How we test washing machines

We've been lab testing washing machines for more than 50 years, so we're well-versed in what separates the best from the rest. Today, we test almost 100 washing machines each year, conducting no fewer than 280 checks and assessments on every single machine.

We’re funded by Which? members and buy our machines direct from retailers. Not only does this prevent manufacturers from influencing our reviews, it also ensures we test exactly the same standard of machine that you would buy – nothing's been souped up to try and impress us. 

Our testing is completely independent and our verdicts are never for sale. If a machine falls down in the most important areas, we’ll label it with our Don’t Buy warning. 

Reviews you read elsewhere might be based solely on a single user’s initial impressions of a machine, rather than the thorough, independent laboratory tests and assessments carried out at Which?.

Nobody goes to the lengths we do to find the best washing machines.

Watch: How we test washing machines

Watch our video to learn more about the key elements of our rigorous test programme for washing machines. Scroll down for further information.

Overall cleaning: How well does the washing machine remove stains from clothes?

We wash more than 2,500kg of laundry every year, challenging each machine we test with a range of stains, including tough-to-shift blood, grease, ink, milk, oil and rust.

Our lab technicians load washing machines to 80% of their total capacity for the 40°C cottons program, since manufacturers generally advise leaving a hand's width of space at the top of the drum. Machines are loaded to the full capacity for the 30°C synthetics program, as they are generally designed to handle half the cottons capacity load. We run these programs at these temperatures because Which? members told us it's how they usually do their washing.

Test loads consist of a mix of real clothes that represent the laundry basket of a typical UK household. We attach stained fabric swatches to the clothes representing tough marks such as blood and grease. The same load type is used in each machine to ensure our results are comparable between machines.

We run our wash tests three times on each program using the same powder detergent, which is specifically formulated to an international standard for test laboratories under a strict recipe. Shop-bought laundry detergents are regularly reformulated, which means their performance can be inconsistent.

Lab technicians use a spectrophotometer to determine how much of each stain remains on our test fabrics. A light is shone onto the samples, and the photometer measures the light reflected back. The reflectance is measured on a spectrum from 0 to 100 – a lower number means the machine hasn't been effective at removing the dirt, whereas a higher number means the machine has powerful stain removal capabilities that leave little-to-no dirt on the items. 

If any of the wash or energy use results are wildly different between the three tests – or if one test run is much longer or shorter than the others – we carry out two further wash tests to ensure accurate results. 

What separates a good result from a poor one?

We rate a washing machine's overall cleaning ability between one and five stars. A five star machine is brilliant at removing a range of stains on the cottons and synthetics settings. A three star machine is not the best choice for heavy staining, but will get most clothes clean. Steer clear of one-star machines – these won't clean clothes to an acceptable standard.

Rebecca Jakeman, Which? washing machines expert, says:

'If a machine offers a dedicated stain-removal setting, we won't test this over the standard cottons program. We think a good washing machine should be able to tackle tough stains without the need for special programs. This also allows us to ensure our results remain as comparable as possible from one washer to the next.'

Rinse and spin: How well does it rinse away detergent and spin dry?

We go to real lengths to determine exactly how much detergent residue and moisture is left in a load of laundry at the end of a cycle. 

To measure how effective a washing machine is at rinsing away excess detergent, we add some cotton samples to each of our test loads. 

At the end of the cycle, they're collected with gloves, tweezers and scissors to avoid contamination. They're conditioned for 24 hours, weighed and put in a liquid solution to extract any remaining detergent residue before we analyse sulfonate (a type of salt) levels.

To rate how well each machine will spin-dry your clothes, our lab technicians weigh the clothes before they're loaded into the drum, and then again after they've been washed.

Most machines offer additional rinse or spin cycles, but we don't test these once the main program has ended.

What separates a good result from a poor one?

A machine that has been awarded one star for rinsing clothes might leave visible traces of detergent on your laundry, whereas models that deliver a five-star rinse are among the best we've seen at whisking away detergent from almost every fibre. A five-star spin dry will leave your load as dry as possible, saving you time on the washing line and energy if you use a tumble dryer.

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

Our tests have uncovered washing machines rated A for energy efficiency that actually cost significantly more to run than C-rated machines.

We don't rely on the energy label to tell us how efficient a washing machine will be – we run our own energy tests.

Our lab technicians record exactly how much energy and water a machine uses on both the cottons and synthetics programs. They then divide this by the drum capacity to reveal its efficiency.

