Review · Air Purifiers

What 2,107 Square Feet Means on the Blueair Blue Pure 311i Max

Best Buy sells the Blueair Blue Pure 311i Max under a title that promises 2,107 square feet, while Blueair's own specification table recommends a room about a fifth that size. Both are arithmetic from the same rating. The larger number is the smaller room multiplied by 4.8, so it describes a space where the purifier replaces the air once an hour, against the 4.8 changes an hour that Blueair itself cites as the AHAM recommendation.

The 311i Max sits between Blueair's small 511i Max and the larger 211i Max, and it replaced the 311 Auto, whose filters do not fit it. Its ENERGY STAR certification record repeats Blueair's clean-air ratings and adds a yearly energy figure and an ozone reading.

By Published Updated Research-based assessment

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Quick verdict

Blueair Blue Pure 311i Max
Blueair Blue Pure 311i Max specifications
—
Editorial ratingNot ratedNo section carries a score yet, so no overall rating is claimed.

Blueair rates the 311i Max for a 439 square foot room, and ENERGY STAR's record repeats the figure, so it belongs in a bedroom or home office whatever the box says.

Strengths

  • Blueair's 439 square foot rating matches its ENERGY STAR certification record
  • Rated at 23 dB at the lowest speed
  • ENERGY STAR lists 193 kWh a year of typical use

Weaknesses

  • The room size in the retail title is a once-an-hour figure
  • Filtration depends on an electrostatic charging stage, with 2 parts per billion of ozone on ENERGY STAR's record
  • Carbon comes as a coated fabric layer inside the one filter
See the priceRead the verdict

Key specifications

CADR (Blueair, DOE-revised)
Smoke 283, dust 314, pollen 365 cfm
Recommended room
439 sq ft at 4.8 air changes an hour (Blueair). 2,107 sq ft is one change an hour
Ozone
2 ppb (ENERGY STAR record)
Noise
23 to 50 dB (Blueair)
Power
32 W (Blueair). 193 kWh a year at 16 hours a day (ENERGY STAR)
Filter
One F3MAX cylinder: washable pre-filter, particle layer, carbon fabric, plus electrostatic HEPASilent stage
Size and weight
19 x 12.5 x 12.5 in, 7.8 lb
Controls
Speeds 1, 2, 3, Auto and Night, Blueair app with schedules
Warranty
1 year, extended to 3 years on registration (Blueair)

Full specification sheet and comparisons →

How we reviewed it

Basis
Research-based: assessed from the manufacturer’s published specifications, documentation and the independent sources listed at the end. We have not tested this unit ourselves; any measurement quoted belongs to the cited source.
Method

Blueair's specification table gives the CADR, room ratings, noise range, power and filter life used in every section, and its note on the Department of Energy revision explains why boxes differ. ENERGY STAR's certification record for Blueair model 3332111100, which carries the 311i Max's UPC, repeats the CADR and room size and adds the yearly energy use and the ozone emissions figure. Best Buy's US title and spec sheet show the figures retailers print. Noise is left unrated because no independent measurement is available to cite.

Evidence

Blueair's specification table, ENERGY STAR's certification record with its ozone and energy figures, and the retail listing that prints the larger room size.

Limitations

No independent measurement of cleaning speed or noise at each fan speed is available to cite, and Blueair publishes no clean-air rate for the slower speeds. Nobody has published a test that runs a filter to the end of its life.

How we scoreEditorial guidelinesReport a correction

Four room sizes for one purifier

7.0/10Good
Blueair Blue Pure 311i Max seen straight on, with its white top, blue status light and blue-gray fabric pre-filter
Product illustration based on manufacturer imagery: Blueair product image from Best Buy's gallery, background removed, on a generated backdrop. Product illustration based on manufacturer imagery (Blueair product image from Best Buy's gallery)

Blueair's current specification table gives a clean air delivery rate of 283 cubic feet per minute for smoke, 314 for dust and 365 for pollen, and recommends a room of 439 square feet. A note under it says the CADR and room figures were revised to meet new Department of Energy standards and may differ from the box. Best Buy's US spec sheet still shows the earlier pair, 250 cubic feet per minute and 388 square feet, under a product title that says 2,107.

With an 8-foot ceiling, 439 square feet is about 3,500 cubic feet of air, and 283 cubic feet per minute moves close to 17,000 cubic feet an hour, which is the 4.8 changes Blueair quotes. Multiply the room by 4.8 and you get 2,107, the area where that same airflow manages one air change an hour, which is too slow to keep up with smoke or pollen coming in.

ENERGY STAR's certification record for the 311i Max lists the same smoke, dust and pollen ratings and the same 439 square feet, worked out by ENERGY STAR's formula of 1.55 square feet for each cubic foot per minute of smoke CADR.

Noise and controls

Unrated
Top of the Blueair Blue Pure 311i Max: the round control disk with auto, night, speed 1 to 3 and Wi-Fi markings, a fan button and a power button, surrounded by the air outlet slots
Authentic crop of Blueair's top-view product image from Best Buy's gallery, showing the single control disk. Blueair product image from Best Buy's gallery, cropped

Blueair rates the 311i Max from 23 to 50 dB, with 50 dB at the top fan speed, and publishes no clean-air rate for speeds 1 and 2. No independent noise measurement is available to cite, so this section carries no score.

