Skip to content
Clinchmark

Head to head

Dyson Purifier Hot+Cool Formaldehyde HP09 vs Blueair Blue Pure 311i Max

Blueair Blue Pure 311i Max leads 3 to 1 on the 4 rankable specs and costs $570 less, which makes it the straightforward pick. Most of the 11 attributes tracked here are descriptive rather than numeric.

Catalog as of September 1, 2026

Why, in numbers

  • CADR: Dyson Purifier Hot+Cool Formaldehyde HP09 lists 190 CFM class (Air Multiplier 77 gallons/sec circulation) (Dyson sheet, 2026-09-02); Blueair Blue Pure 311i Max lists 250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen) (Blueair sheet, 2026-09-02).
  • Coverage area: Dyson Purifier Hot+Cool Formaldehyde HP09 lists 500 sq ft room size with 350° oscillation (Dyson sheet, 2026-09-02); Blueair Blue Pure 311i Max lists 387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr) (Blueair sheet, 2026-09-02).
  • Room size: Dyson Purifier Hot+Cool Formaldehyde HP09 lists Medium to large bedrooms, living rooms up to 500 sq ft (Dyson sheet, 2026-09-02); Blueair Blue Pure 311i Max lists Medium to large bedrooms, living rooms, and open offices up to 387 sq ft (4.8 ACH) / 929 sq ft (2 ACH) (Blueair sheet, 2026-09-02).
  • Filter types: Dyson Purifier Hot+Cool Formaldehyde HP09 lists 360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filter (Dyson sheet, 2026-09-02); Blueair Blue Pure 311i Max lists HEPASilent Main Particle + Carbon filter with customizable machine-washable fabric pre-filter (Blueair sheet, 2026-09-02).
  • Filter life: Dyson Purifier Hot+Cool Formaldehyde HP09 lists 12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst (Dyson sheet, 2026-09-02); Blueair Blue Pure 311i Max lists 6 to 9 months (tracked by RealTrack algorithm in app) (Blueair sheet, 2026-09-02).

Manufacturer list price, not a live offer. Confirm current pricing before you buy.

Dyson Purifier Hot+Cool Formaldehyde HP09
$7991 spec win
Swap

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$229Honeywell HPA300 HEPA Air Purifier$249Levoit Core 600S Smart True HEPA$299Blueair Blue Pure 211+ Auto$339Coway Airmega 250$399Coway Airmega 400$549Blueair Protect 7470i$649Alen BreatheSmart 75i Large Room Air Purifier$749
Blueair Blue Pure 311i Max
$2293 spec wins
Swap

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$229Honeywell HPA300 HEPA Air Purifier$249Levoit Core 600S Smart True HEPA$299Blueair Blue Pure 211+ Auto$339Coway Airmega 250$399Coway Airmega 400$549Blueair Protect 7470i$649Alen BreatheSmart 75i Large Room Air Purifier$749

Buying for

Every rankable spec counts once. Pick a lens to score only what matters for your air purifier.

Straight answer

Overall: 1 to 3

Buy the Blueair Blue Pure 311i Max.

  • Leads 3 of 4 rankable overall specs; Dyson Purifier Hot+Cool Formaldehyde HP09 takes 1.
  • CADR: 250 CFM vs 190 CFM class
  • Noise levels: 23 dB vs 46 dB
  • It is also $570 cheaper.
1 Dyson Purifier Hot+Cool Formaldehyde HP094 rankable of 11 specsBlueair Blue Pure 311i Max 3

Deal-breakers

tick what would make you walk away

  • row

    Louder than normal conversation at full speed.

    Trips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 46 dB (Low) – 62 dB (Max)Clear:Blueair Blue Pure 311i Max · 23 dB (Night mode) – 50 dB (Max boost)
  • row

    Undersized for an open-plan living area.

    Trips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 500 sq ft room size with 350° oscillati…Trips:Blueair Blue Pure 311i Max · 387 sq ft

At a glance

The handful of numbers that decide most purchases in this category.

