Wash at 30°C Calculator
See what switching your washing machine from 40°C to 30°C really saves a year — and what dropping one wash a week on top of that could add.
Estimate only. Estimates based on the cycle count, machine energy use and electricity rate you enter — your machine's actual energy label and your supplier's tariff may vary. Source: Energy Saving Trust.
Based on 4 cycles a week, no other changes.
Compare the scenarios
| Scenario | Annual cost | Saving vs 40°C |
|---|---|---|
| Wash everything at 40°C | £48.41 | — |
| Wash everything at 30°C | £29.05 | £19.36 |
| Wash at 30°C + 1 fewer cycle/week | £21.79 | £26.63 |
Also drop one wash a week
Combining loads so you run one fewer 30°C cycle a week saves a further £7.26 a year.
Combined total saving
Switch to 30°C and run one fewer cycle a week and your annual laundry electricity cost drops from £48.41 to £21.79.
Getting more from every wash
- Modern detergents are made to work at 30°C — you lose little to no cleaning power switching down from 40°C for everyday loads.
- Only run full loads. A half-empty machine uses almost the same energy and water as a full one, so combining loads is free money.
- Skip the pre-wash setting unless something is genuinely heavily soiled — it roughly doubles the cycle's energy and water use.
- Eco mode usually runs longer, not hotter — it uses less energy overall by heating more slowly and spinning more efficiently, even though the cycle takes longer.
Why washing at 30°C saves so much
Most of a washing machine's energy use goes on heating the water, not on the motor or spin cycle — so turning the temperature dial down is the single biggest lever you have. Energy Saving Trust estimates washing at 30°C uses around 40% less energy than washing the same load at 40°C, with no meaningful difference in cleaning performance for normal, everyday laundry thanks to modern low-temperature detergents. Combine that with only ever running full loads — cutting out one wash a week by batching loads together — and the two savings stack, since the dropped cycle is also washed at the cooler, cheaper temperature.