Dishwasher energy ratings explained: the label, eco mode and cost per wash

Quick answer: The dishwasher label shows energy per 100 eco cycles, not per year. A typical current machine uses about 74 kWh per 100 cycles, which is 19.3p a wash at the 26.11p/kWh cap rate, or roughly £40 a year at four washes a week. The most efficient full-size models get that down to about 14p.

What does the dishwasher energy label show?

Since the 2021 label reset, dishwashers are rated A to G based on their eco programme, and every figure on the label comes from that programme. The Energy Saving Trust lists what you will find: energy use per 100 eco cycles, water use per cycle, the eco cycle’s duration, place-setting capacity and a noise rating.

Here’s a real one. Bosch’s Series 6 SMS6ZDW48G, a current 60cm freestanding model, publishes these figures on its official spec sheet (checked August 2026): energy class C, 74 kWh per 100 eco cycles, 9.5 litres of water per cycle, 13 place settings, and an eco programme that runs 3 hours 55 minutes.

The per-100-cycles format is the useful one, because you can turn it into a cost per wash in one step: divide by 100, multiply by your unit rate. For the Bosch: 0.74 kWh x 26.11p = 19.3p a cycle.

How is the A to G rating worked out?

The letter comes from an Energy Efficiency Index (EEI), which scores the machine’s eco-cycle consumption against a reference machine of the same capacity. The UK regulation sets the boundaries: A needs an EEI under 32, D sits between 44 and 50, and anything over 62 is G.

Because the score is relative to capacity, a 14-place machine isn’t penalised for being bigger than a slimline 10-place one. It also means the gap between letters is real and roughly proportional: a machine at the bottom of class D can use around half as much energy again per cycle as one that just scrapes an A.

What does a cycle actually cost in 2026?

At the July to September 2026 cap rate of 26.11p/kWh, the sums look like this:

Worked example for the middle row: 74 kWh per 100 cycles = 0.74 kWh a cycle. 0.74 x 26.11p = 19.3p. Four washes a week is 208 a year: 208 x 19.3p = £40.19. The most efficient machines on Sust-it’s ranking, such as AEG’s 14-place GI8200X5TN, come out at about 14p a cycle on the same tariff. That £11-a-year difference is real but modest; the bigger jump is from an ageing machine to any current one.

And yes, the machine still beats the sink for most households. We ran those numbers separately in our dishwasher vs washing up comparison.

Is eco mode actually cheaper?

Eco mode looks wrong from the outside: nearly four hours for the Bosch above, against an hour or so for a quick wash. But the duration is the point. The programme heats water to a lower temperature and holds it there, and heating water is where almost all the energy goes.

The long eco cycle is the cheapest programme on the machine, and it’s the one every label figure is based on. Quick and intensive programmes heat faster and hotter, so they cost more per wash even though they finish sooner. Use eco by default, and save the fast programme for when you genuinely need plates back in an hour.

One honest caveat: label figures come from standardised lab conditions with a full load. Half-load your machine and the cost per plate roughly doubles, whatever the programme. Running it full matters more than which brand you buy.

A vs D: what’s the real gap?

Take a household doing 208 cycles a year. An efficient A-class machine at about 14p a cycle costs £29. A machine at the bottom of class D, using around half as much energy again, lands near £44. That’s £15 a year, or around £180 over a 12-year life at today’s rate.

Worth paying for? If the A-rated model costs £100 more, yes, comfortably. If it costs £400 more, the energy saving alone won’t pay you back, and you’re really buying quietness and build quality. Buy on the kWh-per-100-cycles number and the price gap together, not the letter. The same logic applies to washing machine ratings, where the spread within class A is bigger than the A-to-B boundary itself.

FAQs

What is a good kWh figure for a dishwasher?

For a full-size machine, under 65 kWh per 100 cycles is excellent, low 70s is typical of decent current models, and anything over 90 is expensive to run. Slimline machines use less per cycle but wash fewer items, so compare per place setting if you’re torn between sizes.

Does the eco programme clean properly?

Yes, for everyday loads. It compensates for lower temperature with time. Heavily burnt-on pans may still need the intensive programme; that’s fine as an exception rather than a default.

How much does a dishwasher add to your bill per year?

Between about £29 and £60 at the current 26.11p/kWh rate, depending on the machine and how often you run it. If you want to see where that sits against everything else in the kitchen, our appliance running-costs roundup covers the rest of the kitchen, and our guide to standby energy waste covers what it costs when it’s off.