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How we test cordless vacuums
Journalist with four years’ experience researching and writing tech and home content. No detail goes unnoticed when it comes to dishwashers, vacuums and headphones.
In this article
- Carpet cleaning: Does it remove dirt and pet hair from deep within the pile?
- Hard floor cleaning: How well does it deal with on floorboards and laminate?
- Cleaning with a full dust container: Does the suction drop?
- Allergen retention: How well does the filter trap allergens?
- Ease of use: Is the vac easy to manoeuvre and handle?
- Battery life: How long does the battery last?
- Noise: Does it make a racket while running?
- Energy consumption: Does the vacuum use too much energy?
We test nearly 50 vacuums in our lab each year, conducting more than 150 checks and assessments in categories such as cleaning, suction and battery life.
Which? is an independent consumer champion. We buy our own cordless vacuums direct from retailers, just as you would – and we don’t accept freebies from manufacturers or retailers. This enables us to share honest reviews and impartial advice that is genuinely helpful to you, the consumer. If it’s rubbish, we’re not shy about giving it a Don’t Buy warning.
Many online cordless vacuum cleaner reviews use an individual tester to generate scores based on that individual's experience and preferences. But we don't deal in opinions, we deal in evidence, so we strap each vac into a custom-built rig to test it under laboratory conditions.
Find out which models nailed our tough tests in our guide to the best cordless vacuum cleaners
We’re not influenced by third parties and we don't accept freebies from product manufacturers or retailers. As a not-for-profit organisation, we have no owners, shareholders or government departments to answer to, so we work entirely on behalf of you, the consumer – nobody else.
Read our full statement of editorial independence.
Carpet cleaning: Does it remove dirt and pet hair from deep within the pile?
We embed a dust mixture, fine Arizona sand and real cat and dog hair into a Wilton carpet and then test how well the cordless vacs lifts each of them out. Our tests are extensive – we consider the push force, the appropriate nozzles to use and power settings.
Our lab technicians strap vacuums into a custom-built rig so that, when testing how much dirt they pick up in both forward and backwards motions, the speed and pressure of the vacuum is equal across all of our tests.
We comb sand and fur into Wilton carpet (a popular type of woven carpet), and deeply embed a dust mixture, to test how long it takes the vac to lift them all out. We found one vac that took more than three minutes to pick up the pet hair, while the best took just 42 seconds.
Each vac gets five passes at the dirt, to give it a fair chance of sucking it up, and the test is repeated at least twice for accuracy.
We also test how well the vacuum removes fibres from upholstery, using the relevant nozzle. We run it over a cushion and record how long it takes to remove the fibres – some suck it up in just 11 seconds, while others take more than three minutes. Some vacs fail to remove it at all.
What separates a good result from a poor one?
A good vacuum lifts most of the sand, dust and pet hair from carpet within five passes. A vac that scores five stars for carpet cleaning will banish dirt quickly, whereas a one-star vac will leave most of the dirt on the carpet sample. We found that the top-rated vacs suck up around eight times more dirt compared to the worst.
Hard floor cleaning: How well does it deal with on floorboards and laminate?
We test how well cordless vacuums suck up large debris, such as rice and lentils, from laminate and floorboards – as well as dust from between those pesky cracks in floorboards.
Our hard floor tests cover both laminate and wooden floorboards, which often have deeper crevices and cracks that can trap dust and dirt. Lab technicians carry out a maximum of five passes on each surface type, and then weigh how much dust each vacuum has sucked up from the crevices.
To test how well each model sucks up large debris, we spread a 50:50 mix of rice and lentils across the test area. Some cordless vacuums suck up most of the debris, while others push the rice and lentils around, or it flies off the test area. This is usually the case if the floorhead is too low or the rolling brush scatters the debris instead of guiding it into the vacuum.
Many vacuums claim to have edge-to-edge cleaning, so we test how close to wall edges and corners the vac is able to clean using the main floorhead. We measure the dust the vacuum fails to pick up from the front, right and left sides of the test area. Some vacs leave as much as a 2cm gap.
What separates a good result from a poor one?
We calculate separate star ratings for both laminate and floorboards. A five-star rating for both means the vacuum has sucked up the majority of the dust, while a one-star vac will leave a significant amount of dust behind, or failed to lift it out of crevices at all. There’s also a separate star rating for large debris – if it’s rated five stars, it sucks up close to 100% of the rice and lentils we spill.
Cleaning with a full dust container: Does the suction drop?
Suction can drop when a vacuum cleaner's bag or container is full of dust – we found one vacuum that loses suction by 91% when partially full, and another that only loses 1%.
To assess whether a vacuum loses suction, we use a clamp on a bagged model to simulate it being 60% full. With a bagless vac, we'll fill the container 60% full of dust.
We then test the vacuum's ability to suck out dirt from crevices on hard floors when there's just 40% capacity left in the dust container. We evaluate performance across different power settings, doing two runs on each power setting to ensure consistent results.
