Quick Answer
A full dishwasher on an efficient programme can be a more economical choice than washing dishes under a running hot tap. However, there is no single answer for every household. The result depends on your dishwasher, the programme, how you heat water and whether you pay metered water charges. For a few items, washing up in a bowl may be the more practical option.
After dinner, the decision often comes down to habit. Some people load the dishwasher without thinking twice. Others wash everything by hand because running a machine for plates and cups feels expensive.
Neither approach tells the whole story. A dishwasher uses electricity and water, but handwashing also has a cost when you heat water. Leaving the hot tap running while you rinse every item can change the comparison considerably.
The useful question is how much energy and water you use to clean the same amount of washing up. Here is how to make that comparison without relying on a headline saving that may not apply to your home.
What Affects the Cost of Washing Dishes?
Four things make the biggest difference:
- The amount of washing up.
- The dishwasher programme you choose.
- The quantity of hot water used when washing by hand.
- Your electricity, water and water-heating costs.
Household routines matter too. A family that fills a dishwasher each evening has a different pattern from someone living alone who uses a mug, plate and saucepan.
Before changing your routine, think about what actually happens in your kitchen. Do you run the machine half-empty? Do you wash dishes while the tap stays on? Do items need washing again because they were badly loaded?
Those details can matter more than whether you use a machine or a sink.
When a Dishwasher Can Be the Better Choice
A dishwasher is worth considering when you have enough suitable dishes for a properly loaded cycle.
Energy Saving Trust recommends waiting for full dishwasher loads and using efficient settings. That helps avoid spending energy and water on repeated small loads. Energy Saving Trust
“Full” should still mean loaded correctly. Plates pressed tightly together, bowls covering other items and utensils blocking the spray arms can leave food behind.
If you have to wash several items again, you lose some of the benefit of completing everything in one cycle.
Check your machine’s loading instructions. Leave the spray arms free to turn, place items in their intended positions and avoid squeezing in one last pan if it stops water reaching the rest of the load.
Why the Shortest Programme May Not Be the Cheapest
A quick wash is convenient when you need clean dishes soon. However, a shorter running time does not automatically mean lower electricity consumption.
Check the programme table in your appliance manual. Compare the energy and water figures for the cycles you actually use, rather than judging them by duration alone.
Energy Saving Trust advises using the most efficient water and energy settings available. Energy Saving Trust
An efficient programme may take longer than you expect. If you do not need the dishes immediately, that longer duration may be less important than the consumption figures.
You can read more in its guide to saving energy in the kitchen.
Choose a programme appropriate for the load. Heavily soiled cookware may need different treatment from lightly used glasses, and some materials should not go into the dishwasher at all.
When Washing Up by Hand Makes Sense
Handwashing can be sensible when you only have a few items or need something again before the dishwasher is ready to run.
It is also necessary for cookware and utensils that the manufacturer says are unsuitable for machine washing.
The main thing to watch is how you use hot water. Filling a washing-up bowl gives you more control over the quantity used than leaving the tap running throughout the job.
Energy Saving Trust recommends using a bowl rather than washing under a running tap to reduce water and energy use. Energy Saving Trust
For a small amount of washing up, avoid filling a large sink unnecessarily. Use enough water for the job and follow the cleaning instructions for the items involved.
Keep handwashing separate from the dishwasher comparison when the loads are different. Washing one mug is not the same task as cleaning a full day’s plates, bowls and cutlery.
How to Calculate Your Dishwasher’s Electricity Cost
Find the energy information for your dishwasher. If the label gives consumption in kWh per 100 cycles, divide that number by 100 to find the labelled average per cycle.
Then multiply by your electricity unit rate.
Cost per cycle = kWh per cycle × electricity price per kWh.
For example, suppose a dishwasher’s label shows 80 kWh per 100 cycles:
- 80 ÷ 100 = 0.8 kWh per cycle.
- At an illustrative electricity rate of 25p per kWh, the electricity cost is 20p per cycle.
