Head to head

Alen BreatheSmart 75i Large Room Air Purifier vs Dyson Purifier Hot+Cool Formaldehyde HP09

Alen BreatheSmart 75i Large Room Air Purifier leads 4 to 1 on the 5 rankable specs and costs $50 less, which makes it the straightforward pick.

Catalog as of September 1, 2026

Why, in numbers

CADR: Alen BreatheSmart 75i Large Room Air Purifier lists 350 CFM across Smoke, Dust, Pollen (Alen sheet, 2026-09-02); Dyson Purifier Hot+Cool Formaldehyde HP09 lists 190 CFM class (Air Multiplier 77 gallons/sec circulation) (Dyson sheet, 2026-09-02).
Coverage area: Alen BreatheSmart 75i Large Room Air Purifier lists 1,400 sq ft (2 air changes/hr) / 700 sq ft (4 air changes/hr) (Alen sheet, 2026-09-02); Dyson Purifier Hot+Cool Formaldehyde HP09 lists 500 sq ft room size with 350° oscillation (Dyson sheet, 2026-09-02).
Room size: Alen BreatheSmart 75i Large Room Air Purifier lists Large master suites, open living rooms, offices (Alen sheet, 2026-09-02); Dyson Purifier Hot+Cool Formaldehyde HP09 lists Medium to large bedrooms, living rooms up to 500 sq ft (Dyson sheet, 2026-09-02).
Filter types: Alen BreatheSmart 75i Large Room Air Purifier lists Medical-grade H13 True HEPA + Antimicrobial layer + Heavy Odor Carbon (Alen sheet, 2026-09-02); Dyson Purifier Hot+Cool Formaldehyde HP09 lists 360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filter (Dyson sheet, 2026-09-02).
Filter life: Alen BreatheSmart 75i Large Room Air Purifier lists 12–15 months extra long filter life (Alen sheet, 2026-09-02); Dyson Purifier Hot+Cool Formaldehyde HP09 lists 12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst (Dyson sheet, 2026-09-02).

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

Alen BreatheSmart 75i Large Room Air Purifier

$7494 spec wins

Swap

Compare a different air purifier

Levoit Core 300S Smart True HEPA Air Purifier$149 Winix 5500-2 Air Purifier$159 Levoit Core 400S$219 Coway Airmega AP-1512HH Mighty$229 Blueair Blue Pure 311i Max$229 Honeywell HPA300 HEPA Air Purifier$249 Levoit Core 600S Smart True HEPA$299 Blueair Blue Pure 211+ Auto$339 Coway Airmega 250$399 Coway Airmega 400$549 Blueair Protect 7470i$649

Dyson Purifier Hot+Cool Formaldehyde HP09

$7991 spec win

Swap

Compare a different air purifier

Buying for

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

Straight answer

Overall: 4 to 1

Buy the Alen BreatheSmart 75i Large Room Air Purifier.

Leads 4 of 5 rankable overall specs; Dyson Purifier Hot+Cool Formaldehyde HP09 takes 1.
CADR: 350 CFM across Smoke, Dust, Pollen vs 190 CFM class
Coverage area: 1,400 sq ft vs 500 sq ft room size with 350° oscillation
It is also $50 cheaper.

Check first: the Alen BreatheSmart 75i Large Room Air Purifier weighs over 25 lb (11 kg). Tick them under deal-breakers if that rules it out.

4 Alen BreatheSmart 75i Large Room Air Purifier5 rankable of 11 specsDyson Purifier Hot+Cool Formaldehyde HP09 1

Deal-breakers

tick what would make you walk away

Over 55 dB on highrow
Louder than normal conversation at full speed.
Clear:Alen BreatheSmart 75i Large Room Air Purifier · 25 dB (WhisperMax) – 49 dB (Turbo speed)Trips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 46 dB (Low) – 62 dB (Max)
Under 1,000 sq ft coveragerow
Undersized for an open-plan living area.
Clear:Alen BreatheSmart 75i Large Room Air Purifier · 1,400 sq ftTrips:Dyson Purifier Hot+Cool Formaldehyde HP09 · 500 sq ft room size with 350° oscillati…
Over 25 lb (11 kg)row
Hard to move between rooms.
Trips:Alen BreatheSmart 75i Large Room Air Purifier · 27.0 lbClear:Dyson Purifier Hot+Cool Formaldehyde HP09 · 12.6 lb

At a glance

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

2 of 2 differ

CADR

Alen

350 CFM across Smoke, Dust, Pollen

Dyson

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

Coverage area

Alen

1,400 sq ft (2 air changes/hr) / 700 sq ft (4 air changes/hr)

Dyson

500 sq ft room size with 350° oscillation

True 3-Year Cost of Ownership (TCO)

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

⚠️ Cost Reversal Alert: While the Alen is cheaper upfront, the Dyson saves $7 over 3 years due to lower consumable & maintenance costs.

Alen BreatheSmart 75i Large Room Air Purifier

Upfront list price$749

3-Yr B6-Pure heavy HEPA filter (Every 12–15 months (~$99/yr))+$297

3-Year Estimated Total$1,046

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

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.

Alen

Requires 12 in perimeter airflow space

Dyson

Cylindrical base: needs 12 in airflow clearance around unit

Nighttime Sleep Mode Noise

Levels below 25 dB are virtually silent for light sleepers.

