I Tried the Dyson Purifier Humidify+Cool PH04: Is This Machine Worth Its Hefty Price?

The Dyson Purifier Humidify+Cool Formaldehyde PH04 is an all-in-one unit that serves as a humidifier, fan, and air purifier. I put it to the test to see how well it performs.
Dyson Purifier Review

Photo: Stephanie Cronk

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Starting as a floor-care brand in 1991, Dyson made a name for itself with its patented cyclone air technology. Since Dyson is well known for its innovative products, high-quality builds, and outstanding customer service, when I found myself in the market for a humidifier that also purifies, Dyson was a clear contender.

Over the years, the brand has expanded its offerings to encompass a range of household products, including bladeless fans and air-quality products such as its PH04. The Dyson PH04 is an all-in-one unit that claims to cool, purify, and humidify the air in a home. It is a direct upgrade from the PH03, as the newer unit also filters out formaldehyde.

Because we have radiant floors and a wood stove as our two primary heat sources, our home’s air becomes incredibly dry in the cooler months. When we noticed cracks in our ceiling, it became apparent that we needed a quality humidifier that could add the proper moisture to our home before more damage could occur. Enter the Dyson Purifier Humidify+Cool Formaldehyde PH04.

Dyson Purifier Humidify+Cool Formaldehyde PH04: At a Glance

Dyson Purifier Review
Photo: Stephanie Cronk

Rating: 9.7/10


  • Automatic humidify or purify settings that detect air quality and set the automatic fan speeds
  • Sleek and modern design fits nicely into any decor without being an eyesore
  • Large water tank has an easy-to-carry handle and holds enough water to last hours without needing a refill
  • Night mode offers quiet operation to ensure a restful night of sleep


  • Only 1 automatic setting can be applied: purify or humidify

Get the Dyson Purifier Humidify+Cool Formaldehyde PH04 at:

What is the Dyson Purifier Humidify+Cool Formaldehyde?

The Dyson PH04 Purifier Humidify+Cool Formaldehyde is a purifier, humidifier, and fan all in one. It uses AutoReact technology to automatically sense, capture, and trap pollutants for cleaner and fresher air, and it also has the ability to detect and destroy formaldehyde (which is released from wood flooring and fabric). Additionally, the unit works to add moisture to the room with its humidifying function.

Weighing 18 pounds and featuring wheels to easily transport it from room to room, the Dyson comes with 90-degree-angle oscillation and has 10 speed settings. At just over 36 inches high and 12 inches in diameter, it does take up some real estate, but much less than the bulky square humidifiers commonly seen on the market. I liked its circular shape, which allows it to tuck nicely into a corner. The Dyson PH04 features a fully sealed HEPA H13 standard filter, and its Air Multiplier technology circulates purified, humidified air throughout the whole room. It has the ability to:

  • Monitor, purify, and humidify with its quiet settings and dimmed display;
  • Capture wildfire smoke; and
  • Thoroughly eliminate mineral buildup throughout the water system at the touch of a button.

You can choose from among three settings: Fan mode for direct cooling with a choice between 0 and 90 degree oscillation, Breeze mode to mimic a refreshing breeze, and Backward airflow mode to purify and humidify without cooling. You can control the machine with simple spoken instructions or with the curved and magnetized remote, which stores neatly on top of the machine when not in use. The PH04 can be programmed to turn off after preset intervals between 30 minutes and 8 hours, and it works with both Amazon Alexa, Siri, and Google Assistant.

Dyson offers two color options to choose from: nickel and gold or white and gold. We tested the nickel and gold option.

Dyson Purifier Review
Photo: Stephanie Cronk

Is the Dyson humidifier and purifier hard to set up?

The Dyson air purifier and humidifier came well packaged and was easy to set up. After removing the packing tape from the unit itself, I simply had to fill the water tank to the fill line, slide it into the bottom of the unit, plug it into a wall outlet, and turn it on. I had the unit up and running within 5 minutes of unboxing. The manual states that tap water is safe to use; however, since my home has very hard water, I used distilled water to ensure the longevity of the product.

The Dyson PH04 connects directly to the Dyson app. After I downloaded the app, connection took mere seconds as it automatically scans the home for Dyson appliances. While the app serves as a second remote and air-quality monitor, the magnetic remote control was easy to use to set the desired humidity level and fan speeds. The Dyson app also works as a remote, so you can control the unit from other rooms in the house, or even while you’re out of the house.

Is the Dyson PH04 easy to use?

I set the Dyson in my living room, which is also where my wood stove is, making it the driest room in the house. Between the burning wood, the smoke escaping from the stove every time we opened the door to add wood, and the stove’s proximity to the kitchen, the living room seemed to be the logical place to set it up, and also where the air quality would likely be at its lowest.

Dyson certainly has the user in mind with the design of this all-in-one humidifier. You can power on the Dyson by pressing the button directly on the unit, using the remote control, or using the app. I tested all three ways, and all worked flawlessly. Once the unit was powered on, I was able to monitor the air quality and air humidity levels via the LCD screen on the front of the unit. For on-the-go monitoring, you can use the Dyson app, which offers a more in-depth view of a home’s air quality.

If you’re using the Auto Purify or Auto Humidify mode, the unit will automatically adjust the fan settings based on the air quality or dryness. You can override the auto settings with the remote by pressing the up or down arrows to adjust the fan speed.

