The Dyson Purifier Big+Quiet Formaldehyde BP04 and BP03 are Dyson's flagship air purifier models. The two are very similar in design, the only difference being that the more expensive BP04 is fitted with a CO₂ sensor and comes with an improved activated charcoal filter. Both air purifiers have the full suite of Dyson features, with Wi-Fi connectivity, automatic fan speed adjustment, and a variable angle fan.
Our Verdict
The Dyson BP04 and BP03 are great options for pet owners. Both are equipped with HEPA filtration systems and won't have much trouble capturing finer airborne particles, like pet dander. They also make very little noise, especially for large and relatively powerful machines, which is good if your pet is particularly sensitive to loud noises. The long-lasting filters and automatic fan speed adjustment features also result in a hands-off ownership experience.
- Quiet operation.
CADR is sufficient for most bedrooms and smaller living spaces.
The Dyson BP03 and BP04 are excellent for use in bedrooms. While both models are absolutely enormous for air purifiers and require a fair amount of space, the bottom-mounted casters make them a little easier to place. They also run very quietly, and the built-in light sensor automatically dims the display in darker rooms. It also offers very good overall air purification performance and won't have too much trouble in larger rooms. That said, unless you're specifically worried about high carbon dioxide levels in your home, the cheaper BP03 model will do fine.
- Quiet operation.
CADR is sufficient for most bedrooms and smaller living spaces.
- BP04 model is fitted with a CO₂ sensor.
- Wide variety of automatic features.
- Large size.
The Dyson Purifier Big+Quiet Formaldehyde BP04's particle filtration rate is good. At its highest fan speed setting, it can lower particle counts in a moderately sized room within a reasonable time, though there are alternatives that can do the same task even faster. It's best used in spaces like a bigger dining room or living room, and is likely to struggle in areas larger than that.
CADR is sufficient for most bedrooms and smaller living spaces.
Changelog
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Updated Feb 11, 2026:
We've updated the text in this review to reflect new tests added with version 1.1 of our test bench.
- Updated Feb 11, 2026: Version 1.1 of our air purifier testing methodology provides a more representative summary of unit performance, with a revised Particle Filtration Rate test conducted in a better-sealed environment and a more reliable means of generating consistently sized particulate matter. We've also included a parameter for the machine's maximum recommended room size. For a more detailed breakdown of the changes made, see our full 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.
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Differences Between Sizes And Variants
The Dyson BP04 and BP03 are both high-end air purifiers with only slight internal differences.
| Model Name | Filter System | CO₂ Sensor | Accent Color | Notes |
|---|---|---|---|---|
| BP03 | HEPA Filter + Activated Carbon Filter | No | Bright Nickel/Prussian Blue | - |
| BP04 | HEPA Filter + Activated K-Carbon* Filter | Yes | Prussian Blue/Gold | Exclusive to Dyson online store |
We tested the BP04 model; you can see its label here.
Let us know in the comments if you encounter another variant of this device.
*The manufacturer advertises the Activated K-Carbon Filter to provide additional protection from NO₂ versus the standard Activated Carbon Filter.
Popular Air Purifier Comparisons
The Dyson Purifier Big+Quiet Formaldehyde BP04 and BP03 are high-end air purifiers. They easily outperform the brand's cooling fan/air purifier/space heater combos, like the Dyson Purifier Hot+Cool Formaldehyde HP09, in actual filtration performance. They also operate quietly, which is rare for something this big that generates relatively substantial airflow. Like many other Dyson products, they're also very intuitive to operate. With all that said, other premium air purifiers on the market offer similarly superb air purification performance, like the NuWave OxyPure, which can deliver the same level of performance for a lot less.
If you're interested in alternatives, you can see our recommendations for the best air purifiers for pets, the best air purifiers for bedrooms, and the best large room air purifiers.
The Dyson HEPA Big+Quiet Formaldehyde BP06 is effectively a simplified version of the more expensive Dyson Purifier Big+Quiet Formaldehyde BP04, being intended more for use in commercial or public areas. The BP04 has 10 fan speed settings compared to the BP06's two. The BP06 also lacks in-app connectivity, so you can't adjust settings remotely, and it's unable to change its fan speed in real time according to current pollutant levels. Otherwise, all models have the same three-stage HEPA 13 filtration system, though only the BP04 comes bundled with an activated K-Carbon filter, which is advertised to provide additional protection from NO₂ versus their standard activated carbon filter.
Test Results
This device's central display provides quite a bit of information. You can cycle between live views of PM2.5 particle concentration, PM10 particle concentration, Volatile Organic Compound (VOC) levels, formaldehyde levels, and nitrogen dioxide levels. This device also provides a rundown on current temperature and humidity. However, only the higher-end BP04 model has an additional carbon dioxide sensor. Like most of Dyson's other air purifiers, the indicator on the left of the display changes based on the current air quality.
- Green: Good
- Yellow: Fair
- Orange: Poor
- Red: Bad
You can also view all these metrics through your phone if you've paired your air purifier to the MyDyson companion app.
This air purifier also comes with a remote control that allows you to operate it from afar.
This air purifier has a three-stage filter system comprised of a H13-rated HEPA filter with a separate mesh layer for dealing with the usual assortment of bacteria, mold spores, pollen, and pet dander, along with an Activated Carbon layer for minimizing odors and gases. It's worth noting that the BP04 comes bundled with an Activated K-Carbon filter, which is supposed to provide additional protection from nitrogen dioxide compared to the BP03's standard-fit Activated Carbon filter.
The manufacturer doesn't issue any maintenance requirements for the filter system. That said, you'll need to replace the activated carbon filter every two years, and you can find replacements here. You can also find the pricier K-Carbon filters here. Meanwhile, the H13 HEPA filter has an estimated lifespan of five years. You can find a replacement here.
The Dyson Purifier Big+Quiet Formaldehyde BP04's particle filtration rate is good, but not great. Despite its large footprint, its actual max CADR lags behind that of smaller alternatives like the Levoit Core 600S. It's best suited for medium-sized living rooms and dining areas and will likely struggle to operate effectively if you use it as a single unit in a large, open-concept apartment or living area.
This is an amazingly quiet air purifier. At its lowest fan speed, you can comfortably set it up in a bedroom or living room without worrying it'll disturb you while getting some shut-eye or watching TV. Even at its highest fan speed, it's far from a major nuisance, and most of its operating noise should be drowned out by nearby conversation.