How we test washer-dryers

We've been lab testing washer-dryers since the 1960s, so we can confidently say we're great at separating the best from the rest. Today, we conduct no fewer than 300 checks and assessments on every single washer-dryer that we send to our test lab.

We buy every appliance direct from retailers, just as you would. Not only does this mean manufacturers can't influence anything we say in our reviews or advice, it also ensures we test exactly the same standard of washer-dryer that you would buy – nothing's been rigged to try and impress us.

Our testing is 100% unbiased and our recommendations are never up for sale. If a machine fails to perform as it should, we won't hesitate to make it a Don't Buy.

If you read a review elsewhere, you can never be sure if the verdict is the tester's personal opinion, or an objective, thoroughly researched conclusion. With Which?, you're getting results based on rigorous, independent laboratory tests and assessments developed by experts.

See our best washer-dryers to find out which models give top-class results.

Cleaning power: How good is the washer-dryer at removing dirt?

We challenge each washer-dryer we test with a range of tough-to-remove stains, including chocolate, oil, blood and red wine.

Our lab technicians load washer-dryers to 80% of their stated capacity for the 40°C cottons program, as manufacturers usually advise leaving some space at the top of the drum to allow items to circulate properly. Machines are loaded to their full capacity for the 40°C synthetics program, as they are designed to handle half the cottons capacity as standard. We test at these temperatures because Which? members told us they're the ones they use most often. 

Our standardised test loads contain real items to represent a typical laundry basket. This includes shirts, jeans and towels, as well as stained fabric swatches to represent tricky-to-shift residues like blood, oil and grease. These loads remain uniform from one washer-dryer to the next to ensure all our results are comparable.

We run the test washes twice on each of the main programs, using specially-formulated detergent that meets the international standard for test laboratories. This is because detergents you can buy in the supermarket are regularly reformulated, so consistent performance isn't guaranteed from one batch to the next. 

Lab technicians use a spectrophotometer to assess exactly how much of each stain remains on the test fabrics after washing. They shine a light onto each sample and measure how much is reflected back on a scale from 0 to 100. A lower number means the washer-dryer hasn't done a great job of shifting the dirt, whereas a higher one means it has been pretty effective at eradicating most or all of the stain. 

If any of the stain removal, water or energy use results vary wildly between the tests, we carry out an extra test wash to ensure accuracy. 

What separates a good cleaning result from a poor one?

Each washer-dryer receives a rating from one to five stars for both its cottons cleaning and synthetics cleaning performance. A five star machine is excellent at removing almost every stain , while a one star model will struggle to get your clothes clean to an acceptable standard. Often, machines will perform better on one program than the other, but our top performers will be pretty consistent across both. 

Rebecca Jakeman, Which? washer-dryers expert, says:

'We test the standard cottons and synthetics programs instead of any dedicated stain-removal cycles, as we think a good washer-dryer should have the ability to remove tough dirt and grime without any special extras. Using the standard programs also helps us ensure our results remain as comparable as possible between various models.'

Rinse and spin: How well does it rinse away detergent and spin off excess water?

We analyse samples thoroughly to provide an accurate picture of just how much moisture and detergent residue each washer-dryer leaves behind once the cycle finishes. 

To assess just how effective a washer-dryer is at rinsing away excess detergent, we add some cotton samples to each of our test loads. 

Once the cycle has finished, our lab technicians remove them from the drum using gloves, tweezers and scissors to reduce the risk of any potential cross-contamination. They're conditioned for 24 hours, before being weighed and put in a liquid solution to extract any remaining detergent residue. We then analyse the sulfonate (a type of salt) levels in each item. 

To measure how well each machine spin dries, we weigh the clothes before they're loaded into the drum, and again once they've been washed. We do this on both the main cottons and synthetics programs.

The majority of washer-dryers offer additional rinse or spin cycles, but we only test the main programs so that our results are comparable.

What separates a good rinse and spin result from a poor one?

Machines that receive one star for rinsing clothes are likely to leave visible traces of detergent on your clothes, whereas five-star models will do a great job of eradicating almost every last bit of detergent. A one-star spin dry will mean your items will emerge from the wash cycle damper than necessary, and take longer to dry, whereas five-star models will help you reduce drying time (and energy use during the drying cycle).

