ir purification is a science and the technology behind it is as complex as it is misunderstood. Between unsubstantiated claims, misinformation and downright bogus marketing ploys from manufacturers as well as retailers, it’s no wonder a quick Google search for best air purifier yields so many varying results.

This undoubtedly makes the buying process a frustrating task and puts the consumer at risk for overspending on a device that is tantamount to a basic fan.

Clean air is an invisible benefit, unlike the obviousness of a cast on a broken limb, or the immediate relief of a cool fan on a hot day. But when a gain (clean air) is not visually obvious the product itself can become easy to exploit and difficult to navigate. Welcome to the world of air purifiers…

Before you purchase any air purifier it’s important to understand the vocabulary around the technology in order to understand what makes one machine better compared to another.

Let’s start with one of the most recognisable terms in the industry: the HEPA filter.

What is a HEPA filter?

HEPA stands for High Efficiency Particulate Air. A true HEPA filter will be disposable and superior to any rinse and replace type. It will need to be replaced anywhere from six months to two years depending on how often you use the machine and at what capacity.

What is PM?

PM stands for particulate matter. The term refers to a mixture of microscopic solid particles as well as liquid droplets found in the air.

The source of PM varies from dust, dirt, pollen, soot and hundreds of other invisible chemicals that are actually the result of other chemical reactions from larger pollution sources like factories, cars and industrial building.

How are people misled about HEPA filters and PM?

HEPA technology has become the industry standard for PM filtration so naturally many manufacturers saw the potential early on to use the term as a marketing buzz word rather than true science.

What most HEPA-based air purifier manufacturers forget to tell you is that their air purifiers are nowhere near the level of a medical grade HEPA filter—nor would they present the benefits of one.

Consumers are also chronically misled about the level of efficiency an air purifier can actually provide in regards to removing pollutants.

One of the more common claims you may recognise is the one that purports to “remove 99 per cent of all indoor allergens” but this is simply not true and refers mostly to the theoretical efficiency rating of the filter paper that is used in the air cleaning device but not the system as a whole. Clever, eh?

But be warned, a HEPA-based air purifier and one that uses a professional HEPA filter system are different products wrapped in a similar package.

For a filter to be considered a true HEPA filter, it must be certified to remove 99.97 per cent of all microscopic particles as tiny as 0.3 microns in size. For example, mould spores are between 10-30 microns and a human hair is between 40-300. There are significant differences in HEPA filters that will vary from brand to brand, and everything from the density and quality of the paper used in the filter, to how the filter is constructed within the machine will determine its efficiency.

So which one is the best of the best?

The Best Air Purifies 2021

IQAir HealthPro 250

Simply put the IQAir is the best air purifier you can buy. Not only is it relied upon in hospitals and schools, but the Swiss company has been making air purifiers since 1963 when they introduced the world’s first ever residential air filter to combat the indoor air pollution from coal ovens used extensively at the time.

This is not a history lesson but an indication that the technology created by IQAir has been meticulously tested and methodically developed for over 50 years.

This is an important point to consider as more and more recognisable brand names start to produce air purifiers with very little experience based in established scientific practices.

If a company that normally manufactures hair dryers and hoovers suddenly starts manufacturing air purifiers, regardless of the brand name you should be weary. Air purification is a very particular science and just because someone makes a phenomenal tech-driven device doesn’t mean you should trust it when they turn their hand to air purifiers.

At a glance: what makes IQAir the best air purifier?

HyperHEPA Filter

The IQAir uses a superior filter system. The highly regarded HyperHEPA as been tested and certified to have a filtration efficiency of 99.95 per cent for all particulate pollution down to 0.3 microns.

No leakage

This is a very important point: the IQAir filter system is 100 per cent sealed in the filter frame. Lesser quality air purifiers will experience leakage between the pleated HEPA filter pack and the frame.

While some units may actually use a higher grade HEPA, if the filter system contains a leak you are not gaining the real benefits of a quality air purifier—you’re just running a fan with a fancy HEPA filter in it.

An unsurpassed Air Flow system

The IQAir uses a bottom-to-top air flow that is unlike other devices. Designed with an intake air vent at the bottom, it pulls the polluted air through the multistage air filter system before releasing it into the room in a 320 degree air delivery. This specialised construction is called EvenFlow Diffuser technology, and it guarantees that the air filtration process is evenly distributed in all directions.

In fact, air flow is incredibly important in understanding and improving indoor air quality. There is a common misconception that sealing the home like a piece of Tupperware is how you achieve the cleanest possible air, when in truth this would actually cause more harm than good.

Where can you buy the IQAir?

While it may be temping to head over to Amazon and scour for deals, the IQAir only has one official UK supplier: Allergy Cosmos. As the name would suggest, Allergy Cosmos is a vast universe dealing in all things clean air and healthy life related. They sell other machines too, but the the IQAir range is only sold by them.

