Best Air Purifier 2021: Clear the air and ease your allergies with the top purifiers from £99.99

The best air purifiers can help to ease the symptoms of asthma, hayfever or other allergies by cleaning the air in your home, removing pollutants and irritants such as pollen, dust, pet dander and smoke. With good-quality air purifiers available from £100 to well over £1,000, there are plenty of great choices for every budget.

But with machines ranging from downright useless to ultra-effective, it’s essential you do your homework before you choose which one to buy. To help out, we’ve tested a selection of machines to pick out the best air purifiers you can buy – that is, the ones that quickly and efficiently clear the air and are easy to both set up and use. Not sure what to look out for? Have a read of our buying guide below, where we’ve summed up the key factors you need to consider before parting with your hard-earned dosh.

Alternatively, feel free to skip ahead to one of the following sections:

Editor’s picks

How to choose the best air purifier for you

How much do I need to spend?

Air purifiers can cost as little as £100 or well over £1,000, but it’s not simply a case of the more you spend, the better the machine. Indeed, we found the Bionaire Air Purifier, which retails at under £160, has features that are usually only found in much more expensive machines. But that’s not to say that a pricy air purifier is inevitably overpriced, with the Blue Air Pro L providing a high-tech way of easing allergy symptoms for larger areas. Also remember it’s not just the initial financial outlay you need to think about, with operational costs ranging from a few pounds a year up to over £70 per annum.

How do air purifiers actually clean the air?

Air purifiers use different kinds of filters to do their job – usually, a large washable, reusable pre-filter to collect the large particles, plus a finer filter, which is usually a disposable high-efficiency particulate air (HEPA) filter. The length of time this lasts varies, but on average expect it to need replacing every six months (or fewer if you use the machine less). It’s the HEPA filter that catches all the tiny airborne nasties, and these are capable of catching particles as small as 0.3 microns – which is more than three times smaller than a cigarette smoke particle.

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What is the Clean Air Delivery Rate (CADR)?

The CADR aims to provide an objective measure of the effectiveness of a portable air purifier at dealing with different types of allergen. A purifier with a score of 250 for dust particles is as effective as adding 250 cubic feet of clean air per minute. Buyers should focus on the results of the specific pollutant they’re aiming to eradicate, whether that’s pollen, smoke or dust, and many manufacturers will supply CADR figures for the most common.

Generally speaking, the higher the CADR, the larger the room it can purify effectively. It’s also worth comparing manufacturer figures for the maximum size of room as these can vary enormously, sometimes when the CADR does not.

Can air purifiers help protect against viruses?

Understandably, there has been a lot of talk over the last year around whether HEPA air purifiers offer any protection against viruses, including the Coronavirus. The answer is pretty complex. Most viruses – and the droplets of mucus and saliva that might contain them – are perfectly capable of filtering particles in the 20 to 500 nanometre range in which you’d find most viruses, including Sars-Cov-2. What’s more, the US Centre for Disease Control has advised that, used properly, air purifiers can help reduce airborne contaminants, including viruses, in a home or confined space.

However, there’s no way to ensure that a HEPA air purifier would catch the virus prior to you inhaling it, and there are a lot of variables in play, including the type of filter used, the size of the room and the airflow in it. There’s also still a lot of discussion about the extent to which many viruses are spread through the air or transmitted through contact with respiratory droplets. In short, an air purifier might help, but there’s not enough evidence to make the case compelling.

What other factors should I consider?

  • Filtration performance should be your priority. Your symptoms will only be eased to a noticeable extent with an air purifier that works quickly to clean the air.
  • Noise is another factor – you don’t want to replace one irritation (allergies) with another (the sound of a jet plane in your room). For many, the hum is something that doesn’t bother them, but some purifiers can get very noisy. It’s also worth remembering that, while some machines are quiet on their lowest setting (where they’re often at their least effective), they might be loud on the fastest (where they’re working at their best).
  • Speed settings. Most air purifiers have a choice of speeds so you can keep it lower for sleeping and turn it up when the pollen count is high. A night mode can also help if you want a quiet setting and dimmer lights while you sleep – although we found this doesn’t always work as well as you’d hope.
  • An air-quality sensor, which enables the machine to switch itself on when the air quality becomes poorer, can be useful. After all, you can’t see when the air quality dips, for example, as the result of a high pollen count.
  • A few high-end units double as humidifiers, managing the moisture in the air to prevent dry air causing irritation to the nose, throat, lips and skin.
  • What about a carry handle? These are handy if you need to move it from room to room. Wheels, a compact design and a low weight won’t go amiss here either.
  • Easy-to-use controls are always a plus, with a good remote control a must-have when you’re using a purifier in a larger room. Some purifiers are even packing in Wi-Fi connectivity and apps, so you can set the purifier going before you get home from the office or control it from your phone.
  • Filter replacement indicators aren’t crucial and not all air purifiers have them, but this is a helpful feature as a clogged air cleaner won’t work properly.
  • Should you consider getting a timer? If you want your machine to come on a few hours before you’ll be using the room, or if you want to be able to turn it off automatically, this is a good option.

The best air purifiers for small rooms

1. HoMedics Totalclean Air Purifier AP25: The best budget air purifier

Price: £99.99 | Buy now from Amazon

Hay fever sufferers and asthmatics, rejoice. This clears pollutants – especially cat and dog allergens, house dust mites and pollen – from the air at the kind of speed you’d expect from much more expensive machines. You don’t get all the bells and whistles you would with pricier machines (although you do get some, such as night mode, a timer and a filter indicator) and it’s quite loud on the fastest of the three speeds. But it’s endorsed by Allergy UK, looks smart, doesn’t take up too much room and is easy to move from room to room.

Key specs – CADR: Not stated; Max room size: 72m²; Power settings: 3; Dimensions (HWD): 54 x 53 x 29 cm; Weight: 5.33kg; Filter replacement indicator: Yes; Warranty: 2 years