Dryness of clothes: Can the washer-dryer dry thoroughly and evenly?

We dry almost 150 loads of laundry each year, measuring just how dry your clothes will get using the main cottons and synthetics programs.

Our lab technicians load each washer-dryer to its stated capacity on the 'ready to store' cottons and synthetics programs. Synthetics cycles can usually handle around 50% of the total cottons capacity. We test using these specific programs (or the closest equivalents if they aren't available) as Which? members told us they're the ones they prefer to use.

The test laundry loads are the same throughout our washing and drying assessments, so drying programs are rated on their ability to dry a mixture of shirts, jeans and towels, alongside other items. Our lab technicians weigh the contents of each load after they've been washed, and then again after they've been dried, to see exactly how much water each washer-dryer removes.

As the humidity levels of each load can vary depending on the effectiveness of each machine's spin drying, we meticulously measure the humidity of each item before and after the drying program, as well as comparing this with the humidity levels of the complete load. This helps us work out whether or not a model is able to dry each item of clothing evenly, or if items stuck in the middle will still be damp when the buzzer sounds.

We run each drying test twice on both the cottons and synthetics programs. If any of the drying performance or energy use results vary too much between the two tests – or if one cycle is much quicker than the other – we carry out a further cycle to double check the results. 

What separates a good drying result from a poor one?

Our washer-dryers receive two star ratings: one for dryness of clothes and one for drying evenness. A machine that receives a perfect five stars will dry a full load completely evenly, leaving no damp spots, but a one-star model could result in your laundry emerging from the drum half-wet and half-dry. 

Program length: How long does it take to clean and dry your clothes? 

We time both the cottons and synthetics washing and drying cycles so you know exactly how long each machine will take to tackle a full load.

Our lab technicians time, to the minute, how long the main washing and drying programs on each machine take to run. We then award them a star rating for washing and drying, relative to the total capacity of the machine's drum.

It's no secret that larger models will usually take longer to wash a full load of clothing, so we tend to share a per-kilogram washing and drying time as well as the total time for each. A model with 12kg washing capacity might only be run twice a week, whereas you'd need to use a 7kg model three to four times to tackle the same amount of laundry.

The speediest washer-dryer we've tested washed a cottons load in just an hour and 11 minutes, whereas one of the slowest took over four hours. A quick washer-dryer might take just over two hours to dry a 6kg load of cottons, but land yourself a slower one and you could be waiting as much as seven hours for the same size load.

It's all about balance, too, as often super-speedy washer-dryers compromise on stain removal, drying evenness, or both, where models that take slightly longer do a more thorough job. 

While we don't assess quick-wash or quick-dry programs on a regular basis, we do carry out occasional extra testing that shows them to be generally less effective and less efficient than the main programs. 

What separates a good speed result from a poor one?

A machine that scores just one star for its program length will take far longer than it should to get your clothes clean and/or dry - we've seen models that take 33 minutes to wash just one kilogram of cottons. Washer-dryers scoring a perfect five stars won't keep you waiting, with the quickest we've tested cleaning a kilogram in 13 minutes on the cottons program. 

Wash and dry: Is it effective, speedy and efficient on the wash and dry cycle?

We run the designated wash-and-dry program on each machine (if it has one) so you know exactly how quick and effective it is at getting a load of clothing washed, dried and ready to wear.

For the machines that have a wash-and-dry program, our lab technicians run it at its full capacity. Sometimes machines have programs designed for smaller loads of around 1kg, whereas others might be able to handle a full load of 8kg or more. 

We rate each machine on how long it takes to wash and dry the full-capacity laundry load, as well as how well it removes stains and whether or not it's able to dry each item evenly. Essentially, we cover all of the same metrics as we do in the separate washing and drying tests aside from spinning efficiency, since there's no break between the washing and drying parts of the program for us to remove and weigh the clothes.

We also score each model on how much water and energy it uses, and present a combined metric that covers both the washing and drying phases. 

What separates a good wash & dry result from a poor one?

A washer-dryer that scores a perfect five stars will be able to get your clothes clean and dry without taking an age, or using too much energy or water in the process. Machines that score one or two stars often fail to get clothes clean or dry (or both) and use more energy than neccessary. 

