Summary
The Winix 9800 (C909 at Costco) is the brand’s most powerful consumer cylinder, pushing a hefty 323 CFM (Cubic Feet per Minute) while staying whisper-quiet at 26 dB in Sleep. Wi-Fi smarts, dual sensors, and once-a-year $80 filter kits make it a hands-off wildfire and allergy ally for bedrooms and living spaces up to about 400 ft²—just toggle PlasmaWave off for zero ozone.
Here's what this purifier does best
- High CADR (Clean Air Delivery Rate) per dollar: 323 CFM (Cubic Feet per Minute) at this price beats many smart rivals on cost-for-clean-air.
- Ultra-quiet Sleep mode: 26 dB (near-silent) keeps light sleepers comfortable.
- Pellet carbon panels: Better VOC and wildfire-odor capture than thin carbon sheets.
- Smart-app control: Wi-Fi, AQI (Air Quality Index) graphs, scheduling, and Alexa voice integration.
- Filter kit included for a year: Box ships with all carbon pads plus HEPA—no extra cost for 12 months.
Consider these trade-offs
- Coverage hype: “2,420 ft²” spec assumes 1 ACH (Air Changes per Hour)—real health coverage tops out near 400 ft².
- Ionizer default-on: PlasmaWave adds trace ozone (<5 ppb); must be turned off for the ultra-sensitive.
- Bonded carbon → full-kit swap: Can’t change only the odor layer; whole $80 cartridge each year.
- Mid-50 dB on Turbo: Noticeable fan roar during heavy smoke events.
- No carry handle or wheels: 18-lb tower is awkward to move frequently.