We found that a cordless vac loses suction by around 20% on average.
What separates a good result from a poor one?
A five-star cordless vacuum will show minimal differences in cleaning performance between a full and empty dust container. A one-star model will fail to suck up dust when the container is full, meaning your rooms fail to get a deep clean unless you empty it regularly.
Allergen retention: How well does the filter trap allergens?
Vacuuming can stir up dust particles, making them easier to inhale, so we check how well vacuum filters trap the tiny particles they suck up inside the chamber. These tests are very expensive to perform, and aren't something you'll find in other reviews.
Our lab technicians perform these tests inside a sealed chamber, where dust particles are introduced to the vacuum. Using air sensors, our experts measure how many particles are emitted back into the atmosphere after being vacuumed up.
The air sensors enables us to measure microscopic particles of dust (between 0.1 and 0.3 microns) which are invisible to the human eye, but could cause sneezing or trigger dust allergies or hay fever.
Large particles are easily blocked by the filter, and particles smaller than 0.1 μm are light and move chaotically, which makes them easy to capture. That’s why our tests focus on ultra fine particles in the 0.1 to 0.3 μm range, which filters generally struggle to trap.
What separates a good result from a poor one?
A five-star vac keeps 99.999% of the fine dust and allergens locked tightly within the container. And while a 99% filtration rate also sounds impressive, it lets one in every 100 particles escape. So it releases 1,000 times more dust back into your room compared with a filter that traps 99.999% of allergens. A vacuum that’s rated three stars or above for allergen retention does a pretty good job.
Ease of use: Is the vac easy to manoeuvre and handle?
We instruct an independent panel of consultants to check how easy it is to use each vacuum cleaner on tricky areas such as the stairs and at height, as well as handling and maintenance.
Our panel rates how smooth and easy it is to vacuum on Wilton carpet, hard floors, stairs, upholstery and uneven surfaces, making a note of how heavy the vacuum feels, whether it's uncomfortable to hold.
They also assess how easy it is to clean a car with it, and vacuum in hard-to-reach places above shoulder height – such as high shelves or around coving and cornicing.
Other checks include maintenance, handling and controls, including how easy is it to assemble and dismantle the vac for storing, empty the dust container, and replace and clean the filters, change any attachments and read the instructions; as well as what the grip of the handle feels like and how easy it is to use all the switches.
We test how difficult each vacuum is to push and pull. Some cordless vacuums take as much as 72 Newtons of force – the equivalent of lifting more than 7kg.
Our ease-of use assessments generate a rating from one to five stars – with one being poor and five being good – for each of the following tests:
- Maintenance
- Versatility
- Vacuuming at height
- Handling and controls
- Cleaning stairs
- Vacuuming on upholstery
- Vacuuming on carpet
- Vacuuming on hard floor
- Vacuuming on uneven surfaces
If you don't have time to contemplate each star rating individually, we also give an overall star rating out of five for ease of use.
What separates a good result from a poor one?
Most vacuums lose marks because it’s difficult and messy to change the filters or dust container. A five-star vac will score well across all of our tests, offering excellent manoeuvrability across different floor types, simple maintenance and good handling on stairs or at height.
Battery life: How long does the battery last?
We measure how long each cordless vacuum can run for on both the maximum and minimum settings, testing across the entire power spectrum to make sure battery life is accurate.
There are huge differences in run time between the best and worst models. Too many vacs are dead inside of 10 minutes of full power cleaning. Or, they will clean for a long time on the low power setting, but do a terrible job.
We not only test battery life on low power, used solely on hard floors, we also test each model's running time on its most powerful setting while cleaning carpet.
For each tested model, you'll find star ratings, specifications and contextual analysis for each of the below:
- Battery life overall
- Maximum power battery life
- Minimum power battery life
- Cleaning on minimum power
- Battery recharging
Lithium-ion batteries always deplete and eventually die over time, and at Which? we believe that cordless products should last longer than the batteries they come with. That's why we no longer award Best Buys if it's not possible to buy spare batteries from the manufacturer – no matter how good the vac might be.
What separates a good result from a poor one?
A good model may last more than 20 minutes on maximum power, while a poor one may lose battery in less than 10 minutes, making it difficult to give your home a deep clean.
Battery life on minimum power tends to be longer across all models, with good models lasting over an hour, while poorer models conk out at around 20 minutes. Cleaning ability on minimum power is also important – it's no good having a long running time if it doesn't pick anything up, so don't settle for less than three stars overall.
Noise: Does it make a racket while running?
Lab technicians use a multi-channel noise measurement system in a reverberation room to accurately assess the noise level of each cordless vacuum.
The tests are run separately on hard floors and carpet, using the appropriate floorhead, push force and power setting. We record the sound level in decibels, and make a note of any disturbances or unusual noises, such as whistling or squeaking while it’s running.
The noisiest vacuum we’ve tested is around four times louder than our quietest vac.
What separates a good result from a poor one?
