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Blueair 511i Max vs 311i Max: Which Fits Your Room and Filter Plan?

For a smaller room and tighter placement, the 511i Max has the smaller published footprint and a 237-sq-ft recommendation at 4.8 ACH. The 311i Max is a larger-body option with a 439-sq-ft recommendation at the same stated air-change rate. These are Blueair's published room-fit figures, not a head-to-head cleaning result; one separate Blueair specs table gives a conflicting 194-sq-ft figure for the 511i Max. Filter matching is model-specific: F5MAX for 511i Max, F3MAX for 311i Max.

Published by Pickoryx · Published 2026-10-03

Source checked 2026-10-03 21:15 UTC

Products compared

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The buying question

Does the smaller 511i Max fit the room and placement, or does the 311i Max's larger stated 4.8-ACH room recommendation fit better—and which replacement filter family belongs to each?

Blueair's product pages recommend the 511i Max for 237 sq ft and the larger 311i Max for 439 sq ft at 4.8 air changes per hour; the 311i Max also has a taller, wider footprint. Their replacement filters use different families: F5MAX for the 511i Max and F3MAX for the 311i Max.

Quick verdict

Choose Blueair Blue Pure 511i Max Air Purifier if

  • The measured room and placement fit the 511i Max's 237-sq-ft 4.8-ACH recommendation and 14.5 x 9.3 x 9.3 in footprint; verify with Blueair if your room is close to the conflicting 194-237-sq-ft boundary.
  • You want the smaller listed enclosure and can identify the correct F5MAX replacement family when it is time to change the filter.
View Blueair Blue Pure 511i Max Air Purifier on AmazonPaid link

Choose Blueair Blue Pure 311i Max Air Purifier if

  • The 311i Max's 439-sq-ft 4.8-ACH recommendation better matches the room you are planning for and its 19 x 12.5 x 12.5 in footprint fits the location.
  • You can keep the exact model name handy and order the F3MAX filter family rather than a filter for another Blue Pure Max model.
View Blueair Blue Pure 311i Max Air Purifier on AmazonPaid link
When the recommendation changes
  • For a room near the 511i Max's 194-237 sq-ft band, check with Blueair: its detailed product page states 237 sq ft at 4.8 ACH, while a separate support specs table lists 194 sq ft without naming an ACH basis.
  • Measure the intended location before choosing; the 311i Max has a larger base and is taller, while no same-condition cleaning test is provided here.

The differences that matter

Room Sizing And Placement

Blueair Blue Pure 511i Max Air Purifier

Blueair recommends 237 sq ft at 4.8 ACH for the 511i Max; dimensions 14.5 H x 9.3 W x 9.3 D in.[1]

Blueair Blue Pure 311i Max Air Purifier

Blueair recommends 439 sq ft at 4.8 ACH for the 311i Max; dimensions 19 H x 12.5 W x 12.5 D in.[2]

What this changes: The same stated 4.8-ACH basis makes these room-fit values comparable as manufacturer recommendations, while the two bodies differ in footprint and height. A separate official specs table conflicts with the 511i Max page on room area, so a buyer near that boundary should confirm the recommendation.[1, 2, 3]

The better fit depends on your priorities

Replacement Filter Family And Specialty Options

Blueair Blue Pure 511i Max Air Purifier

The 511i Max uses the F5MAX family; Blueair's page limits the standard F5MAX filter to that purifier. SmokeBlock and AllergenBlock choices are also listed for this model.[4, 5]

Blueair Blue Pure 311i Max Air Purifier

The 311i Max uses the F3MAX family; Blueair's page limits the standard F3MAX filter to that purifier. SmokeBlock and AllergenBlock choices are also listed for this model.[4, 6]

What this changes: Keep the exact purifier model name when ordering. The standard families differ, while both models list the same named specialty-filter categories; no filter cost or service-life comparison is made.[4, 5, 6]

The better fit depends on your priorities

Best for your routine

A room whose placement favors the smaller listed body and whose size fits Blueair's 511i Max recommendation

Best fit: Blueair Blue Pure 511i Max Air Purifier

Based on listed features, not comparative testing.

The manufacturer lists the 511i Max at 237 sq ft at 4.8 ACH and gives a smaller 14.5 x 9.3 x 9.3 in footprint. The separate 194-sq-ft support-table value means buyers near that room boundary should verify with Blueair.

View Blueair Blue Pure 511i Max Air Purifier on AmazonPaid link

A room planned around Blueair's 311i Max 4.8-ACH recommendation, with floor space for its larger body

Best fit: Blueair Blue Pure 311i Max Air Purifier

Based on listed features, not comparative testing.

Blueair lists a 439-sq-ft recommendation at 4.8 ACH and dimensions of 19 x 12.5 x 12.5 in; confirm the footprint at the intended location.

View Blueair Blue Pure 311i Max Air Purifier on AmazonPaid link

Value and trade-offs

One or both observed offers have eligibility conditions, so no unrestricted price difference is shown.

Compare current checkout offers only after confirming room fit and the exact replacement-filter family you would need. No filter or long-term ownership-cost comparison is included.

