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Blueair Blue Pure 311i Max

By the NestyFinds editorial team · Researched from manufacturer documentation, manuals and the AHAM Verifide directory · not bench-tested

439 ft² CADR 283 cfm AHAM Verifide CARB certified Filter ~9 mo 23–50 dB

AHAM Verifide at 283 cfm smoke for a 439 sq ft room, and the rare case where the electrostatic question has an actual number attached: ENERGY STAR measured its ozone emission at 2 ppb.

Blueair Blue Pure 311i Max

Pros

  • A full AHAM Verifide CADR set — 314 dust, 283 smoke, 365 pollen — and Blueair prints those exact numbers on its own page instead of a rounder marketing figure.
  • The 439 sq ft room size reconciles from three directions: AHAM's directory, AHAM's own formula, and the ENERGY STAR record.
  • Blueair states the air-change basis in plain words — four changes every 12.5 minutes — rather than quoting a big room size and leaving you to guess what it means.
  • The electrostatic question has a measured answer here: 2.00 ppb of ozone in the ENERGY STAR record, against 0.00 for the mechanical machines in the same list. Most brands leave this to adjectives.
  • ENERGY STAR certified with an integrated energy factor of 8.4 cfm per watt, which is high for this catalogue, at 193 kWh a year.
  • Auto mode runs from a real air-quality sensor, and the filter-life counter uses measured pollution rather than elapsed days.

Cons

  • ⚠️ THE FILTER PAGE FOR THIS MACHINE CARRIES THE WRONG COMPATIBILITY LINE. Blueair's page for the 311i Max filter says, in its one compatibility sentence, that it fits the 311i+ Max — the other machine. The two are different parts with different SKUs and different barcodes. Order by SKU 110037 or UPC 689122023298 and ignore the sentence.
  • CARB classifies it Electronic, and on HEPASilent the charging stage is integral rather than a feature you can switch off. If you want a filtration-only machine, this is not one.
  • Blueair does not name the four filtration layers individually on the product page, so what the "4 layers" are is not documented there.
  • ⚠️ The 311i Max and the 311i+ Max are different machines, not trim levels: AHAM measures them at 283 and 339 cfm smoke, across 439 and 525 sq ft. The names differ by one character and the filters differ by one digit of SKU.
  • ENERGY STAR records the filter type as "HEPA-Type", which is a weaker value in that programme's own taxonomy than the H13 grade some competitors declare.
  • The bigger coverage figures you will see quoted — 1,054 and 2,107 sq ft — are the same machine at fewer air changes per hour, and are not comparable with a 4.8 ACH number.

Our editorial rating, not a lab measurement. Weighed independent measurement above manufacturer claims, and this model is corroborated twice over — AHAM and ENERGY STAR record the same CADR set and the same room size that Blueair publishes. Documentation is unusually complete: noise range, wattage, dimensions, weight, energy factor, annual consumption and a measured ozone emission. Against it: a CARB Electronic classification with a charging stage that cannot be switched off, a filter page whose compatibility line names the wrong machine, four filtration layers Blueair declines to name, and a filter grade recorded as HEPA-Type rather than a declared H13.

Verdict

The Blue Pure 311i Max is one of the better-documented machines in this catalogue. AHAM measures it at 283 cfm smoke and sizes it at 439 sq ft; Blueair publishes those same numbers and, unusually, explains the air-change basis behind them; and the ENERGY STAR list independently records the same room size and CADR set. The thing that makes this page worth reading is the ozone figure. CARB classifies the machine Electronic because HEPASilent charges particles before filtering them, and that classification usually leaves a buyer with nothing but adjectives. Here there is a number: 2.00 ppb in the ENERGY STAR record, against 0.00 for the mechanical machines in the same list. Small, measured, and yours to weigh. One practical warning: Blueair's own filter page for this machine carries a compatibility line naming the other model, so order the consumable by SKU or barcode rather than by that sentence.

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Is it the right one for you?

