4-person hard-shell hot tub running cost — Winter daily use (1.5 h, tub covered)
Winter daily use with a good insulating cover: higher maintenance fraction (15%) due to cold ambient temperature. A 4-person hard-shell hot tub (3,000 W heater + 1,500 W pump) costs approximately £30.84/week at Ofgem cap 26.11p/kWh (1 July to 30 September 2026).
4-person hard-shell hot tub — Winter daily use (1.5 h, tub covered): Active: 6.75 kWh (1.5 h × 4.5 kW). Standby: 10.13 kWh (22.5 h × 3.0 kW × 15%). Total/day: 16.88 kWh = £4.41. Weekly (7 days): £30.84. Annual: £1603.81. Source: Which? — How much does a hot tub cost to run (electricity consumption data) + Ofgem (OGL v3.0).
- Per day (used)
- £4.41
- Per week (7 days)
- £30.84
- Per month
- £133.65
- Per year
- £1603.81
Tub specification
- Seats
- 4 adults
- Heater
- 3,000 W
- Pump
- 1,500 W
- Active use
- 1.5 h/day
- Standby load
- 15% of heater
- Days used/week
- 7
Hydropool / Caldera typical 4-person hard-shell: 3 kW heater + 1.5 kW pump (Which? 2024)
How the cost is worked out
- Active use: (3,000 W + 1,500 W) ÷ 1000 × 1.5 h = 6.75 kWh.
- Standby: 3,000 W ÷ 1000 × 22.5 h × 15% = 10.13 kWh.
- Daily total: 6.75 + 10.13 = 16.88 kWh × 26.11p = £4.41.
- Weekly: £4.41 × 7 days = £30.84.
- Annual: £30.84 × 52 = £1603.81.
Same scenario — other tub sizes
Track hot tub running costs
Updated each time the Ofgem cap changes.
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Heater and pump specs from Which? — How much does a hot tub cost to run (electricity consumption data). Unit rate 26.11p/kWh from Ofgem — Energy price cap unit rates and standing charges (1 July to 30 September 2026), OGL v3.0.