Energy and water use: How efficient are the main programs?

Our tests have uncovered A-rated washer-dryers that actually cost much more to run than C-rated models due to poor water and energy efficiency.

We don't rely on the energy label to tell us how efficient an appliance will be. Plus, we know from our running cost data that washer-dryers are the most expensive appliances to run by quite a margin.

Our lab technicians measure exactly how much water and energy each machine uses during both the cottons and synthetics programs. They then divide this total number by the capacity of the drum to reveal its efficiency. 

Whether they have a generous 12kg drum or a more modest 7kg offering, all washer-dryers are tested in the same way. While the bigger machine is almost definitely going to use more energy and water to clean and dry your clothes than the smaller machine, our technicians give us a 'per kilogram' measurement so we can evaluate the results fairly. 

We've seen washer-dryers that go through almost 150 litres of water to wash a single cottons load, as well as more eco-friendly options that use less than half of this.

We don't test eco programs or any other 'eco' features that promise to save you energy or water, as our members have told us they don't use these very often. The only exception is if a washer-dryer doesn't have a cottons cycle, in which case we will use the eco program. But this happens very rarely.

What separates a good efficiency result from a poor one?

A machine with a one-star efficiency rating uses much more energy and water than necessary, whereas a five-star model is really efficient and will keep household bills in check. We find that washer-dryers that use more energy are often better at cleaning and drying, so it can be hard to find a machine that balances both. That's where our Eco Buys come in. 

Ease of use: Is it intuitive and straightforward to use?

Three lab technicians rate the usability of each washer-dryer we test on more than 50 separate ease-of-use characteristics.

We score models on how straightforward it is to load and unload clothes, how well the detergent drawer slides in and out, the clarity of the control panel and display, plus how simple it is to select and start your chosen program. We also make sure the instruction manual is clear and understandable.

The lab technicians also carry out regular maintenance tasks to assess how easy they are to perform, from emptying the fluff filter to ejecting the detergent drawer so you can give it a good scrub. Each technician sees every washer-dryer in a different sequence to avoid any accidental bias.

When it comes to smart appliances, we don't currently test how easy it is to control a washer-dryer from a smartphone app. This is because most Which? members told us they prefer to use the control panel on the machine itself. However, should this change, we will update our test protocols accordingly.

What separates a good ease of use result from a poor one?

A machine that scores five stars will be overall user-friendly and easy to clean, generally with a wide-opening door and well-labelled control panel. Three-star washer-dryers might have a few usability niggles like a sticky detergent drawer or door that's hard to open, while one-star models will make laundry day more of a chore than is necessary.

Quietness: How noisy is it while running?

Three assessors rate noise levels as each machine washes, spins and dries to help you find a machine that won't interrupt your chats over the breakfast table.

It's impossible to find a washer-dryer that makes no noise whatsoever, but some are much quieter than others. Some machines are unintrusive as they wash your clothes, only to ramp up the volume and sound like they're about to take off during the drying process. That's why we test how loud each washer-dryer is as it washes, spins and dries. 

As well as using a decibel monitoring device, our panel of experts independently rate every machine on overall quietness, as well as noting any particularly annoying sounds they might make. 

A handful of machines include accessibility features like playing a tune to let you know a cycle has finished, or beeps to confirm which program you're selecting. We don't routinely share information on these, unless there's something particularly standout, but we do plan on increasing our accessibility coverage in the near future.

What separates a good quietness result from a poor one?

A five-star-rated washer-dryer will be about as quiet as you can get, while a machine scoring just one star will make enough noise throughout the cycles that you might struggle to focus on anything else. 

Which? members can filter all of our washer-dryer reviews by cleaning performance, energy efficiency, quietness and more of our expert test results

How we calculate the scores

Each year, we re-evaluate the way we test to ensure our methods are as relevant as possible, speaking to the Which? community to discover what matters most when choosing a new washer-dryer.

Olivia Pratt, Which? scientific advisor, says:

'Our regular surveys tell us what matters most to Which? members when choosing a new washer-dryer. This information helps me to develop the test programme and evaluate all of the data we receive from the laboratory. Since members have told us washing, rinsing and spin drying are most important to them, these elements of the test carry the most weighting when calculating the score.'

