Dyson Purifier Hot+Cool Formaldehyde Review

A brilliant tool to use all year round, the Dyson Purifier Hot+Cool Formaldehyde can cool you, warm you and it keeps your air clean.

Introduction

Dyson is constantly improving its fans, making them more and more useful, even when the weather isn’t particularly hot. The Dyson Purifier Hot+Cool Formaldehyde may well be the most useful fan it’s released, as it’s also a powerful air purifier (with formaldehyde detection) and a heater. In short, you can use this model all year round and see the benefit from cleaner air to a more comfortable environment.

It’s a touch expensive, and owners of the original Dyson Pure Hot+Cool may not find reason enough to upgrade. For anyone looking to get their first fan/heater/purifier, it’s an excellent choice.

Design

• The Dyson Purifier Hot+Cool Formaldehyde’s bladeless design still looks amazing
• New colour scheme makes this model stand out
• Easy to change filter
• Neat remote control storage

Dyson’s fans have always looked cool thanks to the bladeless design and now, years on, the Dyson Purifier Hot+Cool Formaldehyde still looks just as cool. This tower fan (764 x 248 x 248mm) has a gold-effect body, rather than the silver of previous models, highlighting that this is the model that can deal with formaldehyde.

It’s a subtle change but I like the new colour: it’s neat enough to stand out but not so much in your face that this fan will dominate the room.

Setting the fan up for the first time is easy, and you only need to clip the two-part filter into place. This comprises of an inner carbon filter for gasses and an outer HEPA filter that captures particulate matter (PM – small particles). Replacements cost £65, and each filter should last around a year, depending on use, although the fan will tell you when it’s time to change each one.

Features

• Lots of automation features lets the Dyson Purifier Hot+Cool Formaldehyde keep your room perfectly comfortable
• Can automate purification and temperature
• Diffuse mode is useful when it’s cold
• Excellent smart features

On the front of the fan, you’ll spot the LCD panel. This is where you can see information, both about the fan’s status (set temperature and fan speed), but also about the quality of air in your home.

There’s a generic air quality graph, but you can cycle through the fan’s available sensors to see what’s making your air dirty. You can see readings for PM2.5 (very fine particles that can get into your lungs; PM10 (larger particles that can cause breathing problems or asthma attacks); VOCs (volatile organic compounds, which are harsh chemicals that can be in old furniture and cleaning products); NO2 (nitrogen dioxide, which is a gaseous pollutant found in cars; and HCHO (formaldehyde, which is a carcinogenic compound found in some furniture, glues and paints).

Detecting formaldehyde has always been difficult because the sensors degrade over time. Here, Dyson has used a solid-state sensor, which will last the lifetime of the fan. Cleverly, there’s a catalytic filter in the fan that breaks down formaldehyde into harmless molecules of water and CO2; and this converter never needs replacing.

Being able to see clearly what’s causing problems can be helpful, beyond simply giving you information. For example, if you start cleaning and notice a spike in VOCs, you may want to switch brand of cleaner.

You also get temperature and humidity sensors to give you a final picture of what the air in a room is like.

Direct control is available through the remote control, which magnetically attaches to the top of the fan so that it’s hard to lose.

At its most basic, you can use the fan buttons to select a fan speed (10 speeds available), and use the temperature buttons to increase or decrease the temperature you want the fan to achieve (1C to 37C). When the temperature is achieved, the fan will switch to minimum speed automatically, so you can use this model to keep a room at the ideal temperature.

If you don’t want the heater any more, the Blue button puts the fan into cooling only mode, giving you manual fan speed back.

It’s the Auto button that really makes this fan stand out from the competition, as this uses all of those sensors I talked about to adjust fan speed automatically to keep your air clean and comfortable. With Auto mode, you’ll notice that the fan will up speed and slow down through the day, as the environment changes.

Cleverly, all of this can work with the heater, too, turning the heat on and off as needed, while mixing fan speeds to clear the air.

One thing about having a purifier in a fan is that you don’t always want to have a blast of air directed at you. Thanks to the Diffused mode, the Dyson Purifier Hot+Cool Formaldehyde can reverse airflow and blow out of the rear. This mode only works in Cool mode, and the heating elements are at the front.

There’s a Nighttime mode that reduces screen brightness and runs the fan at a maximum speed of 4. A timer mode lets you run a countdown timer for your choice of 30-minutes, 1-hour, 2-hours, 4-hours or 8-hours. Oscillation is available at 45, 90, 180 and 350-degrees, too, with a manual tilt that lets you lift up the fan head.

Get your smartphone out and hook the Dyson Purifier Hot+Cool Formaldehyde up to the Dyson Link app and this device becomes a powerful smart tool. Here, you get the same controls as on the remote, plus some extras.