Alen

Standard sleep speed

Dyson

28 dB night mode with dimmed LCD

Unit Footprint & Dimensions

Alen

Standard room purifier footprint

Dyson

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

The 90-Day Owner Regret Check

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

Post-Purchase Truths

Alen: What to watch for

Maintenance
Requires periodic filter replacements to maintain airflow and odor capture.
Activated carbon and HEPA media gradually saturate, needing replacement once or twice yearly depending on air pollution and pet shedding.

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.

Alen BreatheSmart 75i Large Room Air Purifier$7494 wins

Dyson Purifier Hot+Cool Formaldehyde HP09$7991 win

Performance Filters Usability & Smart Design & Ownership

11 of 11 attributes differ. Identical rows are dimmed.

Performance

leads 2-0

Performance specifications. Middle column is Alen BreatheSmart 75i Large Room Air Purifier, right column is Dyson Purifier Hot+Cool Formaldehyde HP09.
CADR	350 CFM across Smoke, Dust, Pollen (wins this row: higher)	190 CFM class (Air Multiplier 77 gallons/sec circulation)
Room size	Large master suites, open living rooms, offices	Medium to large bedrooms, living rooms up to 500 sq ft
Coverage area	1,400 sq ft (2 air changes/hr) / 700 sq ft (4 air changes/hr) (wins this row: higher)	500 sq ft room size with 350° oscillation

Filters

leads 1-0

Filters specifications. Middle column is Alen BreatheSmart 75i Large Room Air Purifier, right column is Dyson Purifier Hot+Cool Formaldehyde HP09.
Filter types	Medical-grade H13 True HEPA + Antimicrobial layer + Heavy Odor Carbon	360° Glass HEPA H13 + Activated Carbon + Cryptomic Formaldehyde filter
Filter life	12–15 months extra long filter life (wins this row: higher)	12 months (HEPA/Carbon) / Permanent Formaldehyde catalyst

Usability & Smart

leads 1-0

Usability & Smart specifications. Middle column is Alen BreatheSmart 75i Large Room Air Purifier, right column is Dyson Purifier Hot+Cool Formaldehyde HP09.
Noise levels	25 dB (WhisperMax) – 49 dB (Turbo speed) (wins this row: lower)	46 dB (Low) – 62 dB (Max)
Energy consumption	45 W (Energy Star certified)	40 W (Purifier mode) / 1,575 W (Heating mode)
Smart features	Alen Air App (Wi-Fi), auto modes, color ring status	MyDyson App, voice control via Alexa, Google Assistant, Siri Shortcuts
Air quality sensors	Laser air quality sensor detecting fine particle levels with 5 color rings	Solid-state formaldehyde sensor, PM2.5, PM10, VOC, NO2, Temperature, Humidity

Design & Ownership

leads 1-0

Design & Ownership specifications. Middle column is Alen BreatheSmart 75i Large Room Air Purifier, right column is Dyson Purifier Hot+Cool Formaldehyde HP09.
Weight	27.0 lb (12.2 kg)	12.6 lb (5.7 kg) (wins this row: lower)
Warranty	Lifetime warranty (with active filter subscription)	2 years

Most rows are from the official spec sheet. Marked rows are other published figures or our summary, not lab tests we ran.

Alen BreatheSmart 75i Large Room Air Purifier source Dyson Purifier Hot+Cool Formaldehyde HP09 source

Which one should you buy

Pick this one if

Alen BreatheSmart 75i Large Room Air Purifier

Commercial-grade quiet purifier cleaning up to 1,400 sq ft every 30 minutes with a lifetime warranty.

Industry-exclusive transferable Lifetime Warranty
Tuned pink noise frequencies promote deeper sleep on WhisperMax mode
Medical-grade H13 True HEPA filter lasts up to 15 months

What you give up

High initial investment
Tall tower profile

Full Alen BreatheSmart 75i Large Room Air Purifier specs →

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 →

Best for each use

Bedrooms

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

Tied on bedrooms. Alen BreatheSmart 75i Large Room Air Purifier is cheaper.

The 2 rankable bedrooms specs split 1 to 1.
Saves $50 at list price.

Big rooms & allergies

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

For big rooms & allergies, buy the Alen BreatheSmart 75i Large Room Air Purifier.

Leads 3 of 3 rankable big rooms & allergies specs.
CADR: 350 CFM across Smoke, Dust, Pollen vs 190 CFM class
Coverage area: 1,400 sq ft vs 500 sq ft room size with 350° oscillation
It is also $50 cheaper.

Low running cost

Cheap to own: filter life, power draw, warranty

Too close to call on low running cost from the spec sheets. Only filter life is rankable here.

Energy consumption: 45 W vs 40 W
Warranty: Lifetime warranty vs 2 years

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.

Alen BreatheSmart 75i Large Room Air Purifier spec sheet Dyson Purifier Hot+Cool Formaldehyde HP09 spec sheet

Manufacturer pages: Alen BreatheSmart 75i Large Room Air Purifier ↗ · Dyson Purifier Hot+Cool Formaldehyde HP09 ↗

Common questions

Which is cheaper, the Alen BreatheSmart 75i Large Room Air Purifier or the Dyson Purifier Hot+Cool Formaldehyde HP09?

Alen BreatheSmart 75i Large Room Air Purifier costs $50 less at list price.

What is the biggest catch with the Alen BreatheSmart 75i Large Room Air Purifier or Dyson Purifier Hot+Cool Formaldehyde HP09?

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 Alen BreatheSmart 75i Large Room Air Purifier or the Dyson Purifier Hot+Cool Formaldehyde HP09?

Tied on bedrooms. Alen BreatheSmart 75i Large Room Air Purifier is cheaper. The 2 rankable bedrooms specs split 1 to 1. Saves $50 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.

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