A model with a cavernous 12kg-capacity drum is tested in the same way as a machine that can only hold 6kg of clothes. The bigger machine is likely to use more energy and water than the smaller machine, so our technicians divide energy and water use by the machine's capacity in kg to evaluate the results fairly.

We've seen machines that churn through more than 100 litres of water to wash a single load of clothes, as well as more economical options that use less than a third of this.

It's worth noting that we don't test eco programs or any other additional 'eco' features that claim to save you energy or water. The only exception is if the machine doesn't have a cottons cycle, in which case we use the eco program. But this happens very rarely.

What separates a good efficiency result from a poor one?

A machine that has been awarded one star for efficiency uses more energy and water than necessary, whereas three stars is about what we'd expect in terms of energy and water consumption. If a model is rated five stars, that means it's really efficient and won't unduly add to your bills.

Often, the more energy a washing machine uses, the better it is at cleaning. So it can be hard to find one that has a good balance of both. Those that pull this off get our Eco Buy recommendation.

Quietness: How noisy is it as it fills, washes, spins and drains?

A panel of three assessors rate noise levels during each stage of the cycle so you can find a machine that won't drown out your dinnertime conversation.

All washing machines can be noisy when they're running, but some are far louder than others, to the point where it makes carrying on a conversation or watching TV nearby difficult.

Some machines can go from a quiet, comfortable humming noise during the wash cycle to something that's almost as loud as a vacuum cleaner while they spin.

That's why we test how noisy each washing machine is as it fills, washes, spins and drains. Our expert panel monitors the normal operating noises using a decibel monitoring device. They also listen for any annoying sounds the machine might make.

While we plan to increase our accessibility coverage in the near future, we don't currently share much information on helpful noises. This may include tunes that play to let you know when a cycle has finished or beeps to help you work out which cycle you're selecting.

What separates a good quietness result from a poor one?

A five-star machine will be as quiet as a washing machine can be, while a one-star machine will make enough noise during use that you might find it hard to concentrate when you're in the same room. We'll let you know if a certain part of the cycle, such as spinning, is particularly intrusive too.

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

A team of three lab technicians rates how easy each machine is to use, ensuring laundry day isn't more of a chore than it needs to be.

We rate each washing machine we test on 16 different ease-of-use characteristics. These cover reading and understanding the instruction manual, loading and unloading clothes, using the detergent drawer, how clear the control panel and display are, plus how simple it is to select a wash program and generally operate the machine.

The lab experts also assess how straightforward you'll find regular maintenance tasks, from removing the detergent drawer for cleaning to emptying the fluff filter. The machines are presented to them in different orders to avoid bias. 

We find that most of you prefer to use the controls on the machine, so we don't currently test how easy it is to operate a machine from its smartphone app (if it has one). We'll look at updating the test if this changes in the future, though.

What separates a good result from a poor one?

A five-star machine will be intuitive and straightforward to use, usually with a wide-opening door and easy-to-remove washable sections. Three-star machines are generally user-friendly but may have a few niggles like sticky drawers or a door that requires a bit of force to open. A one-star machine will be a downright puzzle to operate.

Program length: How long do the main programs take to run?

We time the two main wash cycles so that you're not stuck waiting longer than you'd like for a load to finish.

Our lab technicians precisely time how long the cottons and synthetics programs take to run, and we give them a star rating relative to the capacity of the washing machine's drum. 

We expect larger-capacity models to take longer to wash a load of clothing, so we usually share a per-kilogram time as well as the total running time. As an example, you might need to run a 12kg machine twice a week but a 7kg machine three to four times for the same amount of laundry. 

The fastest washing machine we've tested finished a 10kg cottons load in just one hour 13 minutes, whereas one of the slowest took almost five hours to wash 9kg.

Speed isn't everything though, as we sometimes find that quicker machines can fall down in our stain-removal testing. 

We don't currently assess quick programs or smaller-load options as part of our main test. However, we sporadically run extra testing specifically on quick washes and find them to be less effective than the main program.

What separates a good result from a poor one?

A one-star washing machine will take an age to get clothes clean – we've tested models that take 40 to 50 minutes to clean a single kilogram of cottons. Machines scoring five stars will whizz through a load in a flash, with the quickest we've tested taking less than 15 minutes per kilogram of cottons.

