Peace of mind for $549

I have a lot of smart home devices, but I’ve never had one quite as “fire and forget” as the air purifier. After the initial setup, I so rarely go into its controls or app that I have to remind myself of how they work.

The Pure Cool (model TP04) resembles one of Dyson’s larger Cool fans. It has the similar hollow oblong shape, with the base pulling in air, then pushing it out of the upper “shell” via the company’s bladeless Air Multiplier tech. The main differences are the Pure Cool is taller, heavier to accommodate the filters and other tech in the base, and white in color.

The current generation is an evolution of Dyson’s first-gen Pure Cool air purifier. It costs $549 ($50 more than the previous version), and the upgrades mostly amount to a new and improved filter system (unfortunately incompatible with the first-gen device) and a versatile LCD indicator in front. Also, for when you want the improved air quality but not the cooling effect of a fan, there’s a setting that will push air out the sides, not the front.

Dyson says the filters should last you about a year, assuming the Pure Cool is operating about 12 hours a day. A replacement set will set you back about $80.

I’ve lived with the Dyson Pure Cool for a few months now, and I can say that of all the connected gear in my house, it’s the device that’s frustrated me the least. In Auto mode, the purifier generally just takes care of itself and leaves you alone while it does its job. And on the lowest fan setting (which is what it was on most of the time), it’s so quiet you don’t even notice it.

Justification for an air purifier

Let’s back up a bit. An air purifier isn’t quite as much of a staple as other home appliances (like air conditioners or even humidifiers), so why should you even consider one?

If you live in an area with semi-permanent smog (like many major cities in Southeast Asia), the answer is pretty obvious. But even for less grimy areas, like my town in Northern New Jersey, there are benefits. Pollen season can flare up allergies, and in the winter it’s not unusual to go days or even weeks without opening a window. Not to mention many areas in North America suffer from , whose resulting smoke can seriously mess up air quality over large regions.

OK, so there’s a good chance you’ll benefit from an air purifier. But how do you know it’s doing anything? This is why Dyson turned the Pure Cool into one of the company’s only real “smart” devices. An air purifier shouldn’t just push out clean air blindly — it needs sensors to continuously gauge the quality of the air so it can make adjustments or even turn itself off.

On top of that, it should have some idea of the overall air quality outside. Dyson gets that data from unspecified third parties, and the accompanying app vividly shows what the air’s like both inside and outside your home on a single screen with stark colors. The visually friendly, informative app is one of the best features of the Pure Cool, a nice example of what a good smart-device app should be.

Purity in design

The design of the purifier isn’t bad either. The hollow-tower shape is signature Dyson, but the choice of glossy white for the top shell is a departure from the company’s Hot and Cool fans, which lean toward bolder colors like purple and blue. However, the white gives more than a hint of the device’s medical intent. “Pure” is definitely an apt descriptor. (Dyson also sells a smaller desktop version with a circular fan, the $449 DP04.)

One look at the silver base, and you know this thing is serious business. Inside is all the filter, sensor, and smart tech, and there’s a small circular display that’s capable of showing an impressive amount of information — not just about the purifier operation, but also current and recent air quality.

What I really like is how the Dyson Pure Cool breaks down exactly what might be contaminating your air and how far it is from the ideal. By default, the screen shows overall air quality on a graph with clearly marked green, yellow, and red areas. The worse the air, the higher on the graph you’ll be, and the harder the Pure Cool needs to work to get you back in the green.

If you press the “i” button on the remote, the screen will break down, one at a time, the four factors that contribute to the overall air quality. The first two tell you the levels of microscopic particles, first on the PM2.5 scale (basically particles 2.5 microns wide or smaller) and second on the PM 10 scale (~10 microns). The third tells you the concentration of VOCs (volatile organic compounds), potentially dangerous chemicals like benzene. Finally, it shows how much nitrogen dioxide (NO2), which can contribute to diseases like asthma, is in the air.

The info gets 10x better when you fire up the Dyson Link app ( and ), which serves as the central hub for the company’s smart products (although there are only two, the Pure Cool and the ). Where the purifier’s indicator shows just basic screens with some pictographs, the app shows you detailed graphs for each factor along with temperature and humidity over time. (The purifier indicator can show the current temp. And humidity, but not on a graph.) There’s also lots of extra info, just a finger-tap away, to help interpret the graphs you’re looking at.

Superior app

Dyson really scored in designing this app. The home screen is simple, but it can also be dramatic if there’s a big difference in air quality between indoors and outdoors. The screen shows your house as a solid color and the surrounding air as a lighter one, both using the intuitive color coding of green, yellow, red to indicate quality. If one is green and the other is yellow (or worse, red), your eye knows something is amiss very, very quickly.

The app also replicates all the buttons of the remote control, so you don’t need to worry about hunting it down every time you want to do something. Moreover, you can control your air purifier from anywhere — par for the course when you’re talking about smart devices, sure, but still notable.

The feature that makes the Pure Cool truly effortless is the scheduler. Marked by the on-the-nose clock icon in the corner, it lets you set up specific times for the purifier to run, and which settings to use. For example, if know the air quality around your house tends to get worse later in the evening (as is the case for me), you might set it to turn on at dusk, with the fan on a relatively high setting.

Generally, though, when I had the Pure Cool on, I kept it on Auto mode, which automatically picks the fan speed based on what the air quality is. The scheduler lets you break down the Pure Cool’s operation hour by hour, for every day of the week, if you want to.

You can set the fan speed at a level from 1-10. At lower settings the fan is whisper quiet, to the point where I was comfortable leaving it on in my bedroom all night long. However, it does tend to get loud on the higher end. That might discourage you from leaving the fan in Auto mode at night, but there’s a saving grace: Night Mode, which keeps the fan from ever going above level four, even when it’s in auto mode.

Air master

Once I’d mastered these settings, the Pure Cool became the least needy of all my smart home gadgets. Even when I unplugged it and moved it from room to room, it remembered all its settings and generally took care of itself. Even the most benign kitchen gadget will bother you with a firmware update from time to time. About the most annoying thing the Dyson did was occasionally get a bit loud.

Did Pure Cool do its job? I could point to the large archive of graphs in the app to show that it did, but mostly I’d point to my peace of mind. It’s not like wildfires rage outside my home on a regular basis, but I do take seriously the air my family is breathing on a daily basis. While nothing can guarantee good health, the Dyson Pure Cool at least gives you one less thing to worry about.