Dyson
Dyson Purifier Hot+Cool Formaldehyde HP09
Air purifiers
$799List price
Explore this product Your shortlist, side by side
Dyson Purifier Hot+Cool Formaldehyde HP09 vs Blueair Blue Pure 311i Max
Find the differences that matter for your next decision.
Blueair
Blueair Blue Pure 311i Max
Air purifiers
$229List price
Explore this product What matters most to you?
Start with all rankable specifications, or focus on a particular use.
Your starting point
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
How we reached this
We compare the published specifications relevant to your priority. Each rankable specification counts once; your selected requirements can rule a product out. This is a guide to the numbers, not a laboratory performance score.
Noise levels: 23 dB vs 46 dB
It is also $570 cheaper.
The trade-off to know
Blueair Blue Pure 311i Max: Fabric pre-filter covers the exterior and requires periodic vacuuming/washing
Look at the differences ↓Refine your requirements
What would rule one out?
Side by side
The differences, in detail.
Start with the key specs, then explore as much as you need.
| What you’re comparing | Dyson Purifier Hot+Cool Formaldehyde HP09 | Blueair Blue Pure 311i Max |
|---|---|---|
| CADRPerformance | 190 CFM class (Air Multiplier 77 gallons/sec circulation) | 250 CFM (Smoke), 250 CFM (Dust), 250 CFM (Pollen) |
| Room sizePerformance | Medium to large bedrooms, living rooms up to 500 sq ft | Medium to large bedrooms, living rooms, and open offices up to 387 sq ft (4.8 ACH) / 929 sq ft (2 ACH) |
| Coverage areaPerformance | 500 sq ft room size with 350° oscillation | 387 sq ft (4.8 air changes/hr) / 929 sq ft (2 air changes/hr) |
| Filter typesFilters | 360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filter | HEPASilent Main Particle + Carbon filter with customizable machine-washable fabric pre-filter |
| Filter lifeFilters | 12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst | 6 to 9 months (tracked by RealTrack algorithm in app) |
Showing 5 of 11 specifications. Missing values stay unlisted. About the sources
Both sides of the decision
What you gain. What you give up.
Dyson Purifier Hot+Cool Formaldehyde HP09
Reasons to choose it
- 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
Worth considering
- CADR airflow is lower than dedicated box purifiers
- Expensive upfront purchase price
Blueair Blue Pure 311i Max
Reasons to choose it
- 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
Worth considering
- Fabric pre-filter covers the exterior and requires periodic vacuuming/washing
- Filter replacements needed every 6 to 9 months
Beyond the spec sheet
Living with your choice.
Explore the ownership details available for this pair.
What three years could cost
Dyson Purifier Hot+Cool Formaldehyde HP09
3-Year Estimated Total$1,039
Blueair Blue Pure 311i Max
3-Year Estimated Total$334
Room Placement & Bedroom Noise Check
Physical clearance required for airflow, wall placement, and bedroom noise levels.
Wall Clearance Required
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
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)
Everyday ownership notes
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).
Blueair: What to watch for
- Maintenance
Outer fabric pre-filter attracts visible pet fur and lint.
Know what’s behind the comparison
Published specs. Visible sources.
Clinchmark compares manufacturer specifications and other published information. We have not independently lab-tested these products. Editorial assessments and unknown values are identified in the specification details.
Catalog snapshot: September 1, 2026. Prices, availability, and provider terms can change.
Still weighing it up?
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.