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Hot Tub · Ofgem 1 July to 30 September 2026

4-person hard-shell hot tub running cost — Summer daily use (1.5 h, warm ambient)

Summer daily use: lower maintenance fraction (5%) because warmer ambient temperature reduces heat loss. A 4-person hard-shell hot tub (3,000 W heater + 1,500 W pump) costs approximately £18.51/week at Ofgem cap 26.11p/kWh (1 July to 30 September 2026).

4-person hard-shell hot tub — Summer daily use (1.5 h, warm ambient): Active: 6.75 kWh (1.5 h × 4.5 kW). Standby: 3.38 kWh (22.5 h × 3.0 kW × 5%). Total/day: 10.13 kWh = £2.64. Weekly (7 days): £18.51. Annual: £962.28. Source: Which? — How much does a hot tub cost to run (electricity consumption data) + Ofgem (OGL v3.0).

Per day (used)
£2.64
Per week (7 days)
£18.51
Per month
£80.19
Per year
£962.28

Tub specification

Seats
4 adults
Heater
3,000 W
Pump
1,500 W
Active use
1.5 h/day
Standby load
5% 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

  1. Active use: (3,000 W + 1,500 W) ÷ 1000 × 1.5 h = 6.75 kWh.
  2. Standby: 3,000 W ÷ 1000 × 22.5 h × 5% = 3.38 kWh.
  3. Daily total: 6.75 + 3.38 = 10.13 kWh × 26.11p = £2.64.
  4. Weekly: £2.64 × 7 days = £18.51.
  5. Annual: £18.51 × 52 = £962.28.

Same scenario — other tub sizes

2-person inflatable hot tub: £6.03/wk4-person inflatable hot tub: £11.31/wk6-person hard-shell hot tub: £34.27/wk

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.