Blueair Blue Pure 311i Max Review
The mid-size machine with the best coverage-per-watt figure in its class, read against both registers. We do not test units; this is the certified record.
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The efficiency pick at mid size: 283 certified smoke CADR across 439 certified square feet on 29.6 watts, which is $35 a year at 8.4 CFM per watt. Its pollen figure is the best in the category relative to its size. The asterisks: 2 ppb measured ozone, an ion classification the registers dispute, and nothing published about noise or filter cost.
The disclosure that shapes everything below: we have not tested this unit. We own no air purifiers and run no laboratory. What follows is what two certification registers publish about this model, plus the arithmetic we can do on it — our method, including where it runs out.
The certified record
| Specification | Figure | Source |
|---|---|---|
| Smoke CADR | 283 CFM | AHAM VERIFIDE |
| Dust CADR | 314 CFM | AHAM VERIFIDE |
| Pollen CADR | 365 CFM | AHAM VERIFIDE |
| PM2.5 CADR | 298 CFM | AHAM VERIFIDE |
| Certified room size | 439 sq ft | AHAM, at 4.8 ACH |
| Two-thirds-rule room | 424 sq ft | Our arithmetic on the CADR |
| Annual energy use | 193 kWh | AHAM |
| Electricity per year | $35 | Our arithmetic at a named rate |
| Power draw | 29.6 W | AHAM |
| Air per watt | 8.4 CFM/W | AHAM |
| Measured ozone | 2 ppb | ENERGY STAR |
| Technology (AHAM) | Fan Filter with Ion Generator | AHAM VERIFIDE |
| Technology (ENERGY STAR) | Fan and Filter | ENERGY STAR |
| Filter classification | HEPA-Type | ENERGY STAR |
| Noise | Not published in our sources | — |
| Filter interval and price | Not published in our sources | — |
Electricity costs on this page use 18.34¢ per kWh, the U.S. average residential price for June 2026 from the U.S. Energy Information Administration, Electric Power Monthly, Table 5.3. Your rate is on your bill and is probably not this one; multiply the kWh figure by your own rate and you have your number.
The number that makes it interesting
8.4 CFM per watt is the second-best efficiency figure on this site, behind only its larger sibling and the Airmega ProX. In practice that means 439 certified square feet for $35 a year — less than half what the LEVOIT Core 600S costs to run for 38% more coverage.
Over a machine’s life that gap is the strongest argument for it. Over three years the 311i Max asks for about $106 in electricity against about $213 for the Core 600S — though neither figure includes filters, because Blueair publishes nothing to compute them with.
The pollen number, and who should care
Every machine posts a higher pollen CADR than smoke CADR, because pollen is the largest of the three test particles. This one posts 365 against 283 — 29% higher, the widest gap in our data. Its larger sibling manages 3%.
If seasonal allergy is the reason you are buying and the room is inside its coverage, this machine punches above where the headline number places it. Ranking a pollen problem on the smoke column misranks machines, which is why the pollen roundup ranks on the pollen column instead.
The asterisk, in detail
AHAM classifies this model “Fan Filter with Ion Generator”. ENERGY STAR records the same model number as “Fan and Filter” and publishes a measured ozone emission of 2 ppb. Both cannot be a complete description of one machine, and we are not in a position to adjudicate between two certification bodies.
Two parts per billion is small — the program limit is 50, and several machines we cover measure higher. It is also not the 0.00 ppb the Honeywells, the LEVOIT Core range and the certified Coways return, and Blueair does not document a way to switch the stage off. EPA advises avoiding portable cleaners that intentionally produce ozone, because ozone is a lung irritant — how we weigh that against a good efficiency figure.
What Blueair does not publish
Two gaps, both of which competitors fill. No noise figure we could source, which matters for a machine likely to sit in a room people use all evening — LEVOIT publishes a dB range for every Core unit. And no filter interval or replacement price, so half the running cost is unquotable.
The Amazon listing also advertises 2,107 square feet against 439 certified. That is the same machine measured at one air change an hour instead of 4.8 — how coverage claims are manufactured from CADR.
Who should buy it
Buy it for a room up to about 424 square feet where running cost is the deciding factor, pollen is a seasonal problem, and nobody in the household has asthma or a respiratory condition.
Buy something else if a measured zero on ozone matters — the Honeywell HPA6000 and the Medify MA-40 both return one at similar size — or if the room is larger than about 424 square feet, where the 211i Max is the correct size rather than the bigger one.
