Head to head
Dyson Purifier Hot+Cool Formaldehyde HP09 vs Coway Airmega 250
Coway Airmega 250 leads 4 to 1 on the 5 rankable specs and costs $400 less, which makes it the straightforward pick.
Catalog as of September 1, 2026
Why, in numbers
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Compare a different air purifier
Levoit Core 300S Smart True HEPA Air Purifier$149Winix 5500-2 Air Purifier$159Levoit Core 400S$219Coway Airmega AP-1512HH Mighty$229Blueair Blue Pure 311i Max$229Honeywell HPA300 HEPA Air Purifier$249Levoit Core 600S Smart True HEPA$299Blueair Blue Pure 211+ Auto$339Coway Airmega 400$549Blueair Protect 7470i$649Alen BreatheSmart 75i Large Room Air Purifier$749Buying for
Straight answer
Overall: 1 to 4
Buy the Coway Airmega 250.
- Leads 4 of 5 rankable overall specs; Dyson Purifier Hot+Cool Formaldehyde HP09 takes 1.
- CADR: 249 CFM vs 190 CFM class
- Coverage area: 930 sq ft vs 500 sq ft room size with 350° oscillation
- It is also $400 cheaper.
Deal-breakers
tick what would make you walk away
- Trips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 46 dB (Low) – 62 dB (Max)Clear:Coway Airmega 250 · 22 dB (Sleep mode) – 54 dB (Max speed)
- Trips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 500 sq ft room size with 350° oscillati…Trips:Coway Airmega 250 · 930 sq ft
At a glance
The handful of numbers that decide most purchases in this category.
CADR
Dyson
190 CFM class (Air Multiplier 77 gallons/sec circulation)
Coway
249 CFM (Smoke), 261 CFM (Dust), 230 CFM (Pollen)
Coverage area
Dyson
500 sq ft room size with 350° oscillation
Coway
930 sq ft (2 air changes/hr) / 465 sq ft (4 air changes/hr)
True 3-Year Cost of Ownership (TCO)
Dyson Purifier Hot+Cool Formaldehyde HP09
Coway Airmega 250
Room Placement & Bedroom Noise Check
Physical clearance required for airflow, wall placement, and bedroom noise levels.
Wall Clearance Required
Cylindrical base: needs 12 in airflow clearance around unit
Bottom & dual-side intake: sits flush against back wall
Nighttime Sleep Mode Noise
28 dB night mode with dimmed LCD
22 dB sleep mode with auto-dimming LED light sensor
Unit Footprint & Dimensions
Bladeless oval loop (30.0 × 8.1 × 8.1 in; 12.6 lb; heats & cools)
Modern slim tower (19.7 × 18.5 × 8.3 in; 20.5 lb)
The 90-Day Owner Regret Check
Documented ergonomic quirks, hardware annoyances, and maintenance realities reported by real owners.
Dyson: What to watch for
- Hidden Cost
High replacement filter cost (~$80 each).
Coway: What to watch for
- Maintenance
Requires periodic filter replacements to maintain airflow and odor capture.
Performance
leads 2-0| CADR | 190 CFM class (Air Multiplier 77 gallons/sec circulation) | 249 CFM (Smoke), 261 CFM (Dust), 230 CFM (Pollen) (wins this row: higher) |
|---|---|---|
| Room size | Medium to large bedrooms, living rooms up to 500 sq ft | Large bedrooms, apartments, living rooms, and open layouts up to 930 sq ft |
| Coverage area | 500 sq ft room size with 350° oscillation | 930 sq ft (2 air changes/hr) / 465 sq ft (4 air changes/hr) (wins this row: higher) |
Filters
2 differences| Filter types | 360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filter | EZ-clean Washable Pre-filter + Max2 Green True HEPA and Activated Carbon filter |
|---|---|---|
| Filter life | 12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst | 12 months (Max2 filter) / Washable slide-out pre-filter |
Usability & Smart
leads 1-0| Noise levels | 46 dB (Low) – 62 dB (Max) | 22 dB (Sleep mode) – 54 dB (Max speed) (wins this row: lower) |
|---|---|---|
| Energy consumption | 40 W (Purifier mode) / 1,575 W (Heating mode) | 60 W max power consumption (Energy Star Certified) |
| Smart features | MyDyson App, voice control via Alexa, Google Assistant, Siri Shortcuts | Smart Auto Mode, Rapid Mode, Eco Mode, and Sleep Mode |
| Air quality sensors | Solid-state formaldehyde sensor, PM2.5, PM10, VOC, NO2, Temperature, Humidity | Real-time particle sensor with colorful LED air quality indicator |
Design & Ownership
2 differences| Weight | 12.6 lb (5.7 kg) (wins this row: lower) | 20.5 lb (9.3 kg) |
|---|---|---|
| Warranty | 2 years | 5 years limited warranty on motor / 1 year electronic parts (wins this row: higher) |
Which one should you buy
Pick this one if
Dyson Purifier Hot+Cool Formaldehyde HP09
3-in-1 purifier, ceramic space heater, and cooling fan with solid-state catalytic formaldehyde sensor.
- Combines HEPA H13 purification, fast ceramic heating, and cooling fan in one
- Destroys formaldehyde continuously without filter replacement
- Fully sealed whole-machine HEPA H13 standard prevents bypass
What you give up
- CADR airflow is lower than dedicated box purifiers
- Expensive upfront purchase price
Pick this one if
Coway Airmega 250
Modern slim aesthetic air purifier with Green True HEPA Max2 filtration, covering up to 930 sq ft, Smart Auto mode, and easy-clean washable pre-filter.
- Green True HEPA filter captures 99.999% of 0.01-micron ultrafine particles and neutralizes odors
- Easy-to-clean EZ-pull front pre-filter slides out from the top without opening the machine
- Covers up to 930 sq ft with Smart Auto Mode and real-time PM2.5 particle sensor LED ring
What you give up
- No Wi-Fi app connectivity on the standard 250 model (app available on 250S variant)
- Substantial 20.5 lb weight
Best for each use
Bedrooms
Tied on bedrooms. Coway Airmega 250 is cheaper.
Big rooms & allergies
For big rooms & allergies, buy the Coway Airmega 250.
Low running cost
Too close to call on low running cost from the spec sheets. Only warranty is rankable here.
Done deciding?
Open the full standalone spec sheet for either device.
Manufacturer pages: Dyson Purifier Hot+Cool Formaldehyde HP09 ↗ · Coway Airmega 250 ↗
Common questions
Which is cheaper, the Dyson Purifier Hot+Cool Formaldehyde HP09 or the Coway Airmega 250?
Coway Airmega 250 costs $400 less at list price.
What is the biggest catch with the Dyson Purifier Hot+Cool Formaldehyde HP09 or Coway Airmega 250?
Dyson Purifier Hot+Cool Formaldehyde HP09 has this deal-breaker: over 55 dB on high. Louder than normal conversation at full speed.
Which is better for bedrooms, the Dyson Purifier Hot+Cool Formaldehyde HP09 or the Coway Airmega 250?
Tied on bedrooms. Coway Airmega 250 is cheaper. The 2 rankable bedrooms specs split 1 to 1. Saves $400 at list price.
What cannot be compared from spec sheets?
Of the 11 specs tracked here, 6 are descriptive and cannot be ranked on numbers alone. Spec sheets also cannot measure subjective factors like build quality, real-world performance, or comfort.