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Dyson Purifier Cool Formaldehyde TP09 review: Running out of juice

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At first sight

Expert evaluation


Does double duty with a cooling fan Formaldehyde detection and destruction system could be a game changer for some A conversation piece, design-wise


Relatively low clean air delivery rates (CADR), given its price It takes some time to unpack and set up Pricey, both in advance and to replace its filters

Our verdict

Dyson kills it on the design front as usual, but this purifier can’t match the power of other units in its price range.

Price at time of review


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Retail price

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Like nearly everything Dyson makes, its air purifier is unique in every way. From design to functionality to the name of the device, the Dyson Purifier Cool Formaldehyde is a unique and original (and very expensive) air cleaner.

Let’s start with that name: Cool Formaldehyde doesn’t exactly roll off the tongue, but both words have relevance. “Great” because the purifier is also a fan, obviously without a blade. “Formaldehyde” because the unit features a special sensor and catalytic filter specifically designed to detect and destroy formaldehyde, a harmful chemical that can be found in everything from insulation and plywood to cosmetics and dish soap. In other words, your house is probably full of the stuff, and since formaldehyde is a gas, a standard HEPA filter can’t remove it.

This review is part of TechHive’s in-depth coverage the best air purifiers.

If the formaldehyde spectrum is something keeping you up at night, look no further than this unit, which tracks not only levels of that chemical but also nitrogen dioxide, other VOCs (volatile organic compounds), and both PM2.5 that Levels of PM10 (particles with dimensions of 2.5 and 10 microns respectively). A battery of filters, four separate filter components attached to the purifier, removes all that stuff. (More on this in a moment.)

origin 1The Dyson Pure Cool Formaldehyde TP09 uses filters to capture particulate matter, but it can also trap and destroy formaldehyde.


The Dyson TP09 is certified under the Asthma & Allergy Friendly certification programme Asthma and Allergy Foundation of America and Allergy Standards Limitedbut its CADR numbers (clean air delivery rates) are hard to come by, in part because Dyson he doesn’t really believe it. A little digging will show up some specs, revealing stats of 82 cfm (smoke), 92 (dust) and 101 (pollen) and a maximum supported room size of 127 square feet. These numbers are all particularly low for a machine of this size and price. And thanks to the fan function, the unit can be quite loud even at relatively low speeds; my wife said she thought it was too loud to turn on at night even in sleep mode.

The unique design of the Dyson TP09 draws air through its base and instead of using one cylindrical filter, the Dyson requires four semi-circular filters, two stacked on each side. Two of the filters are HEPA H13 particulate filters, while the other two are carbon-fired units for the removal of odors and VOCs. The Dyson catalytic filter is a separate device that sits somewhere inside the purifier. It never needs replacing, but other filters will run you $80 per replacement set. (Filters are expected to last about 12 months, according to the company.) While putting all of these things together takes a while, and is less intuitive than I’d like, the app portion of the setup process is quick and painless. connecting the unit to your 2.4GHz Wi-Fi network in minutes.

origin 1Dyson’s app makes the combined air purifier and fan easy to use and control.

Christopher Null/Foundry

The purifier weighs 10 pounds and measures an inconspicuous 41 inches tall, most of which is dedicated to the bladeless fan. The system can rotate and swing through 350 degrees of motion and the direction of the airflow can be adjusted between 10 speeds and even reversed if desired. Auto and night modes are also available on the included tiny remote, but the unit itself only includes a power button and a small color LCD status screen that gives you a glimpse of environmental conditions, filter life, and the like.

You’ll get much more detailed information about your room from the Dyson app, which provides all the same remote control controls, plus a timer system. (Note that there is no scheduling system available, although Alexa and Google Home systems are supported as a workaround.)

origin 1Make sure you activate Dyson’s ‘continuous monitoring’ mode to collect environmental data whether the unit is on or off.

Christopher Null/Foundry

All of the various pollutants tracked by the TP09 can be tracked in the app, but you’ll have to scroll to various parts of the main screen to find them all. (Scroll up and you’ll find a graphical tracking system for each pollutant, as well as temperature and humidity. All of this is tracked on a daily basis.)

Is Dyson’s air purifier a good value? All in all, there’s a lot to like about the Dyson Purifier Cool Formaldehyde TP09 air purifier, including its fan, a host of pollutant-sensing features, and that unique formaldehyde-killing technology. That said, the limited horsepower and high price tag of the TP09 will be dealbreakers for some buyers.