Dyson Purifier Hot + Cool Formaldehyde review

Beautifully designed, this oscillating fan heater purifies air and cools or warms your space as required — but is it worth the considerable cost?

Dyson Purifier Hot + Cool Formaldehyde review
(Image: © Joanne Lewsley)

Live Science Verdict

Already a design classic, the Dyson Purifier Hot + Cool Formaldehyde does a brilliant job at removing harmful airborne particles. However, it requires very deep pockets, and some buyers may be disappointed by its cooling function.


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    Stylish, functional design

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    Great at removing harmful particles

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    Multifunctional use


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    Very expensive

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    Can be noisy at high speeds

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    Not as cool as you think

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The Dyson Purifier Hot + Cool Formaldehyde is the latest purifier from the British technology giant. It removes harmful airborne particles, warms or cools a room as needed, and even destroys formaldehyde — a harmful, flammable gas often found in tobacco smoke, traffic emissions and fumes from wood fires. Equipped with a HEPA H13 filter and an activated carbon filter, the Dyson Purifier Hot + Cool Formaldehyde promises to remove 99.95% of particles as small as 0.1 microns.

Having already tested the Dyson Purifier Cool, we were excited to see the new features and functionality of the company's latest air purifier. The design certainly doesn't disappoint — this elegant, sophisticated air purifier is worthy of any stylish home. It also features a tilting mechanism and 350-degree oscillation, and can be controlled via the Dyson app or remotely.

Key Specs

Dimensions: H 30 in, W 8.6 in, D 8.6 in

Weight: 12.6 lbs

Filters: HEPA H13 filter, activated carbon filter and catalytic filter for formaldehyde

Max noise: 48 dB

Coverage: Up to 2,860 square feet

Modes: 10 fan speeds, auto mode, sleep mode, plus cooling and warming settings

Warranty: 2-year parts and labor

Energy Star Certified: No

The Dyson Purifier Hot + Cool Formaldehyde claims to provide a healthier, cleaner atmosphere in your home by removing pollen, dust, pet dander, mold and harmful odors from household chemicals. But did it manage to impress us during our review? Find out how we got on.

Dyson Purifier Hot + Cool Formaldehyde: How we tested

Our air particle monitor

The air particle monitor we use to analyse air quality. (Image credit: Joanne Lewsley)

We tested how well the Dyson Purifier Hot + Cool Formaldehyde could improve air quality in a 140-square-foot (13 square meter) bedroom. Using an air particle meter that detects tiny particles measuring 0.3 to 10 microns, we did a series of tests to measure changes in air quality.

First, we checked the baseline air quality in the room before turning on the purifier. We then ran the purifier on auto mode for 30 minutes and tested the particle levels again to see if there was an improvement. We did the same test using the purifier's highest fan setting to compare auto versus max speed performance.  

To challenge the purifier, we burned matches and incense cones to release more particles into the air. We measured particle counts before and after running the unit on auto mode to see how well it handled the pollution.

We also measured noise levels (decibels) on every fan setting, including sleep mode, and we looked at how easy it was to set up, use and maintain the Dyson air purifier.

Dyson Purifier Hot + Cool Formaldehyde: Features

Dyson Purifier Hot + Cool Formaldehyde

The LCD screen is bright, colorful and easy-to-read.  (Image credit: Joanne Lewsley)

The Dyson purifier offers multiple features and functions compared to other air purifiers, even in this premium price range:

  • Purifies the whole room: It uses patented Air MultiplierTM technology to generate circulation power that can draw even distant pollutants into the machine, projecting purified air throughout the room.
  • Heats and cools as needed: It features an intelligent thermostat that turns the heat off when the desired temperature is reached, preventing wasted energy. 
  • Fully sealed to HEPA H13 standard: The filter meets the HEPA H13 standard, and the whole machine is fully sealed to the same standard, so no pollutants can bypass it.
  • Senses and reports air quality automatically: Integrated sensors constantly analyse air quality, while a unique algorithm cross-checks data every second, to diagnose pollutants and display live results on the LCD screen.
  • Captures gases and ultrafine particles: The HEPA H13 filter captures 99.95% of particles as small as 0.1 microns. An activated carbon layer also removes odours and gases, including VOCs (volatile organic compounds).
  • Destroys formaldehyde continuously: The Dyson catalytic filter continuously traps and breaks down formaldehyde molecules into water and carbon dioxide without needing replacement.
  • Oscillating 350-degree movement: The top of the unit moves through 350 degrees and can be tilted, optimising airflow around the room.
  • Remote control: A magnetised remote control can be attached to the top of the unit, so you don't have to go looking for it.
  • Dyson app: The app keeps track of air quality, air temperature and filter lifespan, while its scheduling functions allow to control the purifier from anywhere in the world.
  • Compatible with voice devices: Use compatible voice assistants like Alexa or Google Assistant to control your purifier with voice commands.