If you are serious about buying a proper, medical grade air purifier you should consider who are buying it from and how much they actually know about what they are selling. If a sales person repeats a bullet point list verbatim, they have most likely memorised the information rather than being properly trained to understand it. Allergy Cosmos are at the other end of this spectrum and will offer sincere, expert advice.

I tested this machine for one month alongside the IQAir air quality monitor and while it’s difficult to say that I personally felt any different, my home certainly did. Watching the numbers plunge from the danger zone levels of contamination to healthy clean air is equally startling as it is satisfying.

If you really want the best air purifier possible, then it can only be from IQAir.

Blueair Classic 405

Sitting very close to the top of the list is the supremely effective Blueair Classic 405. A well respected machine in the clean air community, the Blueair 405 can maintain a purified atmosphere in rooms of up to 434 square feet. What’s even more impressive is that it barely exceeds a low hum thanks to the HEPASilent technology.

This is the combination of a high quality true HEPA filter as well as electrostatic filtration, which not only offers an incredible performance but does so at a whisper.

With just three buttons to press on the machine itself, some of the Classic 405’s settings can be controlled only through the Blueair Friend app – so do check that your phone is compatible before purchasing.

Besides the basic fan speed function that can also be controlled on the machine, the app enables you to trigger a quieter Night mode, set a Child lock, adjust the LED intensity and link up with an external Bleuair Aware air quality sensor (sold separately) to automatically match its fan setting to your air quality.

This is a very well trusted brand for its quality components, long guarantee and sincere results. I personally owned this machine many years ago while living above a restaurant on Sunset Blvd. in east Los Angeles and can attest to its trustworthiness—if it can dispel the smog and chicken-scented dilapidation of my former abode it can handle anything.

As an industry standard, this is one of the best machines you can buy.

Philips AC2889 Series 2000i

A budget air purifier is a bit of a contradiction—any quality device intended to clean the air of an entire room will be at least a few hundred pounds, otherwise you really are just buying an expensive fan.

That being said, the Philips AC2889 is the best value, highest quality air purifier priced under £400. It includes a pre-filter and True HEPA filter, capturing up to 99 per cent of particles as small as 0.3 microns

Leave this air purifier on Auto mode and it will auto-detect your air quality, switching between fan-speed settings whenever it detects a significant change.

In our tests, this worked with such precision that the air quality reading leapt up when we started moving old furniture around in another room. When the purifier’s in-built sensor noticed an increased level of dust in the air, it kicked up a gear to combat the new pollutant.

This is a really neat-looking, impressively quiet air purifier with an approachable, user-friendly display. The air quality light on the front glows blue, blue-violet, blue-purple or red to give you an at-a-glance indication of the air quality in your room. It’s also app-connected – so you can use your smartphone to change settings and review your air quality.

Boneco P500 Air Purifier

The p500 air purifier is a beautifully built machine and sleekly designed compared to its competitors.

Remove the magnetically attached front panel and you’ll note the filter itself is remarkably large relative to the machine’s size, offering plenty of purifying potential.

But let’s be honest—this is not a medical grade machine and it’s a far cry from something like the IQAir or Blueair. BUT it will be useful to people who suffer from moderate allergies, own pets or want a good but not NHS quality air purifier.

A standout feature is the display brightness, which dims or brightens depending on the ambient light. You can either leave the machine in Auto mode, or operate it manually by cycling through the five available speeds with the press of a button.

A subtle and sophisticated presence in the room.

Blue Air Blue Pure 411

Here’s our runaway favourite choice for customers seeking simple, purification for smaller spaces. Supremely simple to use, it draws in air from all directions and only has one button (controlling its fan speed and power).

The Pure 411 weighs about half as much as a domestic cat – which means it’s fantastically portable, but perhaps also best kept away from inquisitive paws.

The fabric pre-filter around on the outside of the machine gives it a lovely, rich, matte look that’s a world removed from the stark aesthetic of the average purifier. And with an advertised minimum volume of 17 decibels, you have to be very close-by to hear it when it’s set to Low.


Based on the quality of the materials used, the particulars of the design and the proven technology within each individual component, anything from IQAir will be the best air purifier you can buy. There are few models that come close to this level of performance and none that reach it in quite the same way. Yes, it is expensive but the reason this Swiss made air purifier is priced higher than most is because it performs better, lasts longer and has 50 years of science backing up its claims.

As a more affordable option, and with an occasional discount offered on Amazon, the Philips AC2889 2000i.is your best bet. Blueair is the option to go for between these two in terms of price, although comparatively the Blueair Classic 405 is the superior machine. The P500 doll takes the style award but doesn’t skip the important bits inside—it’s not a medical grade machine but it will be suitable for certain homes with mild pollutants.