A friend of mine told me that it is cheaper and more energy efficient to use a dishwasher than to wash up by hand.
She also said that to be as energy efficient as possible you shouldn’t even rinse the plates before loading a dishwasher, just scrape off food into the bin.
Is it really true that it is cheaper to use a dishwasher than wash up by hand – and wouldn’t failing to rinse plates cause the dishwasher to get blocked up? Via email
Dishwasher or sink? Experts agree that using the dishwasher is more efficient than doing the washing up by hand
Helen Kirrane of This is Money replies: The cost of living crisis is leading many households to throw the kitchen sink at reducing their bills.
Everyone has a view on whether it is cheaper to wash up by hand in the sink or use a dishwasher, so we put this to the experts to find out once and for all.
Which is cheaper – sink or dishwasher?
There are two big things to factor in with working out which is cheaper – the cost of water, and the cost of heating that water.
Contrary to popular belief, dishwashers use less water than sink washes.
The average dishwasher uses 10 litres of water each time it runs – while filling a standard sink just once would use nine litres of water.
Why are energy bills so high?
Since coming out of the pandemic demand for gas has gone through the roof, but supply has struggled to catch up. It has sent prices soaring and pushed up the cost of gas and electricity for both households and businesses.
This has been compounded by Russia’s invasion of Ukraine.
One dishwasher can hold two to three washing up bowlfuls of crockery and cutlery, meaning 10 litres of water in a dishwasher cleans the same amount of items as 27 litres in a sink.
The overall cost of washing up depends not only on the amount of water used, but also how much it costs to heat it up.
But the dishwasher beats the sink when it comes to energy use, too.
Ben Gallizzi, energy expert at comparison site Uswitch, says: ‘It might seem surprising, but modern dishwashers are more efficient than hand washing for both water and energy use if washing a full load.
‘Filling a nine-litre sink with hot water could cost just under 16p to heat – but it’s unlikely that you’ll be able to wash a dishwasher’s worth of dirty dishes in the same water, making the appliance a better option overall’.
‘While one wash in a dishwasher would cost around 26p in energy, and will generally do all the dishes used by the average household in a day.’
In other words, washing up by hand costs between 32p and 48p a day (for two or three sinks’ worth of items), whereas using a dishwasher for one load costs 26p.
> We explain how to work out what an appliance costs to use
However, there are plenty of variables, such as the size of your dishwasher and sink, and the cost of washing up liquid, dishwasher tablets, rinse aid and dishwasher salt.
If you are washing dishes by hand, the Energy Saving Trust charity recommends that you should always use a bowl, rather than a constantly running tap.
You could also consider fitting an aerator onto your existing kitchen tap to reduce the amount of water coming out without affecting how it washes or rinses.
An aerator is a small gadget with tiny holes that work by attaching to the spout of taps and adding air to the flow of water.
These use less water and can save you £30 a year on your energy bills according to the Energy Saving Trust.
Tap out: Pre-rinsing plates before putting them in the dishwasher should be kept to a minimum, as this can rack up bills
Should you rinse your plates?
Pre-rinsing heavily food-covered dishes can help stop food waste clogging your dishwasher filter, but remember that running the hot tap will cost you money.
‘Try to scrape off the leftovers or give them a quick cold water rinse if needed,’ Gallizzi says.
‘Research suggests a running hot tap can use 100 litres in just ten minutes, while most dishwashers use less than 10 litres per cycle, so keep any pre-rinsing to a minimum.’
How to run your dishwasher efficiently
Reducing your dishwasher use by one cycle a week could save you £17 a year on your energy bills, according to the Energy Saving Trust.
Running your dishwasher when it is half empty is a waste of energy, so wait until you have a full load before you use it.
By filling your dishwasher up to a full load, you will use less water than if you were to fill up the sink, according to A-Plan Insurance.
There are additional ways to save energy costs when buying a dishwasher or any other new appliance.
Alex Hasty, director at comparison website ComparetheMarket, suggests choosing a model with the highest energy rating.
A is the most energy-efficient, while G is the least.
Also keep in mind that your dishwasher may have an eco option, which should help to keep energy use lower overall.
> Should you spend £229 or £2,149 on a washing machine? We reveal if an expensive energy efficient model is worth the money in the long term