2 of 2 differ

CADR

Dyson

190 CFM class (Air Multiplier 77 gallons/sec circulation)

Blueair

250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen)

Coverage area

Dyson

500 sq ft room size with 350° oscillation

Blueair

387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr)

True 3-Year Cost of Ownership (TCO)

Upfront price + 3 years of consumables, fees & essential add-ons

Dyson Purifier Hot+Cool Formaldehyde HP09

Upfront list price$799
3-Yr 360° Combi Glass HEPA + Carbon (Every 12 months (~$80/yr))+$240
3-Year Estimated Total$1,039

Blueair Blue Pure 311i Max

Upfront list price$229
3-Yr SmokeBlock combo filter (Every 6–9 months (~$35/yr))+$105
3-Year Estimated Total$334

Room Placement & Bedroom Noise Check

Physical clearance required for airflow, wall placement, and bedroom noise levels.

Ergonomic & Spatial Check

Wall Clearance Required

Cylindrical 360° filters cannot sit flush against walls without choking intake.

Dyson

Cylindrical base: needs 12 in airflow clearance around unit

Blueair

360° fabric pre-filter intake (needs 12 in wall space)

Nighttime Sleep Mode Noise

Levels below 25 dB are virtually silent for light sleepers.

Dyson

28 dB night mode with dimmed LCD

Blueair

23 dB lowest speed setting

Unit Footprint & Dimensions

Dyson

Bladeless oval loop (30.0 × 8.1 × 8.1 in; 12.6 lb; heats & cools)

Blueair

Cylindrical aesthetic (12.4 × 12.4 × 18.9 in; 7.8 lb)

The 90-Day Owner Regret Check

Documented ergonomic quirks, hardware annoyances, and maintenance realities reported by real owners.

Post-Purchase Truths

Dyson: What to watch for

  • Hidden Cost

    High replacement filter cost (~$80 each).

    The catalytic formaldehyde combo filter is significantly more expensive than standard box purifiers from Levoit or Coway.

Blueair: What to watch for

  • Maintenance

    Outer fabric pre-filter attracts visible pet fur and lint.

    The decorative fabric outer sleeve functions as the coarse pre-filter, requiring weekly vacuuming to avoid looking dusty in living rooms.

Dyson Purifier Hot+Cool Formaldehyde HP09$7991 win
Blueair Blue Pure 311i Max$2293 wins

Performance

3 differences
Performance specifications. Middle column is Dyson Purifier Hot+Cool Formaldehyde HP09, right column is Blueair Blue Pure 311i Max.
CADR190 CFM class (Air Multiplier 77 gallons/sec circulation)250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen) (wins this row: higher)
Room sizeMedium to large bedrooms, living rooms up to 500 sq ftMedium to large bedrooms, living rooms, and open offices up to 387 sq ft (4.8 ACH) / 929 sq ft (2 ACH)
Coverage area500 sq ft room size with 350° oscillation (wins this row: higher)387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr)

Filters

2 differences
Filters specifications. Middle column is Dyson Purifier Hot+Cool Formaldehyde HP09, right column is Blueair Blue Pure 311i Max.
Filter types360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filterHEPASilent Main Particle + Carbon filter with customizable machine-washable fabric pre-filter
Filter life12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst6 to 9 months (tracked by RealTrack algorithm in app)

Usability & Smart

leads 1-0
Usability & Smart specifications. Middle column is Dyson Purifier Hot+Cool Formaldehyde HP09, right column is Blueair Blue Pure 311i Max.
Noise levels46 dB (Low) – 62 dB (Max)23 dB (Night mode) – 50 dB (Max boost) (wins this row: lower)
Energy consumption40 W (Purifier mode) / 1,575 W (Heating mode)38 W max power consumption (Energy Star Most Efficient)
Smart featuresMyDyson App, voice control via Alexa, Google Assistant, Siri ShortcutsBlueair App (iOS/Android), voice control with Amazon Alexa and Google Assistant, geofencing Welcome Home feature
Air quality sensorsSolid-state formaldehyde sensor, PM2.5, PM10, VOC, NO2, Temperature, HumidityLaser particle sensor with 5-color LED air quality indicator ring (PM1, PM2.5, PM10)