Which? members can filter all our washing machine reviews by overall cleaning, ease of use, quietness and more of our expert test results

How we calculate the scores

Olivia Pratt, Which? scientific advisor, says: 

'We regularly ask Which? members what matters most when choosing a washing machine. I then use this information when developing the test programme and evaluating the data from the laboratory. Since members said cleaning matters most, it carries more weighting than other elements of the testing when calculating the score.' 

Here are the weightings for each element of the test:

• 40% overall cleaning 
• 15% rinsing efficiency
• 15% spin drying
• 10% energy and water use
• 7.5% program length
• 7.5% ease of use
• 5% quietness

How we choose the products

To make sure our reviews are 100% independent, we never accept free product samples from manufacturers or brands. Instead, we invest nearly £40,000 every year buying washing machines directly from major retailers.

We test almost 100 new washing machines a year, with scope to include more if there are products we simply can't ignore. And we test products almost every month of the year, so that we can deliver our verdicts as quickly as possible.

We also cater to a range of budgets, from less than £300 to over £1,000. Everything from basic, no-frills machines to all-singing, all-dancing models will make their way through our test lab in any given year. This means we can showcase premium Best Buy models alongside Great Value machines that punch above their price tag.

Adishree Sharma, Which? Market analyst, says:

'To offer the best market coverage, I choose products from popular washing machine brands like Bosch, Hotpoint and Miele, and try to find all the key models you'd see at major retailers like AO, Currys or John Lewis. We don't just test the flagship models that companies want to promote – I actively track UK new launches, market trends, consumer search habits and sales data to ensure we test the machines people actually buy.'

Is it a Best Buy washing machine? What our verdicts mean

Our recommendations should help you to narrow down your shortlist, but it's always best to read our reviews in full to check for any dealbreakers before parting with your hard-earned cash.

Best Buy washing machines

Best Buys are awarded to washing machines that impress us most in our tests. A machine must score 75% or more to earn our Best Buy accolade. 

They excel at removing stains from cottons and artificial fibres, plus they have excellent rinse and spin cycles and are easy to use.

Eco Buy washing machines

Eco Buy washing machines use less energy and water than other models we've tested, so they'll have a lower environmental impact over their lifetimes.

To earn our Eco Buy badge, a washing machine must have:

• a test score of at least 60% 
• three stars or more for energy efficiency on both cottons and synthetics washes
• three stars or more for water on both cottons and synthetics washes
• four stars or more for cleaning on both cottons and synthetics washes
• a good brand reliability record in our annual survey (discover which washing machine brand is the most reliable). 

Great Value washing machines

To be highlighted as a Great Value washing machine, a model must be markedly cheaper than the average price for tested models of the same type, whether that's freestanding or integrated – helping you clean your clothes without breaking the bank.

They must also score at least 65% in our tests and achieve four out of five stars for overall cleaning, energy efficiency and water use. 

Don't Buy washing machines

Washing machines that score 45% or below are highlighted as Don't Buy models that we think you should avoid. 

Don’t Buy washing machines tend to fall down in the most important areas. Think ineffective stain removal, spinning too slow to be effective and detergent left on clothes after rinsing.

Discover which models impressed in our lab in our washing machine reviews – use the Best Buy, Eco Buy and Great Value filters to help find the right model for you.

Our washing machine experts

Running our test projects is a group effort, with several members from across the team contributing to each one. 

We thoroughly re-evaluate our testing processes every year to ensure it's useful to you, and we ask the Which? community to tell us what matters the most when choosing a new washing machine.

Here's the team that makes it happen:

• Senior researcher & writer, Rebecca Jakeman: Rebecca translates technical laboratory metrics into in-depth, unbiased product reviews and advice to separate the stellar washing machines from the duds. She cuts through the marketing fluff and confusing jargon to ensure you invest in a machine that actually delivers on its promises.
• Home editor, Victoria Purcell: Victoria makes sure what you're reading is exactly what you want to know about washing machines. This means keeping a close eye on what's trending in the laundry space, seeking out key consumer questions we can help answer and finding new stories from our data to help empower our readers.
• Scientific advisor, Olivia Pratt: Olivia helps to shape our test programme, and meticulously converts hundreds of data points for each washing machine into easy-to-understand product scores and star ratings. Her rigorous analysis ensures that only the cream of the crop are awarded our Best Buy or Eco Buy badges, while underachievers are marked as Don't Buys.
• Market analyst, Adishree Sharma: Adishree keeps her finger on the pulse of what's happening in the washing machine world to curate our testing line-up, ensuring we only review what’s relevant to you. From machines by major household names to rising stars, we look beyond the marketing hype to test what you want to buy next.