Washer-dryer or washing machine and tumble dryer: which is more cost-effective?

If you're short on space for a standalone tumble dryer, but want to dry your clothes, bedding and towels quickly, should you buy a washer-dryer?

To find out how using a washer-dryer compares to a separate washing machine and tumble dryer setup, we've compared the prices of each and analysed Which? test data to calculate how much they cost to run, as well as how effectively and efficiently they will wash and dry your laundry.

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Is it cheaper to buy a washer-dryer or a washing machine and tumble dryer?

It sounds like a no-brainer that buying two appliances will cost you more than buying one, but actually that's not always true. 

At the time of writing, it's cheaper to buy a washer-dryer than a washing machine and tumble dryer, whether you want a Best Buy or you're expanding your search to include all of the models we've tested. 

• The cheapest washer-dryer we've tested costs £369. The cheapest washing machine is priced at £210 and the cheapest tumble dryer costs £200, which totals £410. That makes buying a washer-dryer £41 cheaper.
• The cheapest Best Buy washer-dryer we've tested costs £389. The cheapest Best Buy washing machine is £419 and the cheapest Best Buy tumble dryer is £399, which equals £818 in total. That makes buying a Best Buy washer-dryer £429 cheaper.

However, when we've run this pricing analysis in the past, it has at times been cheaper to buy two good standalone models than one washer-dryer – and, even when more expensive, the window has been much narrower. 

That's because:

• These machines are often on sale, so you may well get a great washing machine deal or tumble dryer deal.
• There are fewer washer-dryers on the market than washing machines and tumble dryers, meaning fewer really good models and less choice.

In short, buying a washer-dryer may well be cheaper, but don't necessarily assume that's the case. We'd advise checking our reviews and prices at the time you're ready to buy. 

And consider energy and water costs – as well as how much space you have in your home – before deciding. 

Compare our pick of the best washer-dryers with the best washing machine deals and Great Value tumble dryers.

Do washer-dryers use more energy than washing machines and tumble dryers?

Yes. Based on the new energy price per unit of 24.5p per kWh (from April 2024), a heat-pump tumble dryer will cost you £49 a year to run, on average, and a washing machine will cost you £56 a year, on average. So the two combined will cost you almost £105 a year in running costs. 

The average washer-dryer will cost you £65 on average for washing costs, and £133 in energy costs for drying – so £198, on average – which is £93 more.

That's based on running the 40ºC cottons program four times a week for a year (for washing machines and washer-dryers) and running the cottons cupboard-dry program on a tumble dryer three times a week for a year. 

Clearly, your costs will be higher if you wash or dry your laundry more often than that. 

If you decide to go for a washing machine and tumble dryer combo, we strongly recommend getting a heat-pump tumble dryer.

Condenser tumble dryers use significantly more energy. You'll be spending, on average, around £120 a year in running costs in the scenario we described above, compared to the £49 we calculated for a heat pump.

Find out more about the differences between heat-pump, condenser and vented tumble dryers, and when a heat-pump tumble dryer will pay for itself in saved energy costs.

Do washer-dryers use more water than washing machines and tumble dryers?

On average, a washing machine uses 11.29 litres of water per kilogram of cottons, whereas a washer-dryer uses 12 litres. 

That might not sound like a big difference. But if you're washing 5kg of cottons four times a week, for example, you'd be using 738 litres more water across the year with a washer-dryer. Water shortages in recent years have brought home how much that matters. 

You might be surprised to know that washer-dryers also use water for drying clothes – 7.5 litres per kilogram of cottons. The cold water is used to help the condensation process that cools the air and condenses the water vapour from your wet laundry to dry it. 

So drying 5kg of cottons three times a week (an average-use scenario, according to our research), you'd be using 5,850 litres of water across the year. 

As with energy, you'll have to scale that up if you're washing and drying more often, or down if it's much less. 

Eco Buy washer-dryers

If you want to make a more sustainable choice when you're buying your next washer-dryer, a Which? Eco Buy is a good option, as it will have a lower impact on the environment over its lifetime than other washer-dryers.