No usable price-history window is included here, so there is not enough history to say whether to buy now or wait.

Limitations

  • Blueair's detailed product pages state 237 sq ft at 4.8 ACH for the 511i Max and 439 sq ft at 4.8 ACH for the 311i Max. Their larger 30-minute/one-hour cleaning-area figures are a different presentation and are not substituted for the shared 4.8-ACH basis.
  • Blueair's separate Product Specs table lists the 511i Max as up to 194 sq ft, while its detailed U.S. product page recommends 237 sq ft at 4.8 ACH. The page title also carries a 465-sq-ft label. The comparison uses only the detailed 4.8-ACH recommendation and flags the conflict for buyers near that room-size boundary.
  • Room layout, ceilings, openings, pollutant load and desired air-change rate affect placement. No same-condition cleaning, health-outcome, noise or air-quality winner is claimed.
  • Blueair's lookup lists SmokeBlock and AllergenBlock options for both exact models; the standard replacement families are model-specific. Filter prices, replacement intervals and total ownership costs are not compared.
  • Pickoryx did not hands-on test either purifier. Price history is unavailable, so this comparison does not recommend when to buy.

Questions shoppers ask

Which model fits the larger room at the same stated air-change rate?

Blueair recommends the 511i Max for 237 sq ft and the 311i Max for 439 sq ft, both at 4.8 ACH on their detailed product pages. Blueair's separate specs table lists 194 sq ft for the 511i Max without stating an ACH basis, so confirm directly with Blueair if your room is near that boundary. These ratings are not a same-condition cleaning test.

Can I use the same replacement filter for both?

No. Blueair maps the 511i Max to F5MAX and the 311i Max to F3MAX, and the corresponding standard-filter pages each limit compatibility to the named purifier. Both lookup entries also list SmokeBlock and AllergenBlock options, but those options still belong to their model's filter family.

Methodology and sources

Compared the same stated 4.8-ACH manufacturer room recommendations, published dimensions, the conflicting support-table entry, and the official exact-model replacement-filter mappings. No paired air-cleaning test or ownership-cost comparison was performed.

Automated tools helped locate and organize the cited manufacturer pages. Recommendations are limited to published room-fit specifications and exact model-specific filter compatibility.

View 6 sources
  1. 1.Blue Pure 511i MaxBlueair · Official specifications · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Product title/model, FAQ 'What room size is best' and Technical Specifications: The U.S. page identifies Blue Pure 511i Max. It recommends 237 sq ft at the AHAM recommendation of four air changes every 12.5 minutes and lists 4.8 ACH; dimensions are 14.5 x 9.3 x 9.3 in (H x W x D). It also gives separate larger 30-minute and one-hour room figures, which are not treated as the 4.8-ACH recommendation.
  2. 2.Blue Pure 311i MaxBlueair · Official specifications · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Product title/model, FAQ 'What room size is best' and Technical Specifications: The U.S. page identifies Blue Pure 311i Max. It recommends 439 sq ft at the AHAM recommendation of four air changes every 12.5 minutes and lists 4.8 ACH; dimensions are 19 x 12.5 x 12.5 in (H x W x D). Its separate 30-minute and one-hour area statements are not treated as the 4.8-ACH recommendation.
  3. 3.Product SpecsBlueair Support · Official support · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Blue Pure 311i Max and Blue Pure 511i Max rows, published May 19, 2026: The support table lists dimensions of 19 x 12.5 x 12.5 in and up to 439 sq ft for 311i Max, matching its detailed product page; it lists up to 194 sq ft for 511i Max, differing from the detailed product page's 237 sq ft at 4.8 ACH. The table does not state an ACH basis for these room-size entries, so the 194 value is disclosed as a conflict rather than used as an equivalent rating.
  4. 4.Filter Lookup TableBlueair Support · Official support · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Blue Pure 311i Max row 1110033 and Blue Pure 511i Max row 1111178: The 311i Max row maps to F3MAX and lists F3MAX SmokeBlock and AllergenBlock filters. The 511i Max row maps to F5MAX and lists F5MAX SmokeBlock and AllergenBlock filters. These rows are model-specific; both purifier models have named specialty-filter options.
  5. 5.F5MAX Replacement PAC filter for 511i MaxBlueair · Official specifications · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Product heading and compatibility statement for Blue Pure 511i Max F5MAX replacement filter: Blueair identifies this as the Blue Pure 511i Max F5MAX Particle + Carbon filter and states it is only compatible with the Blue Pure 511i Max. The page also displays the AllergenBlock and SmokeBlock categories for this purifier; no prices, subscriptions or filter-life claims are used.
  6. 6.Blue Pure 311i Max FilterBlueair · Official specifications · Source checked 2026-10-03 21:15 UTC
    Evidence used on this page
    • Product heading and compatibility statement for Blue Pure 311i Max F3MAX replacement filter: Blueair identifies this as the Blue Pure 311i Max F3MAX Particle + Carbon filter and states it is only compatible with the Blue Pure 311i Max. The page also displays the AllergenBlock and SmokeBlock categories for this purifier; no prices, subscriptions or filter-life claims are used.

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