Who it's for

  • A living room, bedroom or open-plan space of roughly 439 sq ft at a genuine 4.8 air changes an hour.
  • Anyone who wants the machine to run itself from a sensor and to count filter life by what it actually measured rather than by the calendar.
  • People who would rather read a measured ozone figure and decide for themselves than be told a machine is "safe".
  • Anyone weighing running cost: 193 kWh a year and 8.4 cfm per watt are both documented rather than estimated.

Who should skip it

  • Anyone who wants a purely mechanical machine. Every Blueair in this catalogue is CARB Electronic, and on HEPASilent that is not optional.
  • Rooms materially larger than 439 sq ft, unless you accept fewer air changes than AHAM's basis.
  • Anyone who wants a declared H13 filtration grade: the ENERGY STAR record files this one as HEPA-Type.

Specifications

How this coverage figure is stated

4.8 air changes per hour, and three separate bodies print the same number. AHAM's directory gives 439 sq ft. AHAM's own rule is room size = smoke CADR x 1.55, and 283 x 1.55 = 438.65. The ENERGY STAR certified-products list records room size 439 sq ft for this model. Blueair itself says "Quickly cleans 439 ft² in 12.5 minutes" and explains the basis as the AHAM recommendation of four air changes every 12.5 minutes. The larger figures on the page — 1,054 sq ft in 30 minutes, 2,107 sq ft in an hour — are the same machine measured at fewer air changes, not extra capability.

Always compare two purifiers at the same air-change rate; manufacturers pick different ones and the headline square footage is not otherwise comparable.

Blueair Blue Pure 311i Max — documented specifications
Smoke CADR 283 cfm, AHAM Verifide and Blueair's own page states the same 283
AHAM suggested room size 439 sq ft, equivalent to 4.8 air changes per hour
CARB Certified, device type Electronic, notified 2023-03-09, executive order G-23-050
Noise 23–50 dB
Power 32 W stated by Blueair AHAM recorded 29.6 operating watts during its smoke test
Filter life Up to 9 months calculated by Blueair's RealTrack algorithm rather than by the calendar
Replacement filter F3MAX for the 311i Max SKU 110037, UPC 689122023298. See the warning below before ordering
The full record: 9 more documented specifications — nothing is removed, it is just not what decides
Dust CADR 314 cfm, AHAM Verifide
Pollen CADR 365 cfm, AHAM Verifide its strongest measured figure
PM2.5 CADR 298 cfm, recorded by both AHAM and ENERGY STAR
Measured ozone emission 2.00 ppb, from the ENERGY STAR certified-products list
ENERGY STAR Certified 2023-03-08; integrated energy factor 8.4 cfm/W; 193 kWh per year. Not flagged Most Efficient the larger 311i+ Max is
Dimensions 19 x 12.5 x 12.5 in
Weight 7.8 lb
Filter indicator reset Hold the fan speed button about 15 seconds until all the interface LEDs light
Machine UPC 689122023021, per the ENERGY STAR record
8 things we could not verify — we leave these blank rather than estimate them
  • THE AHAM FIGURES HERE WERE READ IN THE DIRECTORY'S OWN INTERFACE at ahamdir.com on 14 September 2026, not taken from a data dump. AHAM's printed 2023 edition is a snapshot and does not carry every model in the live directory.
  • ⚠️ THE AHAM COLUMN ORDER IS DUST FIRST, THEN TOBACCO SMOKE, THEN POLLEN. The printed directory's own header reads "Dust CADR | Tobacco Smoke CADR | Pollen CADR | Room Size sq FT | Meet Ozone Limits", and the live directory labels the same fields explicitly. Reading the first column as smoke would publish the wrong headline figure and a room size that does not reconcile.
  • ⚠️ THE WRONG COMPATIBILITY LINE WAS VERIFIED IN THE PAGE'S RAW HTML, NOT INFERRED FROM A SUMMARY. Blueair's page for the 311i Max filter mentions "311i Max" 65 times and "311i+" exactly once — and that single occurrence is the compatibility sentence, "This filter is compatible only with the Blue Pure Max 311i+ air purifier". The neighbouring page, for the 311i+ Max filter, carries the identical sentence and mentions "311i+" 60 times. The line appears to have been copied between the two.
  • THE TWO FILTERS ARE DIFFERENT PARTS, WHICH IS HOW WE KNOW THE LINE IS WRONG RATHER THAN THE MACHINES BEING INTERCHANGEABLE. The 311i Max filter carries SKU 110037 and UPC 689122023298; the 311i+ Max filter carries SKU 110038 and UPC 689122023304. Whether the two cartridges are nonetheless physically interchangeable is something Blueair does not state anywhere we could read, and we are not going to guess.
  • THE 2.00 PPB OZONE FIGURE IS ENERGY STAR'S, NOT OURS AND NOT A TEST WE RAN. It is the value recorded in the ENERGY STAR Certified Room Air Cleaners V3.0 dataset for this model number. The 0.00 ppb comparison figures come from the same dataset, for the Honeywell and Medify models we cover. We have not seen either test method.
  • THE THREE CERTIFIERS DESCRIBE THE TECHNOLOGY DIFFERENTLY and we are reporting that rather than resolving it: CARB says Electronic, AHAM records "Fan Filter* with Ion Generator", ENERGY STAR files it as "Fan and Filter".
  • BLUEAIR DOES NOT NAME THE FOUR FILTRATION LAYERS on the product page, so our stage list describes what the page does say rather than enumerating four stages we have not seen documented.
  • ENERGY STAR AND AHAM AGREE EXACTLY ON THIS MODEL but not on its larger sibling: for the 311i+ Max, AHAM records dust 370 and pollen 446 while ENERGY STAR records 364 and 408. That divergence does not affect the figures on this page, which are the 311i Max's.

