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How we test vacuum cleaners

By Matthew Knight

Learn more about how we test vacuum cleaners for our vacuum cleaner reviews.

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

From Dyson to Miele, and Bosch to Hoover, we've tested the latest vacuum cleaners to find out which are really worth their price tag - and which you shouldn't waste your money on. 

Through our independent lab tests, we've uncovered vacuum cleaners that pick up only 30% of the fine dust we challenge them to suck up, while a Best Buy can vacuum up to an impressive 90%.

Our vacuum cleaner video guide above reveals just how far we go to find the best vacuums. You'll also see how big a difference a Best Buy vacuum cleaner can make to your home compared with poorer-scoring models.

Head to our vacuum reviews to find out which models come top, and which ones will be a waste of your money.

Each review is based on the results of our independent lab tests, which are designed to answer all your key vacuum cleaner questions:

  • How well will the vacuum clean fine dust and dirt from my floors?
  • How well will it clean large debris from my floors?
  • Can the vacuum keep dust and allergens locked inside?
  • Is it able to maintain suction power while the bag or canister fills up?
  • How quickly does the vacuum cleaner pick up pet hair and longer hair?
  • How easy will it be to use and manoeuvre?
  • Should I buy it?

Only the models that score well in each of these areas of our tests earn a place among our recommended Best Buy vacuums.

How well will it clean dust and dirt from my floors?

You can't tell in the shop how well a vacuum actually cleans, which is where our expert tests come in. When testing vacuum cleaners, we let machines do the hard work by attaching them to custom-built test rigs and setting them to work on dust and grime.

For our carpet test, a machine spreads super-fine dust over a carpet and grinds it in. We then strap each vacuum cleaner into the rig, which pulls and pushes it back and forth five times as it sucks up the dust.  

Each vacuum cleaner covers a distance of 288m in this test alone. The rig springs into action again to do a similar job for smooth and creviced wood floors.

288mThe distance a vacuum cleaner covers in our fine dust tests

 

A bad vacuum cleaner picks up less than half of the dirt in the carpet, whereas a Best Buy can pick up twice as much.

We conduct the same fine dust pick-up test on carpets, flat laminate floors and also crevices to simulate the gaps you find between floorboards. 

But it's not just fine dust that you'll need to clean up at home, which is why we also challenge each vacuum to pick up larger debris. We use a large amount of dry rice, spilled onto a flat laminate floor, to represent larger bits of dirt and spills in the home, and measure how much each vacuum cleaner can suck up. Some vacuum cleaners will just plough larger debris around in front of them rather than sucking it all into the machine.

Is it able to maintain suction power while the bag or canister fills up?

Our tests have found that suction power can drop off by more than 30% as the vacuum cleaner fills up. 

A powerful vacuum cleaner is no good if its suction diminishes as it gets full. To test this, we set each vacuum to work on our rig again, measuring the suction when bags or canisters are empty, and again when they're filled with dust and debris.

Can the vacuum cleaner keep dust and allergens locked inside?

Many vacuum cleaners leak out some of the fine dust they suck up and leave a dusty residue behind, which can exacerbate symptoms for allergy sufferers. To uncover the models that keep fine dust safely locked away inside, we use specialist machinery to test how much dust and fine particles the vacuum cleaners retain.

How quickly does the vacuum cleaner pick up pet hair and longer hair?

To assess each vacuum cleaner's pet hair pick-up, we comb real cat and dog fur into an area of carpet and then time how long each vacuum cleaner takes to pick it up. Poor-scoring models can take more than three minutes, while the best clear it in less than 30 seconds. 

30 seconds - the time it takes a good vacuum cleaner to clean up a big patch of entangled pet hair.

But pets aren't the only culprits when it comes to moulting, as anyone who has ever had to untangle a vacuum brush bar can attest to. That's why, for our longer hair test, we use real human hair (from a salon), distributing it on carpet to reflect a typical home environment. We then rate how speedily each vacuum can suck them all up.

If that wasn't enough, we also test how long it takes each vacuum cleaner to remove fluff from a cushion using the provided upholstery tool.

How easy will it be to use and manoeuvre?

A great vacuum cleaner is no good if it's a pain to use. This is why we ask a panel of experts to assess just how easy each machine is to use in common scenarios, from vacuuming up and down stairs to moving it across different and uneven surfaces. They also check how easy it is to change and use the attachments and to empty the bag or canister. 

In 2016 we also started testing the push and pull force of vacuum cleaners. We have tested vacuum cleaners that are as difficult to push as picking up an Olympic standard shot-put!

Some vacuum cleaners are unwieldy, can't easily get into awkward spaces and are heavy, while others are light to manoeuvre on a range of surfaces and around furniture, and have easy-to-use attachments. We award a star rating to each vacuum for ease of use, based on these scenarios.

We also pass judgement on how easy the vacuum cleaner is to maintain, such as the ease of regularly cleaning hair from brush bars and also how easy it is to clean and replace the bags, containers and filters.

Is the vacuum cleaner irritatingly noisy?

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. We've found noise levels vary dramatically, from 65 up to 90 decibels - that's the difference between the sound of conversation a metre away to the sound of a busy main road.

We also ask a panel of experts to rate the noise of each vacuum cleaner and penalise models that make an annoying rattling or other irritating sound.

 

65 - 90 decibelsThe difference in noise levels recorded from vacuum cleaners

73% - the score a vacuum cleaner needs to be a Best Buy.

Should I buy it?

Each of the assessments described above goes part way to making up a total test score, which is the percentage figure awarded to each vacuum. Certain assessments are more important than others and so carry different weights:

  • 75% cleaning and filtration
  • 20% ease of use
  • 5% noise and energy use

A vacuum cleaner needs to score 73% in our tests to earn our Best Buy recommendation. Vacuum cleaners that score 40% or less are highlighted as Don't Buy models to avoid.

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