Research basis: Desk research conducted 2026-09-23 (public web: manufacturer, retailers, independent review/test sites) plus attributed owner evidence. No hands-on testing was performed — nothing here is a first-hand test result. Research date: 2026-09-23

At a glance

Coway's new 2026 large-room model (successor positioning to the 400 line). Highest CADR in Coway's consumer range, advanced PM1/2.5/10 laser sensor, and three swappable filter formulations (Fresh Starter, Allergen+, VOC-oriented) — unusual modularity at this price.

Specifications

SpecValueBasis
CADRSmoke 439 CFM / dust 445 CFM / pollen 450 CFM (Amazon comparison lists dust 455 — minor listing variance)trustedreviews.com; cowaymega.com; Amazon comparison
Room coverage3,285 sq ft at 1 ACH; 1,643 at 2 ACHManufacturer
Filter3-in-1 vacuumable prefilter + HEPA + carbon; Fresh Starter / Allergen+ / VOC-oriented options; 12 monthscowaymega.com
Noise23–57 dBManufacturer/reviews
Power72 WManufacturer
Smart featuresAdvanced PM1/2.5/10 laser sensor; app/connectivity status — UNVERIFIED this round—
WarrantyStandard Coway terms — check listingUNVERIFIED

Pricing & total cost of ownership (dated 2026-09-23)

ItemFigureDated source
Unit price$499 USA RRP; $368.99 observed sale pricetrustedreviews.com; Amazon search result (https://www.amazon.com/dp/B07TVL3F3D/…) (incomplete source URL)
Airmega 450 replacement filter$109.00 (listed as $119.00; 25% off first subscription)cowaymega.com shop-all page, crawled 2026-09-23
Annual filter cost~$109/yr (12-month life)Derived
4-year TCO (filters only)$935 at RRP ($499 + 4×$109); $804.99 at observed sale priceDerived

Attributed complaints & failure modes

  • Loud at maximum power: the consistent reviewer complaint — high CADR comes with high-speed noise (trustedreviews.com).
  • As a 2026 model, long-term reliability and real-world filter-life data are thin — treat first-year ownership reports as early evidence.

Specialty-use notes (attributed, not our verdict)

  • The VOC-oriented filter option is a genuine differentiator for odor/chemical-sensitive buyers — manufacturer positioning; no independent VOC-removal trial found in the documented sample.
  • Reviewer positioning: large open-plan rooms where the 400S's smart features aren't needed.

Community / social pulse

  • UNVALIDATED on the social layer — Threads/Facebook discovery held for security review 2026-09-23; results pending (access limitation, not no-results).

Evidence gaps

  • No current measured head-to-head vs direct 2026 large-room peers (Levoit Core 600S, Blueair 211i Max, Winix T810) found in the documented sample (browser searches, 2026-09-23) — this is the residual gap (HouseFresh's current measured comparator covers only the mid-size class: Mighty2 vs Vital 200S vs 5510/5520).
  • App/voice-assistant support status: UNVERIFIED.

Sources (full, dated)