Dishwasher energy use: the baseline
A dishwasher's energy consumption varies by model, programme, and load. The standard figures used across UK consumer guides and Ofgem calculations are:
- Standard programme: 1.5kWh per cycle
- Eco programme: 1.1kWh per cycle
These figures assume a full load on a modern A-rated dishwasher. Older machines (pre-2018) often use 1.8 to 2.0kWh per cycle. Very efficient modern models can get as low as 0.7kWh on a rated eco cycle, though this is the exception rather than the norm.
The EU energy label rates dishwashers from A (most efficient) to G. The majority of machines on sale in 2026 sit between C and F on the new scale. Look for D or better when buying new. The annual energy saving between an F-rated and a D-rated machine is typically 15 to 30kWh per year, worth £4 to £8 at price cap rates, or around £1 at overnight Agile rates.
Annual cost at each tariff scenario
The table below shows the full annual running cost for daily use (365 cycles per year) across every relevant pricing scenario for 2026. Standard and eco modes are shown separately.
| Tariff scenario | Rate (p/kWh) | Standard mode (1.5kWh) - per cycle | Standard mode - annual | Eco mode (1.1kWh) - per cycle | Eco mode - annual |
|---|---|---|---|---|---|
| Price cap (July 2026) | 26.11p | 39p | £143 | 29p | £105 |
| Agile peak (evening) | 38p | 57p | £208 | 42p | £153 |
| Agile average daytime | 20p | 30p | £110 | 22p | £80 |
| Agile overnight | 4p | 6p | £22 | 4p | £16 |
| Plunge pricing | 0p or negative | 0p | Near £0 | 0p | Near £0 |
The difference between the worst case (£208/year at Agile peak, standard mode) and the best case (£16/year at overnight Agile, eco mode) is £192 per year. That is four months of Netflix. A winter weekend away. Multiple restaurant meals. It comes from two changes: pressing delay start, and selecting eco mode.
Check the live Agile price dashboard each evening to confirm tonight's overnight window before setting your delay start. The overnight trough is not always at midnight; it shifts based on wind generation and demand. Targeting the actual lowest 2-hour window adds another £5 to £15 per year on top of simply running overnight.
The overnight timing saving: the numbers
The core saving available to every Octopus Agile customer with a dishwasher is the overnight shift. No new appliance required. No eco mode needed (though it helps). Just setting delay start before bed.
If you currently run your dishwasher in the evening at peak rates, here is what switching to overnight saves:
- From peak (38p) to overnight (4p): save £186/year (standard mode, daily)
- From price cap (26.11p) to overnight (4p): save £121/year (standard mode, daily)
- From price cap to overnight eco mode: save £127/year (daily)
The peak-to-overnight ratio on Agile is typically 8 to 20 times. The ratio is most extreme during cold winter evenings when heating demand peaks and grid stress pushes Agile prices highest. These are also the nights when overnight rates are cheapest relative to evening rates, because wind generation often picks up overnight. The saving is largest exactly when grid conditions are most extreme.
For a full walkthrough of how to target the cheapest overnight window each night, read the complete dishwasher timing guide.
Eco mode impact on annual cost
Eco mode reduces energy use from 1.5kWh to 1.1kWh per cycle, a 27% reduction. Applied to daily use over a full year, the savings are:
- At price cap: saves £38/year (from £143 to £105)
- At Agile overnight 4p: saves £6/year (from £22 to £16)
- At Agile peak: saves £55/year (from £208 to £153)
The eco mode saving is proportionally constant (27%) regardless of the tariff. In absolute terms, the saving is largest at peak rates, but those should already be avoided by switching to overnight timing. The marginal gain from eco mode on top of overnight Agile timing is modest at £6/year, but it is free and adds up.
The main reason to use eco mode on Agile is not the financial saving alone. Eco mode also uses less water (9 litres versus 10 to 12 litres for standard). Combined with running only full loads, eco mode represents the most resource-efficient way to use a dishwasher. Read the detailed eco mode guide for the cleaning quality comparison.
Best eco dishwashers UK 2026 by running cost
If you are in the market for a new dishwasher, here are the models that stand out for running cost efficiency in 2026. All figures assume daily use on eco mode at overnight Agile 4p/kWh.
| Model | Energy rating | Eco mode (kWh) | Annual cost (overnight Agile) | Approx price |
|---|---|---|---|---|
| Bosch Series 6 SMS6ZCI48E | A | 0.83 kWh | £12/year | £550-650 |
| Miele G5432SC | A | 0.77 kWh | £11/year | £700-850 |
| AEG FFB53937ZW | B | 0.93 kWh | £14/year | £450-550 |
| Hotpoint H7F HP33 UK | C | 1.05 kWh | £15/year | £280-350 |
| Beko BDEN38522DX | D | 1.10 kWh | £16/year | £200-280 |
Note: energy consumption figures from manufacturer specifications. Real-world figures may vary by 10 to 20%. All models include delay start. Prices are indicative based on June 2026 market data.
At overnight Agile rates, the difference in annual running cost between the most efficient (£11/year) and least efficient (£16/year) models in this table is just £5. This means the efficiency premium of top-end machines is difficult to justify on running cost alone for Agile users. For standard tariff customers, the premium is more significant: the difference between A and D rated machines is around £27/year at price cap rates.
Total cost of ownership: buying vs running
A budget dishwasher costs £200 to £300. A premium efficient model costs £600 to £900. The difference in annual running cost at overnight Agile is roughly £4 to £5 per year. At that rate, the premium machine pays back its additional purchase cost in 80 to 140 years on electricity savings alone.
This does not make budget machines wrong. It makes the running cost argument for premium dishwashers irrelevant for Agile users. Buy for features, reliability, build quality, and noise level. Running cost differences between well-maintained modern machines are negligible once overnight Agile timing is in place.
The most impactful decision is not which dishwasher you buy: it is what time it runs. A D-rated dishwasher on overnight Agile costs the same annually as an A-rated machine running at peak evening rates costs per month.