How we test cordless vacuums

Covering everything from how effectively they clean to how much of a racket they make, we've independently tested a range of big-brand cordless vacuum cleaners so you can be sure the one you're buying lives up to its claims.

Our reviews answer the most crucial questions about cordless vacuums, from how well it cleans, to how long the battery lasts, and how noisy it is.

Find out which models nailed our tough tests in our guide to the best cordless vacuum cleaners

Why our cordless vacuum cleaner tests are different

Many free-to-access websites review cordless vacuum cleaners using an individual tester to generate scores based on that individual's preferences, or a small number of cursory cleaning tests.

We strap every vac into our custom-built rig to test it under lab conditions on both carpet and laminate floors.

We use fine Arizona sand and comb real cat and dog hair combed into Wilton carpet to test how long it takes each vac to pick it up. With the latter, we found one that took more than three minutes, while the best took just 42 seconds.

Our assessments reveal which models lose suction as the battery power decreases, too. We run the vacuum cleaners on full power and when the battery is only 20% charged.  

We also check how well vacuum filters trap the tiny particles they suck up – these are very expensive to perform, and aren't something you'll find in other online reviews.

And finally, an independent panel conducts our ease of use tests.

What are Which? Best Buy, Great Value and Don't Buy cordless vacuums?

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 cordless vacuums

Cordless vacuums that score 76% or more are Best Buys and come with our firm overall 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.

Don't Buy cordless vacuums

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.

Great Value cordless vacuums

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 pretty 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 Great Value models also score highly enough to be Best Buys.

To discover our Best Buy, Don't Buy and Great Value recommendations, head to our cordless vacuum cleaner reviews and use the filters

How is the Which? score calculated? 

Because we know what matters most to you, some elements are more important than others, so carry different weights:

• 75% suction, filtration and battery life
• 20% ease of use
• 5% noise levels

Below are the key testing categories and how we evaluate each one.

Cordless vacuum suction, filtration and battery life

How clean will the cordless vac leave my floors?

We test the suction of each cordless model on three different surfaces – laminate, floorboards and carpet – so you know whether it will work well in your home.

Using 25g of dust for each vac, we carry out two runs on each surface type, seeing how much of the dust is in the canister at the end.

We also look at the tools it comes with, such as nozzles, to see if they're effective at picking up dust.

How long will the cordless vac battery last? 

Although cordless vacs have unshackled us from the power cable, that has come at a cost – battery life. 

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 at low power setting, but do a terrible job. 

To measure battery life, we time how long each cordless vacuum takes to charge and how long it can run for. Many manufacturers base their running time claims on using the cordless vacuum on the standard setting. 

We not only test batteries on low setting, used solely on hard floor, we also make sure that we test each model's running time on its most powerful setting while cleaning carpet. 

We also check how well the vacuum cleans when only 20% of its charge remains. The best machines will maintain excellent pick-up under these conditions, but some pick up much less when the battery begins to run down.

If a model doesn't get at least three stars in our overall battery life rating, it can't be a Best Buy. We also prominently flag the models that give excellent cleaning AND long runtime in our reviews. 

For each tested model, you'll find in-depth star ratings and specification information detailing minimum and maximum power runtime, how well they clean on low power and how speedily the battery recharges. 

Can the cordless vac battery be replaced?

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 also no longer give cordless vacuum cleaners Best Buy recommendations if it's not possible to buy spare batteries from the manufacturer – no matter how good the vac might be.

Cordless vacuum ease of use

A vacuum cleaner is no good if it's a pain to use, empty and manoeuvre, so we put each model through a range of ease-of-use tests assessed by an independent panel. We get panel members to rate how smooth and easy it is to vacuum on Wilton carpet, hard floors, stairs, upholstery and uneven surfaces, making a note of how heavy it feels, whether it's uncomfortable to hold and how easy it is to push and turn.

We also ask them to assess how easy it is to take each vacuum out to clean a car, and to vacuum in hard-to-reach places above shoulder height.

If that wasn't enough, we also get them to assess how easy each vac is to assemble and dismantle for storing; what the grip of the handle feels like; how easy it is to empty the canister, change any attachments and read the instructions; as well as what it's like using all the switches.

Cordless vacuum noise levels

You won't be able to tell in the shop just how noisy a model is – that's why we test the sound of each vacuum cleaner in a chamber in our lab. 

The worst get up to 88 decibels, which is the same as the noise from a busy road.