We calculate this in two ways: how energy-efficient it is and how little water it uses. Because of this, you can expect an Eco Buy washer-dryer to save you money on your bills as well as reduce your environmental impact. This is especially handy when you consider that washer-dryers use more water and energy than washing machines and tumble dryers.

To become an Eco Buy, a washer-dryer must have:

• A test score of at least 65%
• Four stars or more for water use
• Four stars or more for energy use during washing
• Three stars or more for drying performance on both cottons and synthetics
• A good brand reliability record in our annual washer-dryer owner survey

Only around 5-10% of washer-dryers are sustainable enough to be Eco Buys. To find out which did enough in our tests to earn this badge, head to our washer-dryer reviews and use the Eco Buy filter.

Do washer-dryers wash well?

Good washer-dryers are pretty much on a par with good washing machines when it comes to cleaning. 

Both generally handle stained synthetics well but can struggle with heavily stained cottons. 

They usually take three to four hours for a cottons wash, and one-and-a-half to two hours for a synthetics wash.

Do washer-dryers dry well?

For drying, it's a different story. Washer-dryers are often nowhere near as good as tumble dryers. 

Almost all washer-dryers have sensor-driven automatic drying programs. But these often aren't very accurate. In other words, they overestimate or underestimate how long they need to dry your washing for. This isn't ideal if the clothes you were hoping to wear are still sopping wet or have shrunk to no longer fit you. 

Washer-dryers usually have a smaller drying capacity than tumble dryers, although some Best Buy washer-dryers can dry as much as a tumble dryer. 

Washer-dryers also have a smaller capacity for drying than washing. This means that if you fill your machine to capacity each time you do a wash, you'll have to take some of it back out before drying. 

One small advantage of a washer-dryer is that the water that's extracted from your clothes in the course of drying will be drained away automatically. You won't have to empty it out yourself, as you would with a heat-pump or condenser tumble dryer. 

Which? washing machine and washer-dryer reviews

We test washing machines, washer-dryers and tumble dryers regularly across the year. 

Our latest washing machine reviews feature models from AEG, Bosch, John Lewis and LG. Among them are Best Buys (the absolute best for performance), Eco Buys (models that combine good performance with a smaller environmental impact) and some less impressive models. 

We also recently added to our washer-dryer reviews with new models from Beko, Bosch, Hotpoint and other brands. Some were fantastic models while others were let down by ineffective washing or drying. 

Our latest tumble dryer reviews include models from Bosch, Swan and Zenith. Among them was a Best Buy and two Eco Buys, but some were deemed rather noisy.

Which? verdict: are washer-dryers any good?

Most washer-dryers do a poor job of drying compared with dedicated tumble dryers. 

Go for a separate washing machine and tumble dryer if you have the budget and the space at home. 

As we said before, there are more washing machines and tumble dryers on the market than washer-dryers, so as a bonus you can be choosier when it comes to colour or extra features. Go for a washer-dryer and you're stuck with a more limited pool of models to pick from. 

If you've reviewed the options and decided that a washer-dryer is the most suitable option for you, make sure it's one of the best. Best Buy washer-dryers do a much better job of washing and drying clothes than others. 

If you don't have room for a tumble dryer, but don't want to buy a washer-dryer, you'll of course need somewhere to hang your wet washing. 

The best place to hang it is outdoors, as this reduces the chances of moisture build-up and mould inside your home.

If you don't have an outdoor space where you can hang a clothes line, try one of our picks of the best heated clothes airers, and combine it with a Great Value dehumidifier to speed up the drying time. Follow our guidance on how to dry clothes indoors during the winter.

Whether you buy a washing machine and tumble dryer or a washer-dryer, you'll save on water and energy if you choose an efficient appliance.

It can be hard to find appliances that are effective but don't use much energy or water – some are frugal with one or both of these, but simply don't clean that well. 

Use our washer dryer reviews, tumble dryer reviews and washing machine reviews to find the best. Some tumble dryers and washing machines are good enough to earn our Eco Buy recommendation, combining good performance with relatively low water and energy use. 

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Model prices correct as of 25 August 2023. Energy costs were updated on 25 August 2023 in line with the new energy price cap announcement for October 2023.