Our calculation, not the manufacturer’s

What 283 cfm of smoke CADR actually covers

Air changesWhen you want this rateRoom it suits
4.8×/hourWildfire smoke, allergy season, a room you are sensitive in442 ft²
4×/hourThe rate most allergy guidance assumes531 ft²
2×/hourGeneral freshening in a room without a specific problem1061 ft²

Worked from the CDC/NIOSH relation air changes = (CADR × 60) ÷ (area × ceiling height), assuming an 8 ft ceiling. Change the ceiling height and these numbers change. AHAM’s own consumer rule — a smoke CADR of at least two-thirds of the room’s area — puts the ceiling for this unit at about 425 ft², which is the same arithmetic at roughly five air changes an hour.

You can check this at home. In a closed room of the size in the first row, PM2.5 should halve about every nine minutes at top speed once its source stops. A monitor shows whether this unit manages that in your home. How to run the test

Ionizer and ozone

CLASSIFIED ELECTRONIC — AND FOR ONCE THERE IS A MEASURED NUMBER RATHER THAN A REASSURANCE.

CARB's complete list carries "Blueair | Blue Pure 311i Max | 3332111100 | Electronic | 2023-03-09 | G-23-050". Electronic does not mean the machine is an ozone generator; it means California's certifier identified a component capable of producing ozone and therefore TESTED it against the state's emission limit, which it passed. On this machine the component is not a bolt-on ionizer you can switch off — HEPASilent charges particles electrostatically before filtering them mechanically, so the charging stage is how the filtration works.

What is unusual here is that the figure exists. The US ENERGY STAR certified-products list, which records an ozone emission value for every model on it, gives this one 2.00 ppb. For comparison, in that same list the Honeywell and Medify models we cover — both CARB Mechanical — are recorded at 0.00 ppb. So the difference between an electrostatic machine and a purely mechanical one is real, it is measurable, and on this unit it measures two parts per billion.

The three programmes also describe the technology differently, which is worth knowing if you go looking: CARB says Electronic, AHAM's directory records the model type as "Fan Filter* with Ion Generator", and ENERGY STAR files it under "Fan and Filter". Same machine, three taxonomies.

