4-person hard-shell hot tub running cost — Standby / maintain temperature only
Tub is kept hot but not used — standby heating cost only. A 4-person hard-shell hot tub (3,000 W heater + 1,500 W pump) costs approximately £13.16/week at Ofgem cap 26.11p/kWh (1 July to 30 September 2026).
4-person hard-shell hot tub — Standby / maintain temperature only: Active: 0.00 kWh (0 h × 4.5 kW). Standby: 7.20 kWh (24.0 h × 3.0 kW × 10%). Total/day: 7.20 kWh = £1.88. Weekly (7 days): £13.16. Annual: £684.29. Source: Which? — How much does a hot tub cost to run (electricity consumption data) + Ofgem (OGL v3.0).
- Per day (used)
- £1.88
- Per week (7 days)
- £13.16
- Per month
- £57.02
- Per year
- £684.29
Tub specification
- Seats
- 4 adults
- Heater
- 3,000 W
- Pump
- 1,500 W
- Active use
- 0 h/day
- Standby load
- 10% 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 × 0 h = 0.00 kWh.
- Standby: 3,000 W ÷ 1000 × 24.0 h × 10% = 7.20 kWh.
- Daily total: 0.00 + 7.20 = 7.20 kWh × 26.11p = £1.88.
- Weekly: £1.88 × 7 days = £13.16.
- Annual: £13.16 × 52 = £684.29.
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.