- The Consumer Council for Water: “A full bath uses 80 litres.” A power or mixer shower uses around 15 litres a minute and an electric shower 6.1
- So a power or mixer shower uses as much water as a bath in about 5.3 minutes; an electric shower in about 13.3 minutes.
- Heating the water, in the government's SAP model with January mains water: a bath 25p with gas, a 6-minute shower 17.9p, an electric shower 24.5p.3
- Last checked: 28 October 2026.
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Water used
NI Water: “In 5 minutes a standard shower uses 35 litres and a power shower uses 90 litres of water.” and “Watch out for power-showers though, they use as much water as a bath!”2
Energy to heat the water
The government's SAP 10.2 method works out hot water energy as litres x temperature rise x 4.18 / 3600 (kWh). It assumes a bath of 73 litres at 42°C and “an assumed 6 minutes shower duration” at 41°C, and mains water at 8.0°C in January (18.4°C in July).3
| Energy | Gas boiler at 92% | Electric (immersion or shower) | |
|---|---|---|---|
| Bath, 73 litres at 42°C | 2.88 kWh | 25p | 75.9p |
| Shower, 6 minutes at 9 litres a minute | 2.07 kWh | 17.9p | 54.5p |
| Electric shower, 9.3 kW for 6 minutes | 0.93 kWh | n/a | 24.5p |
Gas costs assume a boiler meeting Approved Document L's 92% minimum for systems fitted now; heat lost from pipes and hot water cylinders is not included.4
The cost of the water itself is not included.
Who these figures cover
Costs use the Ofgem price cap average for England, Scotland and Wales, 26.32p per kWh by Direct Debit, 1 October to 31 December 2026. Your region and tariff change it.5
HMRC: “The temporary zero rate applies from 1 October 2026 to 30 June 2027.” The Budget on 28 October 2026 extended it from 31 March (announced; the legislation is due in early 2027). Gas stays at 5% VAT.6 In Northern Ireland, use the unit rate on your bill.