Dyson Purifier Hot + Cool Formaldehyde: Design

Dyson Purifier Hot + Cool Formaldehyde

Stylish and expensive-looking, the Dyson Purifier Hot + Cool Formaldehyde is compact enough to be a subtle addition to any room.   (Image credit: Joanne Lewsley)

There’s simply no denying it — this purifier is gorgeously designed. The Dyson Purifier Hot + Cool Formaldehyde is sleek and expensive-looking but compact enough to be a subtle and stylish addition to any room. 

Standing 30 inches (76 centimeters) tall with a base diameter of around 8 inches (20 cm), it’s much smaller in height and footprint than the Dyson Purifier Cool. You can tuck it away in a corner or have it on full display, plus it’s portable enough to move from room to room. 

This purifier features Dyson's signature bladeless fan design. It has an attractive white, bronze and gold color scheme that stands out from the usual "basic white appliance" look of most air purifiers. The smooth 350-degree oscillation plus tilt adjustment provides full room air circulation. 

Just above the perforated matte gold base is the power switch and LCD display. The displays shares live air quality data and fan speed. While you can't control the purifier (apart from switching it on and off) via the unit, a curved matte gold remote control is also provided, which magnetically attaches to the top of the fan when not in use — although this does tend to fall off occasionally.

The base houses the impressive filter system, with an easy-push latch to release the cover and allow access to the filters inside. The whole thing feels seamless, intuitive and impressively designed, even by Dyson's high standards.

Dyson Purifier Hot + Cool Formaldehyde: Performance

Dyson Purifier Hot + Cool Formaldehyde

The Dyson Purifier Hot + Cool Formaldehyde is less noisy than most air purifiers we have tested.  (Image credit: Joanne Lewsley)

We tested the Dyson purifier in a bedroom with the windows and doors shut. We began by checking how well it could improve ambient air quality. Using an air particle meter, we measured the particle levels before and after running the purifier for 30 minutes on the automatic fan setting. 

We were surprisingly disappointed with the results on the first test. At fan level 4, the Dyson purifier only achieved a 75.9% reduction in 0.3-micron particles and a 70% reduction in 2.5-micron particles. Ideally, we expect to see at least a 95% reduction in these small particles, and in fact Dyson claims its air purifier can remove 99.95% of particles as small as 0.1 microns. 

We ran the same test using the highest fan setting (fan level 10) and got only slightly better results — a 76.7% reduction in in 0.3-micron particles and an 85.7% reduction in 2.5-micron particles.

However, things looked up when we moved on to our incense test. We burned incense cones for 10 minutes in a room with the windows and doors closed. Burning incense releases larger particles into the air that can pose a risk to human health. The Dyson purifier achieved a very impressive 93.8% and 95.8% reduction in 2.5-micron and 10-micron particles at 30 minutes. 

For the match test, we burned 10 matches in a row in the room, releasing thousands of particles into the air. Again, the Dyson performed exceptionally well under these circumstances, eliminating 99.5% of 0.3-micron particles, 98.4% of 2.5-micron particles, and 100% of 10-micron particles in just half an hour.

It’s not uncommon to see air purifiers that struggle with improving ambient air do a great job removing particles released in the incense and match tests. However, we’ve tested quite a few air purifiers which seemed to sail through our testing with much better results, many of them far below the premium price of the Dyson. So overall, a mixed bag when it came to our testing.

During all our testing, however, we were impressed at how quiet the Dyson was during operation. Even at its most powerful fan setting it didn't clock in over 48 decibels, which is quieter than a normal conversation. At its quietest, it was barely discernible at just 24 dB, around the same as a whisper.