Here are the weightings for each element of the test:

• 40% washing, rinsing and spin drying (includes energy and water efficiency)*
• 25% wash and dry program (includes energy and water efficiency)*
• 15% drying speed, evenness and accuracy (includes energy and water efficiency)*
• 15% ease of use
• 5% quietness

*We run our efficiency assessments during each of these elements of the test and then average out the scores to give us a star rating for energy use and water use.

How we choose the products

Our reviews are always 100% independent, because we never accept any free product samples from brands or manufacturers. Instead, we spend around £12,000 each year buying washer-dryers directly from major retailers – the same way you would.

We test a batch of washer-dryers every quarter, so we can deliver our verdicts in a timely manner. 

Everything from simple, no-frills machines to premium models with advanced features will make their way through our test lab in any given year. We test models from £300 all the way up to over £1,000, and sometimes we find cheaper models that match or outperform more expensive options.

Adishree Sharma, Which? market analyst, says:

'To offer the best market coverage possible, I choose products from popular washer-dryer brands like AEG, Hotpoint and Bosch, and try to find all the key models you'd see at major retailers like AO, Currys or John Lewis. We don't just buy the flagship models that companies want to promote either – I actively keep an eye on new UK launches, market trends, consumer search habits and sales data to ensure we test the machines that you're actually interested in.'

Is it a Best Buy washer-dryer? What our verdicts mean

Looking at Best Buy machines should help you compile your washer-dryer shortlist, but we'd always advise reading our full reviews to check there aren't any dealbreakers before you make your final decision.

Best Buy-recommended washer-dryers

Best Buys are awarded to washer-dryers that impress us most in our tests. A washer-dryer scoring more than 70% will be a Best Buy and comes with a firm recommendation. 

They offer outstanding stain removal from cottons and manmade fibres, plus they're quick, accurate and even at drying and easy to use too. 

Eco Buy-recommended washer-dryers

If your washer-dryer is due an upgrade and you're trying to make more eco-friendly choices, look out for our Eco Buy models. Eco Buy washer-dryers will have a lower environmental impact over their lifetimes compared to other models we've tested.

To be 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 rating in our regular survey (discover which washer-dryer brand is the most reliable).

Great Value-recommended washer-dryers

To become a Great Value washer-dryer, a model must score at least 60% in our tests. They must also achieve four out of five stars for cottons cleaning, energy efficiency and water use, and three out of five stars for dryness of clothes and drying evenness.

All of our Great Value washer-dryers are notably cheaper than the average price for tested models of the same type, whether that is integrated or freestanding, so you can get your clothes clean and dry without spending a fortune.

Don't Buy washer-dryers

Washer-dryers that score 45% or below in our tests are highlighted as Don't Buy models we think you should avoid. 

Don't Buy washer-dryers tend to underperform in the key areas of our testing. Think lacklustre stain removal, uneven drying and ease of use issues. 

Find out which models impressed in our lab in our washer-dryer reviews – use the Best Buy, Eco Buy and Great Value filters to help find the right model for you.

Our washer-dryer experts

Our testing projects are a real group effort, bringing together research and content specialists to analyse and present our results in a way that's comprehensive yet easy to understand. Here's the team behind it all:

• Senior researcher & writer, Rebecca Jakeman: Rebecca translates technical lab data into clear, unbiased reviews and practical advice. By cutting through marketing hype and jargon, she helps you separate standout performers from duds so you invest in a machine that actually delivers.
• Home editor, Victoria Purcell: Victoria ensures our content answers the exact questions you're asking. She stays on top of laundry trends, addresses key consumer queries, and pulls insightful stories from our data to help guide your buying decisions.
• Scientific advisor, Olivia Pratt: Olivia helps shape our testing program, turning hundreds of data points per machine into simple star ratings and scores. Her rigorous analysis ensures only top-tier models earn our Best Buy or Eco Buy awards, while underperforming machines get tagged as Don't Buys.
• Market analyst, Adishree Sharma: Adishree tracks industry movements to curate our test lineup, ensuring we review the models most relevant to you. From major household brands to emerging names, she looks past the commercial hype to test what you actually want to buy next.