The catch
Blueair Blue Pure 311i Max
It isn't suitable if you insist on no ionizer, because HEPASilent leaves its ionization stage active.
Side by side
Blueair 311i Max vs Blueair 211i Max: 211i brings airflow for open rooms, 311i is easier to move around
Quick verdict
For an open living area, go with the 211i Max. The 311i Max is easier to carry from room to room and takes less space in a smaller room.
Before you buy
Why, and what it costs you
Compare room sizes at an equal turnover rate
At five air changes per hour and with an eight-foot ceiling, the figures work out to about 425 square feet for Blueair 311i Max and 653 for Blueair 211i Max.
Where this comes from
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 283 and 435 CFM, along with 8 feet and 5 changes. The CADR used is the smoke figure at maximum speed. Air mixing, furniture, open doors and filter loading all influence real conditions.
The catch
Blueair Blue Pure 211i Max
You can't turn off the HEPASilent ionization stage, which stays active all the time.
Blueair Blue Pure 311i Max
- Why pick it
- Upstairs trips with the purifier are frequent
- Your room measures about 400 square feet or smaller
- The catch
- It isn't suitable if you insist on no ionizer, because HEPASilent leaves its ionization stage active.
Blueair Blue Pure 211i Max
- Why pick it
- More smoke airflow is required
- It stays put in a single large room
- The catch
- You can't turn off the HEPASilent ionization stage, which stays active all the time.
We may earn a commission from qualifying Amazon purchases. How we make money
What this page compares
The 211i Max is the pick for an open living area. In a smaller room, the 311i Max takes up less space and is easier to move between rooms.
The bigger model clears a meaningful room-size threshold
Which one fits
Pick the situations that sound like you
The room is big enough to call for extra airflow
At the same five-change target and eight-foot ceiling, Blueair 311i Max has a calculated limit of 425 square feet and Blueair 211i Max has 653. If you want to run below maximum speed, allow some margin.
- Blueair Blue Pure 311i Max
- Depends
- Blueair Blue Pure 211i Max
- Better fit
The cabinet needs to fit next to furniture
Blueair 311i Max calls for 12.5 inches of width and 12.5 inches of depth, while Blueair 211i Max calls for 14.4 by 14.4. Intake clearance comes on top, so measure the gap in both directions.
- Blueair Blue Pure 311i Max
- Depends
- Blueair Blue Pure 211i Max
- Depends
I want to run it from another room
App control is supported on both Blueair 311i Max and Blueair 211i Max, so it doesn't tell them apart. Move on to the room and placement checks.
- Blueair Blue Pure 311i Max
- Better fit
- Blueair Blue Pure 211i Max
- Better fit
Ceiling height is ten feet
Take the ceiling up to ten feet with five air changes and the modeled room areas fall to 340 square feet for Blueair 311i Max and 522 for Blueair 211i Max. That is 20% less floor area than the eight-foot example, as the purifier has more air to move.
- Blueair Blue Pure 311i Max
- Depends
- Blueair Blue Pure 211i Max
- Depends
In practice
Differences you will notice
Compare room sizes at an equal turnover rate
At five air changes per hour and with an eight-foot ceiling, the figures work out to about 425 square feet for Blueair 311i Max and 653 for Blueair 211i Max.
How we worked this out
Area = CADR × 60 / (ceiling feet × air changes per hour). Inputs are 283 and 435 CFM, along with 8 feet and 5 changes. The CADR used is the smoke figure at maximum speed. Air mixing, furniture, open doors and filter loading all influence real conditions.
Measure the cabinet first, then buy
Blueair 311i Max has a 156.3-square-inch cabinet envelope, versus 207.4 for Blueair 211i Max. A shallower shape can still need more wall width.
How we worked this out
Width × depth: 12.5 × 12.5 = 156.3 in² and 14.4 × 14.4 = 207.4 in². These are the cabinet bounding rectangles, without the required air clearance.
The larger size gives more airflow for each rated watt
Compared with the 311i Max, the 211i Max lists about 54% more smoke CADR in exchange for about 44% more rated input.
How we worked this out
(435 / 283 - 1) × 100 = 53.7% and (46 / 32 - 1) × 100 = 43.8%. Actual electricity use depends on fan settings and sensor activity.
Plug in your numbers
Can either purifier keep up with your room?
This checks hard limits only. Personal preferences are left out of the math.
Blueair Blue Pure 311i Max
Works with your numbers283 CFM of verified clean-air delivery works out to about 7.1 air changes per hour in this room. Hitting the 5 ACH target takes 200 CFM.
Blueair Blue Pure 211i Max
Works with your numbers435 CFM of verified clean-air delivery works out to about 10.9 air changes per hour in this room. Hitting the 5 ACH target takes 200 CFM.
This uses each model’s pollutant-specific CADR at top speed and a target of five air changes per hour. Quieter settings clean less air. Raw airflow and one-change coverage claims are never swapped in.
Option A
Blueair, 311i Max
Blue Pure 311i Max
Quiet and smart, this cylinder falls between Blueair's compact 511i and larger 211i and delivers serious smoke airflow given its 12.5-inch base.