When the water tank (which is located at the bottom of the unit) needs to be refilled, the unit will alert you. Simply hold the release buttons on both sides of the unit and slide the tank out. The tank has an easy-to-carry handle, and it’s easy to refill and slide back in. When sliding it back in, make sure the tank locks into place with a click.

I found that a full tank of water could last up to 2 days when my home’s humidity levels were maintained. When the air was particularly dry—for example, on colder days when the wood stove was burning at a hotter temperature—the water in the tank would still last for more than 12 hours.

Dyson Purifier Review
Photo: Stephanie Cronk

How well does the Dyson humidifier, purifier, and fan work?

The Dyson PH04 operates efficiently when it’s on the fan mode. You can select the desired fan speed, and the unit reacts quickly and quietly. The fan oscillates at 45 or 90 degrees, and my family and I found the fan to be adequate for cooling our living room and circulating the warm air that the wood stove emits. The unit also features a reverse mode, so you can direct air behind the unit if you do not want it blowing directly on you.

While I originally planned to use the humidifying feature of this unit, I found myself going back to the air-purifying feature over and over. The connected Dyson app measures the air quality constantly. I noticed significant spikes when I was blow drying my hair in an adjacent bathroom, which I thought was odd. After doing some research, I found out that electric hair dryers are a common source of ultrafine particulate matter, commonly known as PM2.5. Sure enough, when anyone in the house ran the blow dryer, the PM2.5 meter would spike on the unit’s display and the app.

As long as the unit is set to Auto Purify, when any of the measured pollutants spike, the unit kicks into high gear until the air quality is brought back to normal. I also noticed this happening anytime I would cook dinner in the kitchen, which is adjacent to the living room where the unit was plugged in. This made more sense to me, as oils and fats can release volatile organic compounds (VOCs) into the air. Again, the unit would kick on and run at a higher fan speed until the air was returned to “Good” quality.

The humidifying function worked as expected. As I mentioned, the unit was placed in the same room as the wood stove since the wood stove causes extremely dry air and has even caused cracks in our sheetrock due to the dryness of the air. I used a hygrometer to measure the humidity level in the living room. While the PH04 also constantly measures the humidity level when it’s turned on, I wanted to have a second source to check the accuracy of the unit.

My hygrometer measured the humidity level at 31 percent after my wood stove had been pumping for about 3 hours. The temperature in the living room was a balmy 79 degrees Fahrenheit. I set the unit to Auto Humidify with a preset humidity level of 50 percent. Within an hour, the Dyson had increased the overall humidity in the room to 43 percent, and within 2 hours, it had reached my set humidity level of 50 percent. Once the unit hits the desired level, the fan automatically adjusts down to a lower fan speed to maintain the proper level.

Overall, I found the Dyson’s three features to work efficiently and effectively. I especially enjoyed being able to track my humidity levels and air quality via the Dyson app, and I found myself checking the app multiple times throughout the day.

Dyson Purifier Review
Photo: Stephanie Cronk

Does the Dyson Purifier Humidify+Cool air purifier work for smoke?

As an Upstate NY dweller, we have recently been hit with wildfire smoke coming from the wildfires burning in Canada. Our air quality plummeted, visibility decreased, and overall pollution in the air has spiked. The Dyson air purifier has been working non-stop to purify the air within my home. The air quality within my home has dropped to “Very poor” on multiple occasions over the course of a week. When this happens, the air purifier kicks into high gear and operates on a high level until the air quality returns to “Good.” When the air quality hit “Poor” quality, it remained at a high operating level.

Overall, I have been very impressed with how this unit has tackled the wildfire smoke. On the first day of poor air quality outside of my home, I had my windows open, after closing them and turning the Dyson on, the smoke smell dissipated within an hour, and the air quality went from “Very Poor” to “Poor” within 2 hours. My home is an open floor plan, so I thought this was pretty quick considering the amount of air the Dyson is trying to purify.

Is the Dyson Purifier Humidify+Cool worth the money? 

The Dyson Purifier Humidify+Cool is an expensive unit compared to some of its competitors. The PH04 is the formaldehyde version, so it detects formaldehyde in the air and uses its catalytic filter to continuously trap and break down formaldehyde molecules. However, Dyson does offer a cheaper version: The PH03 offers some of the same features, but it lacks the ability to break down formaldehyde.

Overall, at a higher price of over $900, the Dyson offers quite a bit for the cost. It’s sturdy and well built, and it can move easily from room to room if needed. The water tank holds enough water to last for days, depending on the humidity level of the room, and it has a sturdy build to it as well. I feel the Dyson is well worth its high price tag with its ability to clean my air efficiently and add moisture when needed. I also love the fact that I can use this unit for just its fan feature, too, which helps move the hot, stagnant wood-stove air around my home.

Where to Buy the Dyson Purifier Humidify+Cool PH04:

Get the Dyson Purifier Humidify+Cool Formaldehyde PH04 at:

Meet the Tester

Stephanie Cronk brings over 12 years of retail and digital publishing experience to the Commerce/Product Reviews team as Executive Editor. Her experience spans many industries in the commerce world, and her primary focus is on buyer’s guides and tested product reviews.


Stephanie Cronk

Executive Editor

Stephanie Cronk joined the Bob Vila team in 2020 as the executive editor of Commerce, bringing over 12 years of retail and digital publishing experience to the Commerce/Product Reviews team. Her experience spans many industries in the commerce world, and her primary focus is on buyer’s guides and product reviews.