Dyson - Purifier Big+Quiet Formaldehyde vs Xiaomi - Mi Smart Air Purifier 4 Pro
Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Dyson - Purifier Big+Quiet Formaldehyde | Xiaomi - Mi Smart Air Purifier 4 Pro |
|---|---|---|
| Coverage | 100 m² | 60 m² |
| CADR | 640 m³/h | 500 m³/h |
| Min noise | 24 dB | 32 dB |
Between the Purifier Big+Quiet Formaldehyde and Mi Smart Air Purifier 4 Pro, the Purifier Big+Quiet Formaldehyde comes out ahead in coverage / cadr, while the Mi Smart Air Purifier 4 Pro wins on several specs. Overall, the Purifier Big+Quiet Formaldehyde scores 89.3 and the Mi Smart Air Purifier 4 Pro scores 76.7 on our Mars Score.
Which should you buy?
The Purifier Big+Quiet Formaldehyde is the clear pick on raw spec strength, leading by 12.6 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the Purifier Big+Quiet Formaldehyde if you care most about coverage / cadr. The biggest gaps in its favor are coverage, cadr, min noise. The single most decisive one: Coverage — 66.67% more. 100 m² vs 60 m².
The Mi Smart Air Purifier 4 Pro similarly does not carry a headline advantage on the popular specs — look at the full table for category-specific deltas.
Both ship with comparable true hepa h13+, activated carbon, so those specs do not separate the two — focus on the differences below.
Bottom line: the Purifier Big+Quiet Formaldehyde is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Which should you buy: Dyson - Purifier Big+Quiet Formaldehyde or Xiaomi - Mi Smart Air Purifier 4 Pro?
Dyson - Purifier Big+Quiet Formaldehyde leads the current Mars Score by 12.6 points.The more useful decision is the trade-off behind that result: compare cadr, coverage, min noise against the way you will actually use the product.
Choose Dyson - Purifier Big+Quiet Formaldehyde if…
Dyson - Purifier Big+Quiet Formaldehyde has the measurable edge on coverage m2, cadr m3h, noise db min.
Choose Xiaomi - Mi Smart Air Purifier 4 Pro if…
Xiaomi - Mi Smart Air Purifier 4 Pro does not lead a decisive measured field here, so choose it for price, ecosystem, design, or availability when those matter more to you.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Dyson - Purifier Big+Quiet Formaldehyde wins
- ▲Coverage — 66.67% more. 100 m² vs 60 m².
- ▲CADR — 28.00% more. 640 m³/h vs 500 m³/h.
- ▲Min noise — 8.00 dB less. 24 vs 32.
Why Xiaomi - Mi Smart Air Purifier 4 Pro wins
- No decisive advantages.
Spec comparison
Performance
| Spec | Dyson - Purifier Big+Quiet Formaldehyde | Xiaomi - Mi Smart Air Purifier 4 Pro |
|---|---|---|
| CADR | 640 m³/hlead | 500 m³/h |
| Coverage | 100 m²lead | 60 m² |
| True HEPA H13+ | true | true |
| Activated carbon | true | true |
Smart & Noise
| Spec | Dyson - Purifier Big+Quiet Formaldehyde | Xiaomi - Mi Smart Air Purifier 4 Pro |
|---|---|---|
| Min noise | 24 dBlead | 32 dB |
| Air quality sensor | true | true |
| Smart app | true | true |