What you actually get

What the linked package includes
Capability What it needs Status
Particle filtration F3MAX cartridge, pre-installed Included
Odour reduction Activated carbon, part of the same cartridge Included
App and Wi-Fi control Blueair app Included
Auto mode with sensor Integrated air sensors, built in Included
Replacement cartridge F3MAX, SKU 110037 — sold separately Sold separately
SmokeBlock or AllergenBlock version Alternative cartridges for the same machine, sold separately Sold separately
Voice assistant control Blueair's page for this model does not describe one Not verified

Package contents vary by variant and seller. Check what is in the box on the Amazon listing before you buy. “Not verified” means the manufacturer does not document it either way — not that it is missing. “Not offered” is the other thing: the manufacturer does document it, and the answer is that this model does not have it.

Replacement filter

Full filter guide

Blueair Blue Pure 311i Max replacement filter

Part F3MAX / SKU 110037 / UPC 689122023298 · "Depending on usage, your filter will last up to 9 months." That is not a calendar figure. Blueair states that its RealTrack algorithm "accurately calculates the remaining filter lifetime based on fan speed, usage time and pollution levels", so the indicator is counting what the machine actually did rather than days elapsed. Nine months is the ceiling, not the schedule: a unit running hard in dirty air will ask sooner.

Which filter fits

How we researched this

Checked against the AHAM Verifide directory, CARB's certified air-cleaner list, the ENERGY STAR certified-products list and the manufacturer's own pages. We did not test this unit. Nothing here is a measurement of ours: every figure is either documented by the manufacturer or published by an independent standards or testing body, and where the two disagree this page says so.

Not verified for this model — 8 notes
  • THE AHAM FIGURES HERE WERE READ IN THE DIRECTORY'S OWN INTERFACE at ahamdir.com on 14 September 2026, not taken from a data dump. AHAM's printed 2023 edition is a snapshot and does not carry every model in the live directory.
  • ⚠️ THE AHAM COLUMN ORDER IS DUST FIRST, THEN TOBACCO SMOKE, THEN POLLEN. The printed directory's own header reads "Dust CADR | Tobacco Smoke CADR | Pollen CADR | Room Size sq FT | Meet Ozone Limits", and the live directory labels the same fields explicitly. Reading the first column as smoke would publish the wrong headline figure and a room size that does not reconcile.
  • ⚠️ THE WRONG COMPATIBILITY LINE WAS VERIFIED IN THE PAGE'S RAW HTML, NOT INFERRED FROM A SUMMARY. Blueair's page for the 311i Max filter mentions "311i Max" 65 times and "311i+" exactly once — and that single occurrence is the compatibility sentence, "This filter is compatible only with the Blue Pure Max 311i+ air purifier". The neighbouring page, for the 311i+ Max filter, carries the identical sentence and mentions "311i+" 60 times. The line appears to have been copied between the two.
  • THE TWO FILTERS ARE DIFFERENT PARTS, WHICH IS HOW WE KNOW THE LINE IS WRONG RATHER THAN THE MACHINES BEING INTERCHANGEABLE. The 311i Max filter carries SKU 110037 and UPC 689122023298; the 311i+ Max filter carries SKU 110038 and UPC 689122023304. Whether the two cartridges are nonetheless physically interchangeable is something Blueair does not state anywhere we could read, and we are not going to guess.
  • THE 2.00 PPB OZONE FIGURE IS ENERGY STAR'S, NOT OURS AND NOT A TEST WE RAN. It is the value recorded in the ENERGY STAR Certified Room Air Cleaners V3.0 dataset for this model number. The 0.00 ppb comparison figures come from the same dataset, for the Honeywell and Medify models we cover. We have not seen either test method.
  • THE THREE CERTIFIERS DESCRIBE THE TECHNOLOGY DIFFERENTLY and we are reporting that rather than resolving it: CARB says Electronic, AHAM records "Fan Filter* with Ion Generator", ENERGY STAR files it as "Fan and Filter".
  • BLUEAIR DOES NOT NAME THE FOUR FILTRATION LAYERS on the product page, so our stage list describes what the page does say rather than enumerating four stages we have not seen documented.
  • ENERGY STAR AND AHAM AGREE EXACTLY ON THIS MODEL but not on its larger sibling: for the 311i+ Max, AHAM records dust 370 and pollen 446 while ENERGY STAR records 364 and 408. That divergence does not affect the figures on this page, which are the 311i Max's.

Sources consulted

Other purifiers we have researched

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