Hot tub running cost calculator

How much does your hot tub cost to run? Enter your heater power, hours and tariff for a daily, weekly, monthly and yearly figure at 26.32p/kWh.

By Matthew Smart · Rates correct as of 5 October 2026

How to use it

1Enter your hot tub’s heater power. Check the spec label — 2.0 kW is typical for an inflatable Lay-Z-Spa.
2Set how many hours the heater is actually running each day, and how many days a month you use it.
3Leave the rate at 26.32p/kWh (the Ofgem Energy Price Cap) or change it to your own tariff.
4The duty cycle is the share of that time the heater is genuinely drawing power. Once the water is warm it cycles on and off, so 70% is a realistic default.

Hot tub running cost calculator

The tables in the guides use typical figures. Your hot tub is different — its heater wattage, how long you run it and your tariff all change the real number. Enter your own figures below.

Heater power(kW)

2.0 kW is typical for an inflatable spa. Rigid tubs are often 3.0 kW.

Heating hours per day(hours)

Time the heater is on, not the time the tub sits idle.

Duty cycle(%)

Real heaters cycle on and off once the water is up to temperature. 70% is a sensible default.

Days used per month(days)

Your electricity rate(p/kWh)

Pre-filled with the Ofgem Energy Price Cap unit rate for 1 October – 31 December 2026. Change it to the rate on your own bill.

Your estimate

Per day4.20 kWh a day: £1.11
Per week: £7.74
Per month: £33.16
Per year: £398
Share of typical household electricityAgainst 2,700 kWh a year, Ofgem’s typical domestic figure: 56%

Assumes a 2 kW heater running 3 hours a day at a 70% duty cycle once the water is up to temperature, 30 days a month, at 26.32p per kWh (Ofgem Energy Price Cap, 1 October – 31 December 2026). This estimates heating only — it does not include your pump, water, chemicals or the initial heat-up from cold, which is the most expensive part. Rates correct as of 5 October 2026.

Before you treat the number as gospel

The figure below covers your heater while the water is already warm. It does not include the initial heat-up, which is the most expensive part of hot tub ownership — filling from cold and bringing the water up to temperature can cost several pounds on its own, depending on capacity. It also excludes your pump, water and chemicals. I cover the initial heat-up, and how to bring it down, in the full breakdown.

Rates correct as of 5 October 2026. Updated each time the price cap changes.

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