- Best for
- Medium rooms that call for strong airflow, a washable fabric prefilter and quiet smart operation
Facts we checked
- Certified CADR is 283 CFM for smoke, 314 for dust and 365 for pollen.
- At 4.8 air changes per hour, Blueair lists 439 square feet.
- The cabinet is 12.5 inches wide, with app and automatic modes, and is rated from 23 to 50 dB.
Option B
Blueair, 211i Max
Blue Pure 211i Max
This large-room cylinder runs quietly and efficiently, with a high CADR, a washable fabric prefilter and handy app automation.
- Best for
- Open living areas, pets and smoke, when quiet high airflow outranks deep gas filtration
Facts we checked
- Blueair lists a room size of 674 square feet at 4.8 air changes per hour.
- Published CADR is 435 CFM for smoke, 452 for dust and 450 for pollen.
- The purifier weighs 16.2 pounds, has app, auto and night modes, and is rated at 23 to 53 dB.
Spec by spec
Where they really differ
| Spec | Blueair Blue Pure 311i Max | Blueair Blue Pure 211i Max | In practice |
|---|---|---|---|
| Smoke CADR | 283 CFM | 435 CFM | Better to rely on a smoke-specific rate than on a one-air-change marketing room size. |
| Pollen CADR | 365 CFM | 450 CFM | The model that leads on smoke does not necessarily lead on pollen as well. |
| Cabinet width and depth | 12.5 × 12.5 in | 14.4 × 14.4 in | Check both dimensions against the real gap, and keep the clearance the manual calls for around the intakes. |
| Remote app control | Included | Included | Remote schedules matter if the purifier sits far from where you spend your day. |
| Automatic sensor response | Included | Included | Apps and pollution sensors do separate jobs, and a schedule tells you nothing about air quality. |
| Ionizer or electrostatic stage | always-on | always-on | If a purely mechanical filter path is what you want, treat this preference as a firm requirement. |
| Published weight | 7.8 lb | 16.2 lb | A heavy cabinet bothers you less if it stays put than if it must go upstairs every day. |
| Rated power | 32 W | 46 W | Rated input is a comparison of upper limits. Actual consumption shifts with Auto mode and lower fan settings. |
Trade-offs
What each pick costs you
With Blueair Blue Pure 311i Max
- The carbon layer targets lighter household smells and is not meant for lingering solvent or renovation fumes.
With Blueair Blue Pure 211i Max
- To keep airflow up, the fabric prefilter has to be vacuumed or washed from time to time.
Decision guide
How to decide
Pick the 211i Max for an open living area. Moving between rooms is easier with the 311i Max, which also uses up less space in a smaller room.
The bigger model clears a meaningful room-size threshold
The 211i Max reaches about 653 square feet at our five-change target with eight-foot ceilings, against about 425 for the 311i Max. That is enough to change the answer in many living rooms.
If you move it often, the 311i wins
At 16.2 pounds against 7.8, the 211i Max is the heavier unit. A permanent downstairs spot suits that weight better than a daily carry from bedroom to home office.
Output rises by more than the power draw does
Smoke CADR climbs from 283 to 435 CFM while rated input goes from 32 to 46 watts. Treat these as nameplate comparisons and not as measured running costs in Auto mode.
What this page can’t tell you
- CADR is based on the maximum rated fan speed, and minimum noise and maximum airflow occur at different operating points.
- What these calculations compare is particle-cleaning capacity. Nothing in them promises health outcomes or the removal of a specific gas.
By the numbers
What the data shows
What we found across the air purifiers we compare, plus the checked facts behind each finding.
How many fit
Only 14 of the 70 models checked meet every need here: “Wildfire smoke makes its way inside”, “Floor space is very tight for me”, and “I want it to respond automatically”.
14 models fit, out of 70 checkedThe gap in numbers
Blueair Blue Pure 211i Max lists 435 CFM for listed smoke CADR, 54% more than the 283 CFM on Blueair Blue Pure 311i Max.
- Blueair Blue Pure 311i Max
- 283 CFM
- Blueair Blue Pure 211i Max
- 435 CFM
- Models with this figure
- 20 of 70
Show the facts and the math
How we countedThe count uses each product's current fit ratings for “Wildfire smoke makes its way inside”, “Floor space is very tight for me”, and “I want it to respond automatically”. A need with no documented match is not counted.
How we calculatedOnly figures stated as smoke CADR go into this median. General maximum-airflow numbers are left out. For context, 20 of 70 models publish comparable figures.
| Product | Needs it meets | Facts we checked | Sources |
|---|---|---|---|
| Blueair Blue Pure 311i Max |
|
| |
| Blueair Blue Pure 211i Max |
|
|
Ready to buy
See today’s price and what owners say
Open either model on Amazon for the current price, customer reviews and delivery options.
Blueair Blue Pure 311i Max
Upstairs trips with the purifier are frequent
See price & reviews on AmazonBlueair Blue Pure 211i Max
More smoke airflow is required
See price & reviews on AmazonEach link opens in a new tab.
We may earn a commission from qualifying Amazon purchases. How we make money