the whole day, the average is about 0.28 kWh an hour, or $0.05 in the US, £0.07 in the UK, €0.10 in Germany, €0.07 in France, and €0.09 in Italy per hour.

These are averages. A well-insulated tub in a mild climate may use much less, while an older tub with a worn cover in a cold, windy place can use two or three times as much.

Most of the energy keeps the water at about 37–40°C (99–104°F) while the air around it is colder. Heat escapes through the cover, the shell and the cabinet, and through evaporation whenever the cover is off. The colder and windier it is, the faster the tub loses heat.

Filling the tub is a cost too. Heating a typical 1,500-litre tub from cold tap water takes roughly 50 kWh, so draining and refilling often adds noticeably to the bill. Circulation and filtration pumps add a smaller, steady amount, and jet pumps use more only while they run.

Inflatable hot tubs usually have smaller heaters, often about 1,500–2,200 W, and much less insulation than hard-shell tubs. In warm weather they can be cheap to run, but in cold weather they lose heat quickly, the heater may run for much of the day, and they can struggle to stay at temperature.

Hard-shell tubs with full-foam insulation and a thick, well-fitting cover usually hold heat best. Small plug-in tubs on a 120 V or 230 V household outlet have smaller heaters and heat up more slowly, but still need to replace the same heat losses.

Ranges are typical for tubs on sale in 2026. The heater's rating is on the tub's spec label or in the manual; real daily use depends far more on insulation, cover and climate than on heater size.

• Keep the cover on whenever the tub isn't in use, and replace it if it's waterlogged, cracked or no longer seals.
• Add a floating thermal blanket under the cover to reduce evaporation and heat loss.
• Shelter the tub from wind with a fence, screen or plants.
• Lower the temperature by a few degrees, or use an economy mode, when you won't use the tub for several days.
• Keep filters clean so pumps don't work harder or run longer than they need to.
• On a time-of-use tariff, set heating and filtration cycles to run in off-peak hours.

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