These are example figures, not a current tariff quote or a typical cost for every dishwasher.
Check which programme the label describes. A different cycle, optional drying setting or repeat wash may change consumption.
This calculation covers electricity only. Add detergent and any applicable metered water and wastewater costs if you want a fuller estimate.
Why Handwashing Costs Are Harder to Compare
With handwashing, water use depends heavily on the person doing it.
One household may wash everything in a bowl and rinse briefly. Another may leave hot water flowing while scrubbing, rinsing and arranging dishes on the draining board.
The method used to heat that water matters as well. Gas-heated hot water and an electric immersion heater have different costs, so applying the electricity rate to every handwashing calculation would be misleading.
If you want a more useful comparison, start by measuring or estimating the water you use for a normal load. Include refilling the bowl and rinsing rather than counting the initial fill alone.
For households without a water meter, reducing water use may not directly change the water bill. Heating less water can still affect energy use.
Should You Rinse Plates Before Loading?
Follow your dishwasher’s instructions rather than assuming every plate needs a full wash under the tap first.
Remove leftover food as recommended, and check how the manufacturer advises preparing the load. Habitually rinsing everything with hot water adds another stage of water heating to the job.
If dishes repeatedly come out dirty, check the loading, programme and maintenance instructions. The answer may be an obstructed spray arm or filter that needs cleaning.
For more on looking after existing appliances, see Stokes’ guide to keeping appliances running longer without overspending.
A machine that is not working properly should be assessed before you assume the problem requires replacement.
Small Changes That Make the Routine More Efficient
You do not need a new appliance to review how you wash dishes.
Start with a few manageable changes:
Wait for a Suitable Load
Avoid running the dishwasher automatically after every meal if it contains only a handful of items. Equally, do not overload it to delay a cycle.
Check Your Programme
Look at the consumption figures in the manual and choose an appropriate efficient setting when it suits the load.
Maintain the Machine
Clean filters and carry out routine maintenance according to the instructions. Use the detergent and other products specified for your appliance.
Control Hot Water at the Sink
Use a bowl where practical and avoid leaving the tap running while doing something else.
Compare Like with Like
Judge each method against a similar quantity of dishes. Include any rewashing, rinsing and extra water needed.
For other household ideas, browse Stokes’ Home and Garden section. Its guide to keeping your home warm without turning up the heating covers another part of everyday home energy use.
Do You Need to Replace Your Dishwasher to Save Money?
A new model may have lower labelled consumption, but the purchase price also matters.
If your current dishwasher works well, compare the likely running-cost difference with the price of buying and installing a replacement. A small saving per cycle may take a long time to cover that upfront expense.
Consider the appliance’s condition, repair options and suitability for your household. Replacing a machine solely because another model has a better rating may not be the most economical decision.
Keep a note of the model number and consult its manual first. You can find more household and sustainability coverage on the Stokes homepage.
Frequently Asked Questions
Is a dishwasher always cheaper than washing up by hand?
No. It depends on the machine, load, programme and handwashing method. A full efficient cycle is a different comparison from running a nearly empty dishwasher for a few items.
Is it cheaper to use the dishwasher at night?
Only if your tariff offers a lower rate at that time. Check your tariff details, appliance instructions and fire-safety guidance before changing when you run it.
Does a quick dishwasher wash use less electricity?
Not necessarily. Programme duration alone does not tell you consumption. Check the energy figures in your machine’s manual.
Should I wait until the dishwasher is full?
Aim for a full, correctly loaded machine rather than an overcrowded one. Energy Saving Trust recommends full loads to help reduce unnecessary energy and water use. Energy Saving Trust
Is washing up in a bowl better than using a running tap?
A bowl helps control how much water you use. Energy Saving Trust recommends this approach as a way to reduce water and energy use. Energy Saving Trust
How can I find my dishwasher’s cost per cycle?
Use the programme’s kWh consumption and multiply it by your electricity unit rate. Add detergent and applicable water charges for a fuller estimate.
