Is a dishwasher or washing by hand cheaper? We do the sums

When faced with a pile of dirty dishes, most of us would opt for convenience and choose a dishwasher over washing up by hand. However, with high energy costs and 60% of households in England and Wales on a ‘pay-for-what-you-use’ water meter (Consumer Council for Water), we’re all getting wise to cutting back where we can.

We've investigated using a dishwasher vs washing up by hand, we've done the sums and worked out which is the cheapest when all the costs are taken into account.

How many of us have the option to choose between using a dishwasher and washing up by hand? According to Trend-Monitor, a research organisation that focuses on the home improvement industry, 49% of UK households have a dishwasher. That figure reduces to 29% for single-person households and increases to 56% for households with children, leaving 51% of households washing up by hand.

Those without a dishwasher cited space as a limiting factor or that they wouldn’t use one.

Which uses the most water?

The amount of water you use depends on how you wash up and which programme you select on your dishwasher. If you fill the whole sink with soapy suds and keep the tap running while you wash, you’ll use far more water than if your were to half-fill a washing-up bowl and turn off the tap. Similarly, if you run the dishwasher when it's only half full, your dishes will use more water than if you wait until it's full.

What does the science say?

Research by Bonn University in Germany discovered that the most energy-efficient dishwashers with 12 place settings consumed 15 litres of water. The human testers (113 people from around Europe) used 103 litres of water on average for the same dishes. However, there was a lot of variation, with the  most common amount being 40-50 litres and the most economical using 20-30 litres - still more than the dishwashers.

Similarly, Which? research shows that a nine-litre washing-up bowl has the capacity to wash two place settings at most. So the equivalent of washing 12 place settings would be 9 x 6 = a minimum of 54 litres of water. Which? says that even less-efficient dishwashers show a clear water saving.

Water consumption - dishwasher vs washing by hand

We break down the figures, assuming that we wash up or use the dishwasher five times each week, and each wash would cover 12 place settings.

A place setting is the equivalent of a large dinner plate, a small snack plate, a saucer, a bowl, a coffee cup, a drinking glass, a knife, two teaspoons, a dinner fork and a small salad fork.

Washing by hand

• Uses 54 litres* x 5 (weekly) = 270 litres of water
• This equates to 270 litres x 52 (weeks) = 14,040 litres per year (14.04 cubic metres)
• Water meter bills are charged in cubic metres, at an average of 1.819 per cubic metres**
• Total water cost of washing by hand = 14.04 cubic metres x £1.819 = £25.53 per year

Dishwasher

• Uses 15 litres* x 5 (weekly) = 75 litres of water
• This equates to 75 litres x 52 (weeks) = 3,900 litres per year (3.9 cubic metres)
• Total water cost of dishwashing = 3.9 cubic metres x £1.6142** = £6.30

* Weekly water usage figures taken from research by Which? and the University of Bonn

** Water costs based on Severn Trent scheme of charges for 2022/2023 at £1.6142 per m3

Which uses more energy?

Washing by hand uses far more

The cost of running your dishwasher will depend largely on the energy efficiency of your appliance. The higher the energy efficiency rating, the cheaper it will be to run and the less water it will consume.

All energy rating labels are based on the performance of an appliance’s ‘eco’ setting, so expect to consume more energy if you choose a different programme. Hide says: “By swapping your normal 60-70°C cycle to the eco setting, you save 30% in electricity and water each time you hit the eco button.”

The energy labels on appliances changed in 2021 from A+++ to G to a simpler A to G rating. The change has made it easier to compare products. If you’re in the market for a new dishwasher and want to know more about the energy rating label, AMDEA has a guide.

How to calculate how much energy your dishwasher uses per cycle

• Check on your dishwasher’s energy rating label to find the kWh (kiloWatt hours) of your appliance.
• Multiply the kWh by the cost of your electricity per kWh. You will find this figure on your last energy bill.

Under the current Energy Price Guarantee, most of us are paying 24.50p per kWh for electricity.