Four or five star vacs are quieter than most, and you should be able to conduct a conversation while using them. One-star vacs make a real racket – one of the noisiest vacuums we’ve tested is as noisy as a hairdryer or blender.
Energy consumption: Does the vacuum use too much energy?
We conduct three separate tests to measure the cordless vac’s energy consumption.
First our lab technician measures how much energy the vac consumes while charging, followed by how much energy is consumed when it’s plugged in but already fully charged – this is known as trickle charging. We also consider how long the battery lasts while cleaning.
We can then work out how much energy is used to vacuum a 10m² space, and in turn, calculate the star rating.
What separates a good result from a poor one?
A lot of our cordless vacs are rated five stars for energy consumption, because they don’t tend to use too much energy compared to other appliances, such as dishwashers. This is why we don't give Eco Buy recommendations for cordless vacuum cleaners. Still, it’s good to know if a vacuum uses more energy than is necessary.
Which? members can filter all of our cordless vacuum cleaner reviews by how good it is at carpet cleaning, battery life, allergen retention, pet hair removal and more
How we calculate the scores
We update our test program each year to ensure it’s as relevant and as comprehensive as it can be. We speak to the Which? community and track market trends to discover what matters most when choosing a new cordless vacuum cleaner.
When calculating the score, we consider what’s most important. Which? members told us that, first and foremost, a vac needs to be good at picking up dirt off any surface and keeping it contained - that's why cleaning and allergen retention make up a large chunk of the overall score. Equally, a vacuum that is hard to use or doesn’t have enough battery to finish the job causes frustration. To be a top scorer, it needs to be the complete package.
The most important elements of the test carry more weighting than others when it comes to calculating the score. Here's how the weightings break down:
- Cleaning performance and allergen retention (60%)
- Ease of use (20%)
- Battery life (15%)
- Noise and energy consumption (5%)
How we choose the products
We test nearly 50 vacuums each year in our laboratory, which are hand selected by our market analyst.
We buy all of our own vacuums to test, spending around £16,500 per year, so that our reviews remain 100% impartial. We also ensure we test vacs that are suitable for different budgets – we assess premium models that cost more than £1,000 alongside budget options priced at around £100.
It’s important that we test vacuums that our members are interested in buying, regardless of what the manufacturers or retailers are pushing. I monitor new releases, market trends and consumer habits to ensure the products we’re choosing matter to our members. By covering a diverse range of brands and models, we can provide impartial recommendations to fit your budget.
Is it a Best Buy cordless vacuum cleaner? What our verdicts mean
Our recommendations will help you narrow down your shortlist, although you should still read our reviews to check for any weaknesses that might impact your buying decision.
Best Buy-recommended cordless vacuums
76% or more
Cordless vacuums that score 76% or more are Best Buy models that impressed us most in our tests and come with our firm recommendation.
Best Buy cordless vacuums typically excel where it really matters. They're easy to use, effective on different types of floors and keep the allergens locked inside the filters.
Great Value-recommended cordless vacuums
60% or more
How much buyers are willing to spend on a cordless vac varies, so that’s where our Great Value recommendation comes in.
These models do well in our tests – scoring 60% or more – while also being at least 20% cheaper than the average price of the cordless vacuums we’ve tested.
Great Value cordless vacuums are the ones to go for if you’re looking for a bargain. Some even score highly enough to be Best Buys as well.
Don't Buy cordless vacuums
45% or less
Cordless vacuums that score 45% or below are Don’t Buy models to avoid.
Don't Buy cordless vacuums typically fall down in some crucial areas. They might be difficult to use, have terrible filters or perform poorly during hard floor and carpet cleaning assessments.
To discover our Best Buy, Don't Buy and Great Value recommendations, head to our cordless vacuum cleaner reviews and use the filters
Our cordless vacuum experts
Alongside our lab experts, a team of in-house specialists coordinate our test projects and ensure our reviews are as helpful and informative as possible. Here's the team behind it all:
- Humairaa Habib, senior researcher & writer: Analyses a technical lab report to get key insights into cordless vacuum cleaner results, and translates data into relevant and helpful reviews for our members. She ensures content is easy to digest and helps members make buying decisions, while fact-checking manufacturers’ claims against our own data-backed evidence.
- Victoria Purcell, home editor: Victoria keeps a close eye on what's trending in the floor cleaning space to make sure we’re answering the questions that matter to you. She picks up on patterns in our reviews, consumer pain points and social media hype to help focus our news and advice so that you can make informed decisions.
- Monika Gil, senior scientific advisor: Monika turns hundreds of data points from our laboratory into simple-to-understand scores and star ratings. She’s got her eye on the ball for all things lab-related, and ensures our test program remains comprehensive. You may also see her contributing her expertise to our vacuum cleaner content.
- Finn Rainbird, market analyst: Finn knows the cordless vacuum cleaner market inside-out, keeping the rest of the team up to date with the latest news and releases, and working with the laboratory to shortlist products for testing. From household brands to newcomers, he ensures we’re testing the cordless vacuums that you’re interested in.