What the register cannot tell you
Three things a buyer should weigh that no certification covers. There is no published dB figure for this machine, so the quiet-enough-for-a-bedroom question cannot be answered from data — and on a machine this efficient, the temptation is to run it higher than you otherwise would.
The filter is a single cylindrical cartridge rather than a stack, which is simple to change and gives you no choice of composition: there is no carbon-heavy option to specify if odor turns out to be your real problem. And because Blueair publishes no replacement interval, the honest budgeting advice is to watch the machine rather than the calendar — rising noise at the same setting is the usual sign a cartridge is loading up.
Quick picks
The 311i Max against the two machines a buyer at this size should weigh it against.
| # | Product | Best for | Certified CADR | Price |
|---|---|---|---|---|
| 1 |  The unit reviewed Blueair Blue Pure 311i Max 283 certified CFM across 439 sq ft on 29.6 watts, pollen CADR 365. | Mid-size rooms on a small electricity bill | 283CFM smoke AHAM VERIFIDE | |
| 2 |  If the ozone figure decides it Honeywell HPA6000 257 certified CFM, 0.00 ppb measured, recorded HEPA not HEPA-Type. | Large living rooms, true HEPA | 257CFM smoke AHAM VERIFIDE | |
| 3 |  If the room is bigger Blueair Blue Pure 211i Max 435 certified CFM across 674 sq ft at 9.0 CFM per watt. | Open-plan spaces above 500 sq ft | 435CFM smoke AHAM VERIFIDE |
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The alternatives worth weighing
Honeywell HPA6000
Honeywell · model HPA6000B
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More certified air movement than the HPA4300 for four more watts, and the same zero on ozone. The sensible step up if your room is nearer 400 square feet.
257 smoke / 262 dust / 285 pollen CFM · 259 PM2.5
- Certified room size
- 398 sq ft
- Energy / year
- 207 kWh
- Electricity / year
- $38
- Air per watt
- 7.3 CFM/W
- Power draw
- 34.9 W
- Noise
- Not published
- Measured ozone
- 0 ppb
- Filter class
- HEPA
- AHAM rule, 380 sq ft
- Clears it (254 needed)
257 certified smoke CADR across 398 certified square feet with 0.00 ppb measured, no ion stage, and a filter the register records HEPA rather than HEPA-Type — at $38 a year.
The honest con: 7.3 CFM per watt is behind the Blueair, it covers less room, and Honeywell publishes no noise figure or filter cost either.
Blueair Blue Pure 211i Max
Blueair · model 3613111100 (Blue Pure 211i Max)
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The most air per watt of anything here and by some distance the largest certified coverage — 674 square feet. It does carry an ion generator, which is the reason it is not our asthma pick.
435 smoke / 453 dust / 450 pollen CFM · 444 PM2.5
- Certified room size
- 674 sq ft
- Energy / year
- 256 kWh
- Electricity / year
- $47
- Air per watt
- 9 CFM/W
- Power draw
- 44 W
- Noise
- Not published
- Measured ozone
- 2 ppb
- Filter class
- HEPA-Type
- AHAM rule, 600 sq ft
- Clears it (400 needed)
Ion generator — fitted
The two registers disagree: AHAM classifies this model 'Fan Filter with Ion Generator' while ENERGY STAR records it as 'Fan and Filter'. ENERGY STAR's measured ozone figure is 2 ppb. We report both rather than picking the flattering one.
The same design one size up: 435 certified smoke CADR across 674 certified square feet at 9.0 CFM per watt, the best efficiency figure on this site. The two compared, with the crossover computed.
The honest con: identical ion-stage dispute and 2 ppb measurement, so it answers the size question and not the ozone one, and it costs $47 a year against $35.
Common questions
Is the Blueair 311i Max worth it?
What size room is the 311i Max good for?
Does the Blueair 311i Max produce ozone?
Is the 311i Max good for pollen?
Sources
- AHAM VERIFIDE directory of certified room air cleaners
- ENERGY STAR certified room air cleaners database
- EPA — Guide to Air Cleaners in the Home
Figures were read on the dates shown against each source. If one has changed, or if we have got something wrong, tell us and we will correct the page.
Read next
- Room sizeBlueair 211i Max vs 311i MaxIdentical on ozone, ion status and filter class. Separated only by 283 CFM against 435 — and the crossover lands at 439 sq ft.
- AllergiesThe Best Air Purifiers for PollenRanked on the certified pollen CADR rather than the smoke figure, which moves several machines up the table.
- CADR & costThe Best Air Purifiers Under $300Under $300 buys genuine large-room coverage. Ranked on certified CADR, running cost and measured ozone — not on sticker price alone.