Use oscillation, for example, and you can set the fan’s start position using the on-screen controls. That’s really clever, as you can have the fan focus on the exact area that you want.

Turn on Continuous Monitoring in the app, and the Dyson Purifier Hot+Cool Formaldehyde will run its fans at a very low setting when it’s off. If you get close, you can just about hear the fan, but it’s not loud enough to be distracting. The benefit of this mode is that your fan will constantly monitor the environment, letting you delve into the app to see how your air quality changes over time.

You can view graphs for each of the available sensors. As values increase, the colour of the graph line changes: going from green (good), through yellow and orange to red (bad). Using this information, I could see formaldehyde values typically increasing through the day, peaking at around 1pm, when the sun was at its hottest. It’s likely the higher temperature was causing a higher level of formaldehyde off-gassing from my old desk.

Scheduling lets you control the fan automatically, including setting the fan mode and temperature. With these settings, you can use the Dyson Purifier Hot+Cool Formaldehyde in place of a traditional smart thermostat in a room.

As well as app control, Dyson now supports the Google Assistant as well as Amazon Alexa. You can set pretty much every control, although simple on/off and fan speed settings are easier than, say, trying to turn on diffuse mode by remembering the exact words to use.

Alexa support is better than Google Assistant support in some ways, thanks to Amazon Alexa Routines. Now, the Dyson Purifier Hot+Cool Formaldehyde is fully controllable via the Alexa app, which means you can control everything with a routine. In my house, I have the fan turn off when the Philips Hue Motion Sensor doesn’t detect motion for 30 minutes; and I have it turn on to my preferred settings when the Ring Alarm in my office is set to Disarmed.

This level of control makes the Dyson Purifier Hot+Cool Formaldehyde a great tool for use in an outbuilding, or anywhere else you may want to control it automatically.

Performance

• The Dyson Purifier Hot+Cool Formaldehyde quickly clears the air
• Exceptionally quiet
• Powerful fan and heater
• Keeps a room’s air clean

I tested the Dyson Purifier Hot+Cool Formaldehyde as both a fan and an air purifier. Starting with the fan, I measured it at a maximum air speed of 3.8m/s at 15cm and a minimum of just 0.69m/s. At 1m, those figures changed to a powerful 2.1m/s at maximum and I couldn’t get a reading at minimum.

What this demonstrates is the range that the fan has, going between a super-gentle breeze to a full-on raging hurricane. It’s a constant stream of air with none of the buffetting that a traditional fan can get you.

Sound ranged from 39.26dB (background noise) on the lowest setting to a very quiet 56.8dB on maximum, which is quieter than the older model.

With the heater turned on, you get a directional blast of air that can directly warm you. I found that this fan was enough to keep my office at a consistent temperature and was a far neater overall package than my rigged up smart thermostat controlling a fan heater.

Dyson says that it can capture 99.95% of ultra-fine particles with this purifier, as well as dealing with formaldehyde and VOCs. It’s hard to test for formaldehyde, but the graphs from the app showed that when readings did creep up, the fan in auto mode was enough to deal with them.

Back to my normal tests, then. First, I sprayed insect killer, which is a source of particulate matter. Here, the Dyson Purifier Hot+Cool Formaldehyde took 1m 48s to clear the room.

Next, I lit a smoke pellet, which burns for 60 seconds and left the Dyson Purifier Hot+Cool Formaldehyde on Auto mode. Stepping outside, I let my Nest Protect be my guide to when the air was clear again.

I could see the fan sucking in the smoke and clearing the room, giving me a normal reading in 10m 39s – faster than with the older model.

Conclusion

Sure, the Dyson Purifier Hot+Cool Formaldehyde is expensive; go through my list of the best fans, best electric heaters and best air purifiers, and you could buy all three separate for less.

Don’t write off the Dyson Purifier Hot+Cool Formaldehyde, though. Buying three separate devices means controlling them separately and finding home for them. Here, you get an excellent fan, a brilliant purifier and a great electric heater in one neat package. And, this fan is smart, too, giving you app control and even letting you automate your home and how it works.

For people with the previous Hot+Cool model, there’s probably not enough reason to upgrade. Anyone looking for a great purifier that can be used all year round will find the Dyson Purifier Hot+Cool Formaldehyde a great choice.

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Verdict

It may be about as expensive as buying a separate fan, heater and air purifier, but the Dyson Purifier Hot+Cool Formaldehyde does it all in one neat package. And, it’s brilliant at all three jobs, doing them efficiently and quietly. Excellent smart controls finish off the package, giving you app and voice control, plus brilliant automation tools. The addition of formaldehyde detection and cleaning help clean your air of another dangerous element, but owners of the previous Pure Hot+Cool won’t find enough here to make upgrading worthwhile.

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