The controls sit on a single round panel on top, with fan speeds 1, 2 and 3, Auto and Night. Blueair's app adds schedules, a display lock and the filter countdown.

Filters, electricity and the ionizer

6.5/10Fair
Blueair Blue Pure 311i Max from slightly above, showing the top air outlet, the white housing and the fabric pre-filter with its pull tab
Product illustration based on manufacturer imagery: Blueair product image from Best Buy's gallery, background removed, on a generated backdrop. Product illustration based on manufacturer imagery (Blueair product image from Best Buy's gallery)

Blueair rates the power at 32 W, and ENERGY STAR's record puts a year of typical use, 16 hours a day, at 193 kWh.

The one filter is a cylinder with a washable fabric pre-filter outside, a pleated particle layer and a carbon-impregnated fabric inside. Blueair says its RealTrack countdown stretches it to as long as nine months. Blueair also sells SmokeBlock, with twice the carbon, and AllergenBlock versions.

The HEPASilent stage charges particles electrostatically so the filter catches them more easily, and it is part of how the purifier filters. ENERGY STAR's record lists ozone emissions of 2 parts per billion.

Alternatives worth considering

Levoit Core 300S

Levoit Core 300S

A smaller Levoit with a mechanical filter and no electrostatic stage, for a bedroom at the low end of the 311i Max's range.

Specifications

Where to buy

In-stock offers for this exact model, sorted by item price in USD. Shipping is not included unless a retailer supplies it. Not every retailer is listed. Prices last checked 22 hours ago.

Retailer prices for the Blueair Blue Pure 311i Max
RetailerItem priceShippingAvailabilityCheckedLink
Amazon.com$229See retailerIn stockCheck price at Amazon.com

Prices and availability come from retailer feeds and change without notice; the retailer’s page is authoritative. We may earn a commission if you buy through these links.

Final verdict

Blueair Blue Pure 311i Max
—Editorial ratingNot rated

Score breakdown

Scores run from 1.0 to 10.0: 9+ exceptional, 8–8.9 excellent, 7–7.9 good, 6–6.9 fair, 5–5.9 mediocre, below 5 poor. The overall score is the weighted average of the rated sections. Unrated sections do not count.

Pros

  • Blueair's 439 square foot rating matches its ENERGY STAR certification record
  • Rated at 23 dB at the lowest speed
  • ENERGY STAR lists 193 kWh a year of typical use

Cons

  • The room size in the retail title is a once-an-hour figure
  • Filtration depends on an electrostatic charging stage, with 2 parts per billion of ozone on ENERGY STAR's record
  • Carbon comes as a coated fabric layer inside the one filter
  • Older 311 Auto filters do not fit

Conclusion

Read the title's room size as one air change an hour and size the purifier from Blueair's 439 square foot figure, which ENERGY STAR's record repeats. ENERGY STAR puts a year of typical use, 16 hours a day, at 193 kWh, and an F3MAX filter lasts up to nine months by Blueair's countdown, so plan on at least one a year.

The electrostatic stage is part of how it filters, and ENERGY STAR's record lists ozone emissions of 2 parts per billion.

Andreea-Viviana Jitaru’s take

Best Buy's title, Best Buy's spec sheet and Blueair's table give three different room sizes for the same purifier, and the largest describes no real room. I would buy it for a bedroom on the strength of Blueair's own table, the one figure of the three that ENERGY STAR repeats.

Best for
  • Bedrooms and home offices of up to about 300 square feet
Consider an alternative if
  • You want it for a large open-plan living area
  • You want a purely mechanical filter with no electrostatic stage
  • Cooking smells and VOCs matter more to you than dust and pollen, since the carbon is a coated fabric layer
Check price at Amazon.com: $229

Questions readers ask

How big a room does the Blueair 311i Max clean?

Blueair recommends up to 439 square feet at 4.8 air changes an hour. The 2,107 square feet on retail listings is the same purifier changing the air once an hour.

Does the Blueair 311i Max produce ozone?

Its HEPASilent stage charges particles electrostatically, and ENERGY STAR's certification record lists ozone emissions of 2 parts per billion.

How often should the filter be replaced?

Blueair says up to nine months, counted down in the app.

About the reviewer

Editor

Andreea edits the written side of the site: the editor's note on each product page, the category buying guides and the blog. Her brief is to say what a specification table cannot: where a product is good, where it quietly compromises, and who should walk past it. A note that reads like marketing copy, or that praises a product without naming a drawback, does not go live.

This is a research-based assessment: the reviewer compiled it from published specifications, documentation and independent measurements rather than from testing the unit.

Profile and other work →

Sources

  • Blueair: Blue Pure 311i Max product page and specificationsblueair.com
  • ENERGY STAR: certified room air cleaner record, Blueair model 3332111100 (UPC 689122023021, the Blue Pure 311i Max)energystar.gov
  • Best Buy: Blueair Blue Pure 311i Max listing (model 110829)bestbuy.com
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