Dyson Purifier Hot + Cool Formaldehyde: The good

Dyson Purifier Hot + Cool Formaldehyde

The controls on the Dyson Purifier Hot + Cool Formaldehyde are easy to reach and operate. (Image credit: Joanne Lewsley)

We really like the Dyson purifier's stylish, compact shape that tucks nicely into corners without demanding a lot of real estate. The modern colour scheme of white, bronze and gold is classy and elegant, with a simple bladeless silhouette and gently sweeping oscillation.

Operation is also refreshingly intuitive between the easy-to-reach power button, the magnetized remote that attaches on top when not navigating settings, and connecting through a smartphone.

Dyson Purifier Hot + Cool Formaldehyde: The bad

It’s hard to find much to criticize about the Dyson Hot + Cool Formaldehyde. However, its high price tag — $849.99 at the time of writing — has to be mentioned. This is premium territory for air purifiers, and not many households will have deep enough pockets to fork out for such an expensive appliance. That said, the multifunctional fan for heating and cooling, plus the formaldehyde filter does mean you get an awful lot of bang for your buck.

As many buyers have commented on the Dyson site, the fan's cooling power leaves something to be desired. While it's not advertised as an air conditioning unit, the Hot + Cool element of the product name does suggest some control around the cooling temperature, which isn't present and could be misleading. So, if cooling your surroundings is an essential aspect for you, it might be better to swerve this purifier and buy an air conditioner instead. 

If we wanted to be super-fussy, the remote control could stay atop the unit more reliably with a better magnet, and 360-degree oscillation might be nice, but really these are very minor gripes. 

Dyson Purifier Hot + Cool Formaldehyde: User reviews

The Dyson Purifier Hot+Cool Formaldehyde gets rave reviews on the Dyson website, with an overall rating of 4.2 stars out of 5. Users praise its excellent purification technology and fast, even heating of rooms. They also love its sleek design, convenient app and voice controls. 

Quite a few users say it helps with asthma and allergies, especially at night, with one user remarking: "Bought [sic] to cope with allergies and blocked sinuses (post covid) that were making sleep a challenge. Finally get 6 to 8 hours sleep without waking up gasping for breath every hour."

Some users note that the purifier can be loud at high fan speeds and costly to operate, while quite a few say the fan lacks the cooling power they expected. One disgruntled owner complains it "doesn't cool. Seriously misleading." Another states, "It works fine as a heater, but it doesn't cool at all, it just blows unheated air around, which is really NOT the same as cooling."

Overall, most buyers are satisfied with the quality, design and features of the purifier, but beware if you’re buying this as a cooling fan, as users don't appear to agree with Dyson's claims on this issue. 

Should you buy the Dyson Purifier Hot + Cool Formaldehyde?

If you have deep pockets and prioritise beautiful design, then the Dyson Purifier Hot + Cool Formaldehyde could be perfect for your home. It's incredibly elegant, a talking point even, and it combines the functionality of a heater and a cooling fan with an air purifier, so could save you money in the long run.

However, we expected better results from our at-home testing to justify the higher spending. While the Dyson performed well in our incense and match tests, it was less than adequate in improving ambient air. 

If you live in a particularly smoggy area or one that's affected by smoke from wildfires, it could be a helpful appliance. But if you just want to improve the overall quality of air in your home, you may get a better result from a cheaper air purifier.

If this product isn't for you:

If you prioritize no-fuss functionality over stylish design, the Coway AP-1512HH is a stellar choice. It focuses purification power solely on fan speeds and a HEPA filter, and to save energy, its Eco mode automatically adjusts settings based on detected pollution. Ultimately, this unfussy workhorse delivers where it matters most — air quality.

If you're in the market for a stylish yet subtle air purifier, consider the Sensibo Pure. This budget-friendly air purifier features a modern, neutral design that seamlessly blends with home decor. Our at-home testing revealed impressive performance as well.

Or, if you prefer an air purifier that offers excellent value for money, the Levoit 400S air purifier is an affordable appliance that's easy to use and quietly efficient. From the intuitive app with its wide range of functionality to its stylish, sleek design, the Levoit 400S packs a lot for a mid-range purifier.

Joanne Lewsley

Joanne Lewsley is a UK-based freelance writer and editor, covering health and lifestyle news and features. She mainly creates evidence-based health and parenting content and has worked with a number of global sites, including BabyCentre UK, Medical News Today, Fit & Well, Top Ten Reviews, and Yahoo!