Which? Best Buy air purifiers
Discover the best air purifiers. We reveal the best air purifiers that can be trusted to quickly and effectively clean the air in your home.
The best air purifiers clean the air in your home quickly, capturing polluting particles - such as dust, smoke and pollen. They needn’t cost a fortune. We’ve found one of the best air purifiers we’ve tested costs £350 less than some other machines on test.
The best air purifiers will also clean without making too much noise, which is really important if you want your air purifier to be cleaning the air while you sleep.
Buy the wrong air purifier, and you’ll notice little or no difference in the quality of the air in your home. The air purifier simply won’t be powerful enough to quickly and effectively remove pollutants, such as pollen, dust, smoke and pet dander, from the air.
In fact, one of the air purifiers we’ve tested was so poor at capturing pollutants that it is a Don’t Buy. It was 26 times worse at removing dust from the atmosphere than the best air purifier we tested. This means you’d need to leave your purifier on for much, much longer to have the same effect in your home as one of our best air purifiers. Plus many of the polluting particles would remain in the atmosphere, rather than being removed.
We rigorously assess each air purifier we review in the Which? test lab. Only the very best air purifiers that capture the most pollutants and clean the air the quickest become Best Buys.
- We test each air purifier’s ability to extract particles of dust, smoke and pollen from the atmosphere inside our specially-built test chamber.
- The best air purifiers will remove more than 90% of the particles we add to the chamber during our tests; poor machines can only manage 44%. The worst remove so few that we can’t officially report on the figure.
- We test how quickly each air purifier cleans the air, how easy they are to use and we estimate the room size that each would be most effective in. The best air purifiers will work effectively in large rooms in your home, the worst will only be successful in spaces the size of a single-wardrobe.
How we uncover the best air purifiers
No one tests air purifiers as thoroughly as we do at Which?. You can be sure that a Best Buy air purifier will remove allergens and pollutants from the air in your home quickly and effectively. The worst work too slowly and don’t capture enough polluting particles.
- Clean-air delivery rate: we use pollen, smoke and dust to measure the clean-air delivery rate (CADR) of each machine. This measures the reduction of particles in the air.
- Particle removal: we calculate the percentage of particles removed by the air purifiers and compare this with the particles that are naturally removed from the air with the machines switched off.
- Noise: we measure how loud each machine is on its lowest and highest settings. Our expert panel then listens for any irritating noises made. This means that we can let you know whether a quiet machine also makes an annoying rattle that would prove hard to live with in your home.
- Energy: We record how much electricity each air purifier uses and then calculate how much this would cost if you ran the machine for 12 hours a day for a year. The best air purifiers won’t be the cheapest machines to run, so don’t make a buying decision based on running costs alone.
- Ease of use: we check how easy it is to set the machines up, use them and remove and replace the filters. The best air purifiers have easy-to-remove filters and are a doddle to set. The worst are harder to use, and filter removal and replacement is a struggle.
- Smart air purifiers: we connect the purifiers to their apps and see how easy each is to use from a smartphone and check whether all of the purifiers’ functions are available from the app. Our tests found that some apps were noticeably easier to use than others.
Air purifier reviews you can trust
We test air purifiers from big names such as Bionaire, Blueair, Dyson, DeLonghi, Electrolux, Homedics, Meaco, Philips and Vax. The brands that sit at the top and the bottom of our results table might surprise you. So, before you buy on name alone, make sure you look at our in-depth reviews.
Which? is independent. We work for you, the consumer, so you can be sure that our product recommendations are influenced only by our test results. We don't take advertising and we buy all the products that we test ourselves, so our advice helps you to make the right choice first time and avoid costly mistakes.
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