The Dyson Purifier Humidify+Cool PH2 De-NOx is a multifunction smart air purifier that uses HEPA and carbon filtration to remove harmful airborne pollutants and employs ultraviolet cleansing technology to deliver cool, clean, moist air. It offers numerous air quality readings and uses Matter technology to integrate with Alexa, Google, HomeKit, and SmartThings home automation platforms. At $1,099.99, it’s one of the more expensive air purifiers I’ve tested, but it is also among the most feature-rich and is worth the expense if you want to humidify the air that you breathe. If you don’t require humidification, the Dyson Hot+Cool Formaldehyde HP09 ($849.99) isn't Matter-enabled, but it heats, cools, and purifies, and it’s considerably less expensive than the PH2, so it remains our Editors' Choice.

Design: A Minimalist Tower With Premium Finishes

The Humidify+Cool PH2 De-NOx uses the same gold-and-nickel oval tower design as the Hot+Cool Formaldehyde HP09. It stands 36.3 inches tall, has a base diameter of 12.3 inches, and weighs 17.9 pounds, making it taller and heavier than the HP09, which stands 30 inches tall and weighs 12.6 pounds. It uses multiple sensors to measure air quality, room temperature, and humidity levels.

(Credit: John R. Delaney)

The top half of the purifier features a glossy white, bladeless amplifier loop fan that distributes clean, hydrated air throughout the room. It uses Dyson’s Air Multiplier technology to circulate purified and hydrated air. Two airflow outlets on either side of the loop can be configured for 0, 45, or 90 degrees of oscillation action. The bottom half of the PH2 pulls air into the three-stage filtration system. Behind a removable panel sits the HEPA+K-Carbon filter and a catalytic filter.

Features: Advanced HEPA Filtration, Humidification, and Precision Airflow Control

The HEPA+K-Carbon consists of two semi-circular filter components. The K-Carbon element captures up to 50% more nitrogen dioxide (NO2) gases than a typical carbon-activated filter, according to Dyson. It also removes odors and Volatile Organic Compounds (VOCs), which are carbon-based gases that are found in certain building materials, paints, and some household cleaners. The H13-grade HEPA filter can remove 99.97% of particles as small as 0.3 microns, including dust, pollen, smoke, and pet dander, and the catalytic filter breaks down formaldehyde gases into small amounts of carbon dioxide (CO2) and water. The HEPA+K-Carbon filter is rated to last up to one year, with replacements costing $89.99 each. That’s a bit more expensive than the HP09 filters, which cost $79.99 each. The catalytic filter is permanent and does not need to be replaced.

(Credit: John R. Delaney)

The base of the purifier holds a one-gallon water tank for humidification. To add water, press the two release buttons on either side of the tank and use the built-in handle to carry the tank to your sink. Once filled, make sure the tank and fill cap are completely dry before reinstalling them in the purifier. Depending on your water hardness, the humidifier will need a deep cleaning from time to time. Dyson ships the PH2 with a citric acid cleaning kit, and the app will tell you when it’s time for a cleaning and provide detailed instructions.

Between the top and bottom halves of the purifier, there's a power button, a Deep Clean button, and a small, round RGB LED screen that displays air quality statistics. You can use the included remote to toggle through the various readings, which include overall air quality, PM2.5 (particulate matter with a diameter of less than 2.5 microns such as harmful gases), PM10 (particulate matter with a diameter of less than 10 microns such as dust, pollen, and other airborne bacteria), HCHO (formaldehyde), VOCs, NO2, room temperature, and humidity. Other readings include Wi-Fi status, remaining filter life, and when it’s time for a deep cleaning. The Deep Clean button will also illuminate when it's necessary.

The 10-button remote is magnetic and can be attached to the top of the purifier. Use it to power on the purifier, cycle through the above-mentioned readings and settings, set the fan speed (1 to 10), enable Auto Purify mode (which allows the various air quality sensors to determine fan speed), and enable Auto Humidity mode (which uses the humidity sensors to adjust the humidifier settings). You can use the up/down button to manually set humidity target levels. Other buttons let you control oscillation, change the airflow direction from front to back, set a sleep timer, and enable Night mode, which dims the LCD and runs at the quietest fan setting.

Smart Controls: App Integration and Full Matter Compatibility

The PH2 uses the same My Dyson mobile app (available for Android and iOS) as other Dyson purifiers, and because it supports the Matter smart home connectivity standard, it can also be controlled via Alexa, Google, HomeKit, and SmartThings apps and voice commands. The purifier appears on the mobile app’s My Products screen, which contains a graphic of a house and a picture of the purifier. The top of the screen displays the device name and outdoor air quality and temperature readings (based on your location), and below that are indoor air quality, temperature, and humidity readings from the PH2. The air quality reading shows the most prevalent type of pollutant currently present. Indoor air quality is represented by different background colors: green is good, yellow is fair, orange is poor, red is very poor, dark red is extremely poor, and purple is severe.

(Credit: Dyson/PCMag)

To access the control screen, tap the purifier icon. Here you can power the device on and off, enable Auto Humidity and Auto Purify, change the fan speed and/or airflow direction, set a humidity target, turn on oscillation, set a timer, and enable Night Mode.

At the bottom of the device screen are power, fan speed, humidity level, oscillation, and remote buttons (the remote button takes you to the above-mentioned control screen). A gear icon at the top of the screen lets you access device settings, create a schedule, link the purifier to Apple Home and Alexa, and view a 10-day air quality report.

Setup: Quick and Straightforward Installation

Preparing the PH2 for first use was easy. I removed the packing materials from the HEPA+K Carbon filter and the water reservoir, plugged in the purifier, and powered it on. I downloaded the mobile app, created an account, and tapped Add Product on the My Products screen. The app immediately identified the PH2, so I selected it and followed the instructions to hold my phone close to the device for pairing. I pressed the power button, and the purifier instantly paired with the mobile app. I selected my Wi-Fi SSID, entered my password, and after a few seconds, the purifier was connected to my network. I entered the room name and the purchase date, and the PH2 was ready for action.

(Credit: John R. Delaney)

Performance: Rapid Air Cleaning With Consistent Humidification

The PH2’s air purification performance was nearly identical to that of the HP09 in testing. I set it up in my 110-square-foot office, where it produced an initial PM2.5 reading of 01, then lit an incense stick, and let it burn for around 10 minutes. Once the PM2.5 reading hit 200, I set the purifier to Auto mode, and the fan immediately kicked into high speed. After three minutes, the reading dropped to 96, and after six minutes it lowered to 51. After ten minutes, the PM2.5 measurement hit 23, and after a total of 21 minutes, it had returned to its initial reading of 01. The HP09 needed 19 minutes to return a 01 reading.

The PH2 did an excellent job maintaining a 45% humidity level in my 360-square-foot bedroom, and the fan was relatively quiet at lower speeds. However, once I started bumping up the fan speed, it got a little noisy. Using the NIOSH Sound Level Meter iPhone app, I measured an output of 58dB when running at level five and 78dB at level 10, the highest speed. Not surprisingly, the HP09 delivered the same readings.

Alexa and Siri voice commands to turn the purifier on and off and to set the fan speed worked flawlessly, as did my HomeKit automation to have the purifier turn off when I left the house.