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- Exceptionally easy to setup and use
- Very quiet in operation
- Powerful fan should be a summertime boon
- Very, very expensive
- Extremely large
- Tiny remote control likely to get lost
Like a good many of its sister products, the Dyson Big+Quiet Formaldehyde is quite the design statement. In much the same way as some of Bowers & Wilkins’ flagship speakers, the huge gold and blue BP04 will definitely get your guests talking.
There’s no shying away from just how big this Dyson is, yet it backs this up with some mighty capabilities, including the ability to purify the air in a 100m2 room and to project air a full 10 metres.
But is that enough to justify its vast price tag, or earn it a place on our list of the best air purifiers? Let’s find out.
Dyson Big+Quiet Formaldehyde review: What do you get for the money?
Given the Dyson Big+Quiet Formaldehyde currently costs a heavyweight £900, you’d expect it to deliver quite a lot in return. Fortunately it does – although whether it’s truly worth the price will depend on the value you put on the design and the Dyson brand.
It’s a shame Dyson doesn’t quote a CADR rating, but the brand says its own measurements, carried out in a 100m2 space with 36 sensors, are superior to the industry standard 12m2/single sensor benchmark. As we’ll see, the BP04 packs a punch, but side-by-side spec comparisons are harder.
The Big+Quiet Formaldehyde monitors CO2 levels, temperature and humidity, and can capture PM2.5, PM10, volatile organic compounds, nitrogen dioxide (NO2). It destroys formaldehyde through three-stage filtration, comprising H13-grade HEPA, activated carbon and Selective Catalytic Oxidisation (SCO) filters. The HEPA filter can last up to 11 years, although Dyson recommends swapping it out after five years. On the other hand, the carbon filter has a two year lifespan – although the app will tell you when you really need to buy replacements. Neither are cheap, though, at £85 apiece.
Dyson claims it’ll capture 99.9% of particulates, remove dust, allergens, gases, odours, viruses and bacteria, reduce exposure to pollen, dander and mould spores.
READ NEXT: What are the benefits of air purifiers?
The Dyson Big+Quiet has a single button, alongside a small colour screen. The basic functions are operated with a small remote control, which magnetically attaches to the front of the unit, although all of these functions are mirrored on the slick Dyson smartphone app. Similarly, while it’s possible to view basic pollutant levels and a trend graph on the screen, more advanced displays are featured in the app.
Air passes through the cylindrical filters in the base of the unit, and clean air is expelled through a circular aperture at the top. There are ten fan speeds, plus automatic and nighttime modes. And unusually, it’s possible to tilt the angle of the fan through 0.25 and 50°, or select the breeze mode, which emits a less directional airflow.
As you might expect at this level, the Dyson has voice integration with Alexa, Google Home and Siri. It’s possible to set schedules and a continuous monitoring mode allows you track trends at 15 minute intervals over long periods of time.
Dyson Big+Quiet Formaldehyde review: How well does it work?
I’ve not encountered an air purifier that’s easier to set up; indeed, the biggest hassle was working out where to store its massive box. The head of the unit clips onto the base with a satisfying click. Plug the unit in, download the app and it will detect the presence of the air purifier to connect. All that needs to happen next is to input your Wi-Fi password, and you’re away.
The head of the unit detaches by sliding a release catch to the side, and to remove the filters you lift off the gold outer shell, lift out the HEPA filter and release the catches to remove the wraparound carbon filter. Again, the entire process could hardly be more simple. The instructions say it will perform best when placed 1m from the wall, with the unit facing along the longest wall. Helpfully, the 11.9kg unit is mounted on castors so you can wheel it out of the way when it’s not in use.
I like that there’s a single button to turn on the unit, and that you can grab the remote control from the front of the unit to start or stop the air purifier, adjust the fan speed and tilt, or activate automatic, night or scheduling modes. The remote control has a reassuring solidity to it, although I can’t help thinking it would be easy to knock off, or may be irresistible to children. It’s small enough to end up in the bottom of a toy box or down the back of the sofa.
To test the effectiveness of its purification functions, I sprayed a can of deodorant for five seconds, and used an air quality monitor to record the PM2.5 levels (measured in micrograms per cubic metre, or µg/m³). Most air purifiers lag behind the air quality monitor, but the Dyson was a step ahead in detecting the PM2.5 spike. Across a series of tests, it worked through the gears in automatic mode to clean the air quickly.
For more information on how we’ve put the Dyson Big+Quiet Formaldehyde through its paces, check out our article on how we test air purifiers.
It filtered air from 140.7µg/m³ to a safer 25µg/m³ in 139.5 seconds, which is among the faster units we’ve tested. In each of our tests, it filtered out the highest levels of pollutants quickly, although this slowed as the levels reduced, which is common.
The Dyson registered higher pollutant readings than our air quality meter, but the gap was consistent – so that’s no bad thing at all. And I like that the screen atop the unit shows a decreasing graph to show what it’s up to without having to use the app.
To get a truer picture of the speed at which it works, I selected the breeze mode rather than a more focused blast of air, which could have impacted our readings. But in regular use it would likely make little difference.
The fan itself is worthy of note, because in its fastest setting, we measured a maximum airspeed of 2.6m/s using an anemometer. That’s not far off your typical dedicated fan, although for context, the Dyson Cool CF1 pumps out air at up to 3.8m/s.
The Dyson Big+Quiet Formaldehyde certainly delivers on its “Big” billing. But it’s pretty good for its “Quiet” claims, too. I recorded a little-more-than-background 32dBA at its slowest fan speed and in night mode, rising to 43dBA at its midway point and 53dBA flat out. That last figure is particularly noteworthy, because the Big+Quiet can shift air up to ten meters at quite a rate. Big and quiet indeed.
It consumes 4.5W on its lowest setting and 32W at its highest. Again, those figures are at the lower end of the air purifiers we’ve tested, and particularly impressive given the Dyson’s output.
Dyson Big+Quiet Formaldehyde review: What could be improved?
The Dyson Big+Quiet Formaldehyde might be a premium product but crikey, it’s priced like one. Upscale pricing has long been the firm’s hallmark, but a cut in price – or even a de-specced version would certainly be welcome.
That said, when it comes to the product itself, there’s very little that could be improved.
I’d like to see a CADR rating, though. While Dyson has devised its own measures, it makes it hard to benchmark the Big+Quiet against its competitors in this regard.
Dyson Big+Quiet Formaldehyde review: Should I buy it?
If you have the budget, and place a strong emphasis on brand and design, then the Dyson Big+Quiet Formaldehyde is definitely worth shortlisting – particularly if you have large rooms, or enjoy open-plan living, where its ability to eliminate cooking smells could be a real draw.
That it filters and detects a huge range of pollutants is a given at this price, so it’s down to its ease of use – it’s as slick in operation as the very best Apple products and delightfully intuitive – to really stand apart.
It’s worth noting that of the other air purifiers we’ve tested, the Hoover H-Purifier 500 is smaller yet can handle slightly larger rooms, and the Blueair Signature is faster to clear pollutants, but none quite match the Dyson’s complete offering.
