Appliances
What a dishwasher costs per run at night vs in the day (UK)
Last checked: 15 October 2026 · SmartShift UK
The homepage timer-shift calculator uses 1.1 kWh per dishwasher run. Real programmes vary a lot (eco cycles use less, intensive cycles more), so check the kWh figure on your machine’s energy label or manual and swap it into the sums below.
| Appliance (calculator figure) | kWh per run | At 7.6p (night) | At 26.32p (cap) | Saved per run |
|---|---|---|---|---|
| Dishwasher | 1.1 | 8.4p | 29.0p | 20.6p |
| Washing machine | 0.9 | 6.8p | 23.7p | 16.8p |
A year of dishwasher runs
- Five runs a week is 260 runs a year.
- Moving each run from 26.32p to 7.6p saves 1.1 × 18.72p = 20.59p.
- 260 × 20.59p = £53.54 a year.
- On Intelligent Octopus Go itself the day rate is a regional quote, 34.95p to 38.82p on the fixed version on sale on 15 October 2026, not 26.32p. Against that, a run moved into the night saves 30.1p to 34.3p.
The saving only exists on a time-of-use tariff with a cheap night rate. On a single-rate tariff a run costs the same at any hour. Rates for the main EV and off-peak tariffs are in UK EV tariffs compared.
Using Delay End
Many dishwashers and washing machines have a delay timer. A “Delay End” or “finish by” setting is the easiest to use: set it so the programme ends at 05:00, and it starts itself inside the 23:30–05:30 window. A “Delay Start” timer needs you to count back from the programme length instead. Most of a dishwasher’s electricity goes on heating water, so the start of the programme should be well inside the window.
Safety first
London Fire Brigade’s bedtime advice is not to leave the washing machine, tumble dryer or dishwasher on overnight and unattended. If you do run them on a timer, have working smoke alarms, keep the machine’s filter clean, and never run anything that has a known fault or recall. A safer pattern is to start it at 23:30 before you go to bed, or set it to finish as you get up.
Washing machine version
At the calculator’s 0.9 kWh, a wash costs 6.8p at night and 23.7p at 26.32p, saving 16.8p a run. Five washes a week saves £43.80 a year. The same fire safety advice applies. For drying, see winter laundry drying and heat pump tumble dryers.
Try your own run count and rates in the timer-shift calculator, or schedule older machines with a smart plug where the manufacturer allows it.
Questions people ask
How much does it cost to run a dishwasher at night?
At 1.1 kWh a run, about 8.4p at a 7.6p night rate, against 29.0p at the 26.32p price cap. Check your machine’s own kWh figure on its energy label.
Is it cheaper to run a dishwasher at night in the UK?
Only on a time-of-use tariff with a cheaper night rate, such as an EV tariff or Economy 7. On a single-rate tariff, a run costs the same at any time.
Is it safe to run a dishwasher overnight?
London Fire Brigade advises not to leave a dishwasher, washing machine or tumble dryer running overnight and unattended. If you use a timer, have working smoke alarms and consider starting it before bed or finishing it as you get up.
Is this financial advice?
No. It is arithmetic from published rates and the calculator’s example kWh figures.
Not financial advice. These are worked examples from published rates and EV-Database consumption estimates, for planning only. Your own tariff, day rate, standing charge, car, driving and weather will change the numbers. Check your bill and your supplier’s current terms before you switch or buy anything.
Sources
- London Fire Brigade, bedtime checks
- Octopus Energy, Intelligent Octopus Go (checked 15 October 2026)
- Octopus Energy tariff API, Intelligent Octopus Go 12M Fixed October 2026 v1 (regional day rates)
- Ofgem, energy price cap unit rates and standing charges (1 October–31 December 2026)
- SmartShift UK, UK EV tariffs compared (checked 15 October 2026)
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