Energy consumption – dishwasher vs washing by hand

Washing by hand

• The average washing up session will use a minimum of 54 litres, according to Which?
• Using Omnicalculator, the energy needed to heat 1 litre of water* is equal to 0.06kWh.
• This is a minimum energy usage of 3.24kWh (54 litres x 0.06kWh). That equates to at least £0.80 per washing-up session (3.34kWh x £0.24).
• That could be anywhere north of £208 a year, based on five washing up sessions a week.
• Which? estimates that one bowl of water costs around £0.15 to heat a nine-litre washing up bowl, using a 3kW immersion heater.
• Based on this calculation, washing up would cost £234 a year, based on 12 place settings being washed five days a week, 52 weeks a year.

Dishwasher

• John Lewis' best-selling integrated dishwasher, the E-rated Beko DIN15X20, uses 0.937kWh of energy per eco cycle.
• That is a cost of 0.937kWh x £0.24 = £0.22 per cycle.
• If the dishwasher is run five times a week, 52 weeks a year, its annual cost to run is: 5 x 52 x £0.24 = £57.20 per year.
• If you were to buy an A-rated appliance, such as the Miele G7460, it works out cheaper.
• It would cost 0.29kWh x £0.24 = £0.07 per cycle.
• If the dishwasher is run five times a week, 52 weeks a year, its annual cost to run is: 5 x 52 x £0.07 = £18.20 per year.

*Assuming we heat water from 10 degrees C to 60 degrees C

How much does a dishwasher cost to buy?

Although using a dishwasher may appear cheaper than washing up by hand, there is one element that washing by hand doesn’t need; an appliance. And this is where the comparison becomes trickier because of the price of dishwashers varies enormously. The energy and water they consume also vary depending on the machine’s energy rating, with a higher rating being more efficient, and generally more expensive!

While you can certainly buy a dishwasher for around £200 at the cheaper end of the scale you can pay far more with top-end dishwashers retailing for over £1,000. Exceptional spoke to John Lewis, AO and Currys, who all reported Bosch and Beko to be their bestselling dishwasher brands.

The Beko DIN15X20 at £259 is the best-selling integrated dishwasher at John Lewis, while the Bosch Series SMS2ITW08G  at £399 is the top freestanding buy at John Lewis and AO. Curry’s customers favour the integrated wi-fi enabled Bosch Series 2 SMV2ITX18G at £449, and the freestanding Bosch Series 2 SMS2HVW66G, at £429.

If you’re feeling more extravagant and you could try the fully integrated, A-rated Miele G 7460, but expect to pay more than £1,300.

What are the differences in detergent costs?

Washing-up liquid vs dishwasher tablets

According to Statista, a market data specialist, Fairy Liquid was the number one brand of washing-up liquids and detergents in Great Britain in 2021, with 21.2 million people using the brand. Tesco and Persil followed in second and third place with 4.1 million and 3.2 million users, respectively.

Therefore, for our price comparison, we’re taking the brand leaders to work out the costs of detergent for dishwashers and washing by hand.

* Tesco prices, April 5, 2024

Cost of detergent – dishwasher vs washing by hand

Dishwasher detergent

• Fairy Original All in One dishwasher tablets = £8.00* for 38
• 1 wash = £0.21
• This is an annual cost of £0.21 x 5 x 52 = £54.60

Hand-wash detergent

• Fairy Original Washing up liquid = £2.00* for 654ml
• Fairy recommends using 20ml for every 50 litres of water
• 1 wash = £0.06
• This is an annual cost of £0.06 x 5 x 52 = £15.60

Tesco prices, March 17, 2023

The final verdict

The costs and other benefits, weighed up...

Overall, dishwashers come out on top costs wise vs washing by hand, but figures below are based on several assumptions – including how much water you use when washing up, what dishwasher you buy and how long it lasts.

A dishwasher wins every time if you’re after convenience and have space in your kitchen.

However, dishwashers fall short in terms of the cost of detergent compared to washing up by hand. While water and energy savings are easy to compare, it’s difficult to factor in the cost of an appliance as prices vary widely. If you opt for a very expensive appliance or yours breaks down or needs repairs after a few years, the savings could shrink.

With washing by hand, you can rely on yourself to keep doing the job without needing too many repairs – or a replacement!

But the numbers don't lie – on the face of it and despite extra expenses, all but the most expensive dishwashers are cheaper to use than washing by hand - and could save you almost £100 a year.