At the Ofgem cap rate for 1 July to 30 September 2026, a dishwasher rated 1800W costs about 47.0p a use and £120.08 a year when 2.5 hours a time, 5 times a week.
| Per hour of running | 18.8p |
|---|---|
| Per use | 47.0p |
| Per day | 32.9p |
| Per year | £120.08 (460 kWh) |
Calculated at 26.11p per kWh, the capped electricity unit rate for 1 July to 30 September 2026 on a standard variable tariff paid by direct debit, including VAT. The 57.19p daily standing charge is not included, because you pay that whether or not anything is switched on.
Two things worth knowing about that figure. The cap limits the unit rate, not your bill, so using more still costs more. And it is a Great Britain average: the actual capped rate is set per region, running from roughly 25.1p in the East Midlands to 27.7p in North Wales and Mersey, so your own rate could move these numbers by around a tenth either way. It is on your bill.
Dishwasher has a thermostat, so the element or compressor switches off once it reaches temperature and back on when it drifts. The figures above assume it draws full power roughly 40% of the time it is on, which is typical.
This is where most running-cost figures online go wrong. Multiplying 1800W by the hours it is switched on would give £300.20 a year, which is roughly 2.5 times the real figure.
Figures for dishwasher run from about 1200W to 2400W. As with a washing machine, the heating element does the work: heating the water and then heating the air to dry. Eco programmes run longer at a lower temperature and use less total energy than the intensive cycle.
Use the eco programme, run it full, and skip the heated dry by opening the door at the end to let the dishes air dry. Scraping rather than pre rinsing under a hot tap saves more than the cycle choice does.
Pre rinsing everything under hot running water, which can use more hot water than the machine does.
Annual running cost against the appliances closest to it, on the same assumptions. The ordering surprises people: short bursts of very high wattage usually cost less than something modest left on for hours.
| Appliance | Per year |
|---|---|
| Desktop PC | £152.48 |
| Tumble dryer | £142.95 |
| Dishwasher | £120.08 |
| Fridge freezer | £102.93 |
| Washing machine | £98.07 |
Across a year, a dishwasher on these assumptions is about 18.4% of a typical annual electricity bill of £652.75 at these rates.
The figures here use the capped rate. If you are on a fixed tariff, or you want to add several appliances together, put your own unit rate into the energy cost calculator on the homepage.