Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Winix - 5500-2 | Winix - C909 |
|---|---|---|
| Coverage | 33 m² | 50 m² |
| CADR | 415 m³/h | 500 m³/h |
| True HEPA H13+ | false | true |
Between the 5500-2 and C909, the 5500-2 comes out ahead in several specs, while the C909 wins on coverage / cadr. Overall, the 5500-2 scores 60.1 and the C909 scores 77.7 on our Mars Score.
Which should you buy?
The C909 is the clear pick on raw spec strength, leading by 17.6 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.
The 5500-2 does not pull ahead on any single popular-comparison spec — its strengths sit in the spec-table groups rather than the headline advantages.
Pick the C909 if you care most about coverage / cadr. Its strongest claims are coverage, cadr, true hepa h13+. The single most decisive one: Coverage — 51.52% more. 50 m² vs 33 m².
Both ship with comparable activated carbon, min noise, so those specs do not separate the two — focus on the differences below.
Bottom line: the C909 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: Winix - 5500-2 or Winix - C909?
Winix - C909 leads the current Mars Score by 17.6 points.The more useful decision is the trade-off behind that result: compare cadr, coverage, true hepa h13+ against the way you will actually use the product.
Choose Winix - 5500-2 if…
Winix - 5500-2 does not lead a decisive measured field here, so choose it for price, ecosystem, design, or availability when those matter more to you.
Choose Winix - C909 if…
Winix - C909 has the measurable edge on coverage m2, cadr m3h, has hepa 13.
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 Winix - 5500-2 wins
- No decisive advantages.
Why Winix - C909 wins
- ▲Coverage — 51.52% more. 50 m² vs 33 m².
- ▲CADR — 20.48% more. 500 m³/h vs 415 m³/h.
- ▲Has True HEPA H13+.
Spec comparison
Performance
| Spec | Winix - 5500-2 | Winix - C909 |
|---|---|---|
| CADR | 415 m³/h | 500 m³/hlead |
| Coverage | 33 m² | 50 m²lead |
| True HEPA H13+ | false | truelead |
| Activated carbon | true | true |
Smart & Noise
| Spec | Winix - 5500-2 | Winix - C909 |
|---|---|---|
| Min noise | 27 dB | 27 dB |
| Air quality sensor | true | true |
| Smart app | false | truelead |