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Waking up unrefreshed is usually blamed on sleep. Often it is the air in the room you slept in.
The three below differ by $90, by a factor of three in power draw, and by roughly 200 square feet of coverage. Start with the room, not the brand.
| Blueair 311i Max | Blueair 511i Max | Levoit Vital 200S-P | |
|---|---|---|---|
| CADR, pollen | 365 cfm | 174 cfm | 250 cfm |
| Rated room, 4.8 ACH | 439 ft² | 237 ft² | 388 ft² |
| Noise | 23–50 dB | 19–48 dB | 23–54 dB |
| Power draw | 32 W | 17 W | 50 W |
| List price | $229.99 | $139.99 | $189.99 |
| Weak point | Ionizer cannot be switched off | One bedroom only, despite the listing | 50 W, and loudest at full speed |
All three discount through the year and rarely together — start with the current price.
CADR365 pollen · 314 dust · 283 smoke cfmRoom439 ft² at 4.8 ACHNoise23–50 dB · QuietMarkPower32 WList$229.99
Most people are buying one machine, and it ends up in the room where they spend the evening. 439 ft² covers that room in most homes, which is why this is the default rather than the cheapest.
It gets there without the noise penalty you would expect. HEPASilent charges the particles before the filter catches them, so the fan can turn slowly, and 23 dB at the low setting earned QuietMark certification.
Thirty-two watts is modest for that much airflow. Filters run $44.99 and last up to nine months.
The drawback: the electrostatic stage cannot be turned off. It produces only trace ozone, within safety limits, but several competitors put a switch on it and Blueair does not. If someone in the house has asthma, that missing switch is the reason to look at something purely mechanical.
Check today's price on AmazonBlueair Blue Pure 311i Max →
Read the full Blue Pure 311i Max review
CADR174 pollen · 159 dust · 153 smoke cfmRoom237 ft² at 4.8 ACHNoise19–48 dB · QuietMarkPower17 WList$139.99
This is $90 less than the pick above and runs on half the electricity. For a single bedroom, nothing here beats it on cost.
Nineteen decibels is the lowest floor in the group, eleven below a quiet bedroom's own background. At 4.2 pounds you can move it to whichever room needs it.
It is also the only unit here that is CARB Zero Ozone certified, below 5 parts per billion, despite using the same electrostatic method as its larger sibling.
The drawback: the product listing advertises 1,138 ft², a figure that assumes one air change an hour. Blueair's real recommendation is 237 ft². Buy it for a living room on the strength of the larger number and it will not keep up.
Check today's price on AmazonBlueair Blue Pure 511i Max →
Read the full Blue Pure 511i Max review
CADR250 cfmRoom388 ft² at 4.8 ACHNoise23–54 dBPower50 WPre-filterWashableList$189.99
Both Blueairs are built around particles and treat odor as an afterthought. This one is the opposite: Levoit sells pet, toxin-absorbing and smoke versions of the filter at $59.99 to $64.99.
The pre-filter is washable, which the Blueairs do not offer. With a shedding animal in the house that is the difference between rinsing a mesh and buying a filter.
Coverage lands between the two above at 388 ft², and sleep mode drops the fan and switches the display off.
The drawback: 50 watts is three times the 511i Max and the highest here, and full speed has been measured around 57 dBA, loud enough to interrupt a conversation. The three-layer filter is also one piece — when the carbon gives out at about six months, a serviceable HEPA layer goes in the bin with it.
Check today's price on AmazonLevoit Vital 200S-P →
Read the full Levoit Vital 200S-P review
Measure the room and match it to the rated area at 4.8 air changes per hour, not the larger figure on the box. What Size Air Purifier Do You Need? Size It by CADR, Not the Box sets out the arithmetic.
Undersizing is the most common mistake here, and it is invisible — the machine runs, it just never catches up.
Two small ones, usually, if the rooms are separate. Air does not travel between closed rooms, so a purifier only cleans the room it is standing in.
Less than most people expect. At 17 to 50 watts you are looking at roughly 150 to 440 kWh a year — what it costs to run an air purifier 24/7 puts real rates against those figures.
As an Amazon Associate I earn from qualifying purchases. This post contains affiliate links. We were not given these products and were not paid to write about them.
