Winix 9800
AHAM verified
- Really cleans
- 513 sq ft47 m² 47 m²513 sq ft
- Box says
- 2,506 sq ft233 m² 4.9× overstated
- New filter
- 3–12 months
Blueair · Blue Pure 211i Max (3613111100)
Blueair Blue Pure 211i Max
Really cleansAHAM verified
662 sq ft61 m² 61 m²662 sq ft
At 4.8 air changes an hour with a 2.5 m ceiling
- Box says
- Quickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hourQuickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hour (301 m²) 4.9× overstated
- New filter
- Every 9 months
Blueair's largest Blue Pure, with a verified CADR, an air quality sensor and an app. Cleans a large open-plan ground floor.
Verdict
Who it's for
A lot of verified air from a fairly light cylinder. Use it where one purifier has to cover a big open-plan space. It has an air quality sensor, auto mode and app control.
Good
- CADR verified by AHAM
- Covers large open-plan spaces
- Air quality sensor and app control
Trade-offs
- Filter is a Blueair-only part
- Box headline is based on one air change an hour
Spec facts
Blueair Blue Pure 211i Max · Blue Pure 211i Max (3613111100)
- Really cleans
- 662 sq ft · 61 m²61 m² · 662 sq ftat 4.8 air changes an hour, 2.5 m ceiling
- Box claim
- Quickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hourQuickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hour (301 m²)4.9× overstated
- Maker’s claim: Blueair · checked 1 Nov 2026
- Filter
- Blue Pure 211i Max replacement filterParticle + activated carbon, washable fabric pre-filter. Replace every 9 months
- Maker’s claim: Blueair · checked 1 Nov 2026
Certified: measured in an independent lab for AHAM’s Verifide programme. Maker’s claim: the manufacturer’s own figure, not independently checked. Where figures come from
Running it
Filter and upkeep
- Replacement filter
- Blue Pure 211i Max replacement filter
- Type
- Particle + activated carbon, washable fabric pre-filter
- Replace every
- 9 months
- Power at top speed
- 46 W
A new filter every 9 months means 1.3 filters a year. At top speed it draws 46 W: 1.1 kWh if it ran flat out all day. Slower settings use less.
We have no Amazon link for this filter: the maker's page in the sources sells or lists it.
Source: Maker’s claim, Blueair, checked 1 Nov 2026
The box vs the maths
The box says 3,235 sq ft301 m². It really cleans 662 sq ft61 m².
To clean 3,235 sq ft301 m² it would only change the air in the room 1 time an hour. We size every purifier at 4.8 air changes an hour, the level AHAM's room-size guideline works out to.
The box gives two figures. The smaller one, the area it cleans every 12.5 minutes, is 4.8 air changes an hour and close to our figure. The one we show as the box claim is the bigger: the room it can change the air of once an hour.
739 m³/h smoke CADR ÷ (4.8 × 2.5 m ceiling) = 61.6 m² = 662.9 sq ft61.6 m²
Use the calculator for your exact room and ceiling, or read how we pick.
Drawn to scale: the box says “Quickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hour”, the purifier really cleans 662 sq ft, 4.9 times less.Drawn to scale: the box says “Quickly cleans 674 ft² every 12.5 minutes & 3,235 ft² in 1 hour”, the purifier really cleans 61 m², 4.9 times less.
Room sizes
Which rooms it fits
It suits 376 sq ft35 m² and 430 sq ft40 m² rooms best: there it has 52–74% more air than the room needs, so it needn't run flat out. At 645 sq ft60 m² it only just keeps up (1% to spare), so it would run near its top speed, usually its loudest (why we don’t list noise). In rooms of 322 sq ft30 m² or less it's more than twice the size needed; a smaller model does the job.
Under a 2.7 m ceiling it covers 613 sq ft, under 3 m 552 sq ftUnder a 2.7 m ceiling it covers 57 m², under 3 m 51 m², so with a 3 m ceiling it no longer covers 645 sq ft60 m² (why).
For an 861 sq ft room or bigger it's too small, although the box claims 3,235 sq ft: the For an 80 m² room or bigger it's too small, although the box claims 301 m²: the 861 sq ft80 m² page lists models that cover it. In an open-plan space, add up every area without a door between (how).
Alternatives
The Blueair Blue Pure 211i Max or one of these?
The certified models closest in size, and what is different about each, from the same kinds of source.
Cleans 513 sq ft, 149 sq ft lessCleans 47 m², 14 m² less. It has an ionizer you can switch off. It has a different filter schedule (every 3–12 months). 1.1 kg heavier.
Levoit EverestAir-P
AHAM verified
- Really cleans
- 539 sq ft50 m² 50 m²539 sq ft
- Box says
- 2,635 sq ft245 m² 4.9× overstated
- New filter
- 12–15 months
Cleans 539 sq ft, 123 sq ft lessCleans 50 m², 11 m² less. It goes longer between filters (every 12–15 months) and draws 70 W at top speed. 2 kg heavier.
Levoit Core 600S-P
AHAM verified
- Really cleans
- 595 sq ft55 m² 55 m²595 sq ft
- Box says
- 2,909 sq ft270 m² 4.9× overstated
- New filter
- 6–12 months
Cleans 595 sq ft, 67 sq ft lessCleans 55 m², 6 m² less. It has a different filter schedule (every 6–12 months). 1.1 kg lighter.
Sources
Where these numbers come from
- Certified AHAM Verifide directory: Blueair Blue Pure 211i Max (3613111100) · AHAM Verifide
- Maker’s claim Blueair Blue Pure 211i Max product page and specifications · Blueair
We don't test purifiers ourselves: every figure on this page is copied from these sources and was last checked on 1 Nov 2026. Spotted one that's wrong or out of date? Tell us and we'll fix it and change the date.