An average 8-minute shower using a standard mixer shower uses around 62 kWh of energy per year, whereas a typical bath uses approximately 115 kWh per year, making a shower roughly 46% more energy-efficient according to the Energy Saving Trust (Energy Saving Trust, 2026).
The key variable is water volume. A standard bath holds about 80 litres of hot water, while an 8-minute shower with a mixer shower uses roughly 60 litres. However, power showers can use more than 100 litres in 10 minutes, making them less efficient than a shallow bath. The energy figure assumes heating with a gas boiler at current UK efficiency rates, electric showers are more expensive per kWh but often use less water.
Shower efficiency depends on flow rate and duration
The Energy Saving Trust states that a typical mixer shower with a flow rate of 10 litres per minute uses 60 litres over 8 minutes (Energy Saving Trust, 2026). This translates to around 3.2 kWh per shower when heated from cold to 40°C. In contrast, a power shower with a 15 litres per minute flow rate uses 90 litres over 6 minutes, consuming about 4.8 kWh. Reducing shower time to 4 minutes can halve energy use, while a flow restrictor (costing under £10) can cut water use by 30% without noticeable pressure loss.
Baths use more water but offer less control
A standard bath uses 80 litres of hot water, requiring roughly 4.3 kWh to heat, according to the Energy Saving Trust (Energy Saving Trust, 2026). Filling a bath only halfway reduces this to around 2.2 kWh, but most households fill to a comfortable level. Gas-heated baths cost about 25p per use, while electric immersion heaters cost around 50p. The lack of a timer means baths are less flexible than showers for saving energy.
Combination heating systems change the comparison
If you have a combi boiler, a shower is generally more efficient because it heats only the water you use, unlike a bath that may require reheating a stored tank. The Energy Saving Trust notes that combi boilers reduce standing heat losses by up to 30% compared to a hot water cylinder (Energy Saving Trust, 2026). For electric showers, the cost per kWh is higher (around 28p compared to 6p for gas), but the shorter duration and lower water volume still make them cheaper than a bath in most cases. A family of four switching from baths to short showers could save over £200 annually on energy bills.
A worked example
A typical UK household with two people each taking one 8-minute shower per day using a standard mixer shower will spend roughly £85 per year on energy for showers alone. Compare this to a family of four using a bath each day, which costs about £260 annually. For a 1930s semi-detached house in Manchester, switching from daily baths to 8-minute mixer showers saves £175 per year on gas bills. The upfront cost to install a water-efficient shower head with a flow restrictor is under £20. With 0% VAT on energy-saving materials until March 2027 and potential ECO4 eligibility for low-income households, the payback is immediate. The Energy Saving Trust confirms a standard bath uses 115 kWh per year compared to 62 kWh for a shower, making the switch a straightforward way to cut household energy use without major renovation.
| Item | Figure |
|---|---|
| Upfront cost after grants | £20 |
| Yearly savings | £175 |
| Payback period | Less than 1 year |
| 25-year lifetime savings | £4,375 |
What homeowners often get wrong
The most common mistake is assuming all showers are more efficient than baths, which is not true for power showers. Here are three frequent errors homeowners make when comparing shower vs bath energy use.
- Thinking a longer shower always saves energy A 15-minute power shower uses over 100 litres of hot water, which is more than a shallow bath at 80 litres. The right answer is that a power shower can cost 30% more per use than a bath, wasting up to £50 per year for a two-person household.
- Ignoring the flow rate of their shower Many homeowners assume a standard mixer shower uses 10 litres per minute, but older models can run at 15 litres per minute. The right answer is to check the flow rate with a bucket and stopwatch, a 30% reduction from a £10 flow restrictor can cut annual shower energy costs by £25, a saving often missed without measurement.
- Believing electric showers are cheaper to run Electric showers are often perceived as cheaper because they heat water instantly, but electricity costs roughly 4 times more per kWh than gas. The right answer is that a 5-minute electric shower costs about 30p, while a gas-heated mixer shower costs around 15p, so electric showers can be twice as expensive per minute despite using less water.
Quick reference
- A standard 8-minute mixer shower uses 62 kWh per year, while a typical bath uses 115 kWh per year according to the Energy Saving Trust.
- Power showers with a flow rate above 12 litres per minute can use over 100 litres in 10 minutes, making them less efficient than a shallow bath.
- ECO4 grants can fully fund a new efficient shower head and flow restrictor for eligible low-income households in the UK.
- Reducing shower time from 8 minutes to 4 minutes halves energy use, saving a typical household £42 per year on gas bills.
- Installing a flow restrictor costing under £10 can cut water use by 30% without reducing pressure, a simple upgrade often overlooked.
Frequently Asked Questions
A standard mixer shower uses about 0.4 kWh per minute when heating water from cold to 40°C. The Energy Saving Trust confirms this figure based on a 10 litres per minute flow rate.
A shower is cheaper if kept under 8 minutes, using roughly 3.2 kWh versus a bath's 4.3 kWh. The Energy Saving Trust advises that power showers over 10 minutes can cost more than a shallow bath.
Reduce shower time to 4 minutes to halve energy use, or install a flow restrictor for under £10 to cut water use by 30%. Ofgem recommends these measures for energy efficiency.