Design & Ownership

leads 1-0
Design & Ownership specifications. Middle column is Dyson Purifier Hot+Cool Formaldehyde HP09, right column is Blueair Blue Pure 311i Max.
Weight12.6 lb (5.7 kg)7.8 lb (3.5 kg) (wins this row: lower)
Warranty2 years2 years limited warranty (extendable to 3 years with product registration)
Most rows are from the official spec sheet. Marked rows are other published figures or our summary, not lab tests we ran.
Dyson Purifier Hot+Cool Formaldehyde HP09 source (opens in a new tab)Blueair Blue Pure 311i Max source (opens in a new tab)

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
Full Dyson Purifier Hot+Cool Formaldehyde HP09 specs →

Pick this one if

Blueair Blue Pure 311i Max

Smart air purifier with HEPASilent dual filtration technology, cleaning up to 929 sq ft in 30 minutes, 23dB whisper quiet operation, and Blueair app control.

  • HEPASilent dual filtration combines electrostatic and mechanical filtration for faster airflow at lower noise
  • Cleans up to 387 sq ft in 12.5 minutes (4.8 ACH) / up to 929 sq ft in 30 minutes (2 ACH)
  • Ultra-quiet 23dB Night Mode with Energy Star certified low electricity draw

What you give up

  • Fabric pre-filter covers the exterior and requires periodic vacuuming/washing
  • Filter replacements needed every 6 to 9 months
Full Blueair Blue Pure 311i Max specs →

Best for each use

Bedrooms

Quiet nights: low-speed noise, sleep mode, schedules from your phone

For bedrooms, buy the Blueair Blue Pure 311i Max.

  • Leads 2 of 2 rankable bedrooms specs.
  • Noise levels: 23 dB vs 46 dB
  • Weight: 7.8 lb vs 12.6 lb
  • It is also $570 cheaper.

Big rooms & allergies

Open-plan rooms or allergies: CADR, coverage, filter grade

Tied on big rooms & allergies. Blueair Blue Pure 311i Max is cheaper.

  • The 2 rankable big rooms & allergies specs split 1 to 1.
  • Saves $570 at list price.

Low running cost

Cheap to own: filter life, power draw, warranty

Too close to call on low running cost from the spec sheets.

  • Filter life: 12 months vs 6 to 9 months
  • Energy consumption: 40 W vs 38 W max power consumption

Every answer above is scored from published figures. A lens uses only the rows that matter for that use, including marked rows that are not on the official sheet. Switch lenses interactively in the panel above.

Done deciding?

Open the full standalone spec sheet for either device.

Dyson Purifier Hot+Cool Formaldehyde HP09 spec sheetBlueair Blue Pure 311i Max spec sheet

Manufacturer pages: Dyson Purifier Hot+Cool Formaldehyde HP09 ↗ · Blueair Blue Pure 311i Max ↗

Common questions

Which is cheaper, the Dyson Purifier Hot+Cool Formaldehyde HP09 or the Blueair Blue Pure 311i Max?

Blueair Blue Pure 311i Max costs $570 less at list price.

What is the biggest catch with the Dyson Purifier Hot+Cool Formaldehyde HP09 or Blueair Blue Pure 311i Max?

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 Blueair Blue Pure 311i Max?

For bedrooms, buy the Blueair Blue Pure 311i Max. Leads 2 of 2 rankable bedrooms specs. Noise levels: 23 dB vs 46 dB

What cannot be compared from spec sheets?

Of the 11 specs tracked here, 7 are descriptive and cannot be ranked on numbers alone. Spec sheets also cannot measure subjective factors like build quality, real-world performance, or comfort.

Other matchups

Alen BreatheSmart 75i Large Room Air Purifier vs Blueair Blue Pure 211+ Auto

Alen BreatheSmart 75i Large Room Air Purifier vs Blueair Blue Pure 311i Max

Alen BreatheSmart 75i Large Room Air Purifier vs Blueair Protect 7470i