The Dyson Purifier Hot+Cool Formaldehyde HP09 is an all-in-one fan, space heater, and air purifier. It's quite similar to the Dyson Purifier Hot+Cool HP07 in terms of overall size and internals. That said, the HP09 differs with the inclusion of a separate catalytic filter that's meant to destroy formaldehyde. You can also operate it remotely using the MyDyson smartphone app or with voice assistants like Amazon Alexa or Siri.
Our Verdict
The Dyson HP09 is a middling option for pet owners. It falls short of some alternatives when it comes to capturing really fine particles like cat dander, and it has a somewhat low clean air delivery rate. If your pet is sensitive to loud noises, it's also best to leave the heater off—while it isn't all that loud at its lowest fan speed, it does become somewhat noisy with the heat cranked to the maximum setting.
- Central display provides a wide range of info.
- Automatic fan speed adjustment system.
- You can operate it via smartphone app or included remote control.
- Middling particle filtration performance.
- Low air cleaning rate.
- Noisy when heater is engaged.
The Dyson HP09 is decent for use in bedrooms. It's small enough to be set up in any corner of your room, and as long as you don't turn on the heater, it doesn't make all that much noise. It also features a dedicated 'Night' mode, limiting the fan speed to its quietest level and dimming the display. That said, the HP09's actual particle filtration performance isn't all that great, and its low clean air delivery rate means that it's really only suited for smaller bedrooms.
- Central display provides a wide range of info.
- Automatic fan speed adjustment system.
- You can operate it via smartphone app or included remote control.
- Middling particle filtration performance.
- Low air cleaning rate.
- Noisy when heater is engaged.
- Central display provides a wide range of info.
- Automatic fan speed adjustment system.
- You can operate it via smartphone app or included remote control.
- Middling particle filtration performance.
- Low air cleaning rate.
- Noisy when heater is engaged.
- Central display provides a wide range of info.
- Automatic fan speed adjustment system.
- You can operate it via smartphone app or included remote control.
- Middling particle filtration performance.
- Low air cleaning rate.
- Noisy when heater is engaged.
Performance Usages
Changelog
- Updated Nov 04, 2025: Version 1.0.2 of our Air Purifier Test Bench rectifies calculation errors in our existing Particle Filtration Rate test to provide more representative results of some units. For a more detailed breakdown of the changes made, see our full changelog.
- Updated Oct 31, 2024: Converted to Test Bench 1.0.1.
- Updated May 13, 2024: Review published.
Check Price
Differences Between Sizes And Variants
This device comes in two variants, though they differ only in color. The HP07 is available in White/Gold or Nickel/Gold colorways. We tested the White/Gold version; you can see its label here.
Let us know in the comments if you encounter another variant of this machine.
Popular Air Purifier Comparisons
The Dyson HP09 is a premium all-in-one device that can act as an air purifier, heater, or cooling fan. That said, as far as actual air filtration performance goes, it does little to distinguish itself from much cheaper devices, which offer a similar range of hands-off functionality like smartphone app integration and particle detection.
The Dyson Purifier Hot+Cool Formaldehyde HP09 is a little more feature-rich than the Dyson Purifier Hot+Cool HP07, though both appliances will deliver similar overall performance in most scenarios. Only the HP09 has an added catalytic filter for trapping formaldehyde, a colorless gas that a huge variety of indoor sources can release, ranging from paint to particleboard. That said, we don't currently test for formaldehyde absorption, and are unable to validate this claim.
Test Results
This central display provides information on a room's current air quality based on the concentration of different types of pollutants. You can view levels of PM2.5 particles, PM10 particles, Volatile Organic Compounds (VOCs), nitrogen dioxide, and formaldehyde. The indicator strip along the side of the display changes color depending on current pollutant levels.
- Green: Good
- Yellow: Fair
- Orange: Poor
- Red: Bad
This air purifier also comes with a remote control that allows you to change the air purifier's fan speed, adjust the main fan's oscillation, cycle through particle count info, change the heating intensity, or enable the device's Night mode, which dims the display and sets the fan to its quietest setting. This remote is magnetized; you can set it on top of the fan where it's held in place when not in use.
This air purifier has a four-stage filter system that includes a HEPA filter for particles like mold spores, pollen, and pet dander, an Activated Carbon layer for locking in odors, and a catalytic filter for capturing formaldehyde, a colorless gas that a huge variety of indoor sources can release, ranging from paint to particleboard.
The manufacturer doesn't issue maintenance requirements for the filter system. You must replace the combined HEPA/Carbon filter every year. You can buy a replacement here. The catalytic filter doesn't need replacing and is intended to last for the machine's lifetime.