Blueair 311i Max vs Levoit Core 400S: Blueair for Most Rooms

How the Blueair 311i Max and Levoit Core 400S Compare

What They Have in Common

Both are round, mid-size purifiers built for a bedroom, home office or living room, and both stack three layers: a pre-filter, a fine-particle filter and a carbon layer. Each has an air-quality sensor that drives an auto mode, a quiet setting for overnight, and a Wi-Fi app for schedules and remote control. Both are cheap to run around the clock. So the choice comes down to five real differences.

Which One Clears a Room Faster?

On paper, the Blueair is ahead. Blueair rates the 311i Max at 283 cfm for smoke and a 439 sq ft room, against 231 cfm and 358 sq ft for the Core 400S. The outlets that tested both split, though. TechGearLab scored the 311i Max’s air cleaning 9.1 to the Core 400S-P’s 8.5 and names the Blueair its best overall air purifier; Engadget found the Levoit’s overall filtering slightly better and keeps it as its top pick, with the Blueair as an honorable mention.

The real-room tests are closer, and they tip slightly toward the Levoit. Air Purifier First ran both at top speed for an hour: each improved the air in a 320 sq ft room by 96%, and in a 560 sq ft room the Levoit reached 91% to the Blueair’s 89%. HouseFresh’s smoke test showed the same small gap, with the Levoit taking its 728 cubic-foot room to zero PM1 in 24 minutes and the Blueair in 27.

Even: both clean a mid-size room well. The Blueair’s higher rating gives it more margin in a bigger room, and the Levoit was marginally quicker in two independent tests, so decide on smells, noise and upkeep.

Which Handles Cooking and Pet Smells Better?

This is the Levoit’s clearest win. Its carbon stage is pelleted activated carbon, and HouseFresh counts 240 grams in the standard filter, 400 grams in the Pet Allergy and Toxin Absorber versions and 450 grams in the Smoke Remover. HouseFresh also notes that more carbon slows the airflow, so the standard filter remains the better choice when particles are the main concern. Air Purifier First, which compared the pair directly, says the Levoit “uses a significantly better carbon filter”.

The Blueair’s carbon sits in a thin, carbon-treated fabric layer inside the main filter. It copes with light smells from cooking or pets, but testers found it no match for heavy odors or chemical fumes. Reviewed rated its chemical and VOC removal acceptable, at about 70% of the average its lab has measured. Blueair sells a SmokeBlock filter with twice the activated carbon of its original filter.

Pick the Levoit Core 400S if cooking, pet or smoke smells are part of the reason you’re buying a purifier.

Which Is Quieter?

Both are quiet enough to sleep beside on their lowest settings. HouseFresh measured 34.9 dBA for the Blueair and 35.5 dBA for the Levoit from 3 feet. TechGearLab’s decibel meter, 6 feet away, showed 28 for the Blueair and 29 for the Levoit on their lowest settings.

At full power, the tests disagree. HouseFresh measured the Blueair a little lower, at 57.7 dBA to the Levoit’s 60.3, and so did Air Purifier First, at 59.5 dBA to 59.9. TechGearLab’s highest-setting readings show a wider gap, 48 against 54. Engadget’s readings went the other way: it lists a maximum of 69 for the Blueair and 64 for the Levoit.

The side-by-side test still prefers the Levoit’s sound. Air Purifier First heard a buzz from the Blueair at maximum that it found irritating, and calls the Levoit the better optimized of the two for noise. RTINGS, on the other hand, finds the Core 400S noisy at higher fan speeds, with a somewhat higher-pitched tone than other Levoit Core models.

Even: at the speeds most people run overnight, the gap is a decibel or two, and at full power the tests disagree on which is louder. Decide on the other differences, or on how sensitive you are to a motor’s tone at full power.

Which Costs Less to Run and Look After?

The Blueair uses less electricity. HouseFresh measured 29.2 watts at its top speed against 39.64 watts for the Levoit, and by Air Purifier First’s figures a month of round-the-clock running at maximum costs about a fifth less on the Blueair. Either way, electricity is a small part of what you’ll spend.

Filters even things out. The Blueair’s genuine filter is the cheaper of the two, but Blueair rates it for up to 9 months (its filter page also lists 6), and testers put its real life at 6 to 9 months. Levoit’s manual says to replace its filter about every 12 months, while HouseFresh budgets for one every six. That puts their yearly filter costs in much the same range (the table has both stores), and Air Purifier First reckons the Levoit slightly cheaper to maintain over a year.

Day-to-day upkeep favors the Blueair. Its fabric pre-filter sleeve goes in the washing machine, though TechGearLab found it takes some finesse to replace. On the Levoit, the mesh pre-filter is bonded to the main filter: Levoit says to brush or vacuum it every two to four weeks and never wash it, and, as HouseFresh points out, once the carbon is spent the whole filter has to be replaced.

Pick the Blueair 311i Max if you’ll run it all day and want a pre-filter you can simply wash.

Does the Blueair’s Always-On Ionizer Matter?

Blueair’s HEPASilent design puts an electrostatic charge on incoming particles so a thinner filter can catch them while the fan works less hard. It works like an ionizer, and it stays on all the time: there’s no button or app setting to turn it off. Ozone is the usual worry with an ionizer, and Health Canada tells buyers to avoid devices that produce it, steering them to California’s certification list. The Blueair is on that list in the electronic category, where the ozone ceiling is 0.050 parts per million. TechGearLab reports an output of just 2 parts per billion. The Levoit has no ionizer at all.

The sensors differ too. The Levoit’s laser dust sensor feeds a live PM2.5 number on top of the unit, so you can see the air improve without opening an app. The Blueair shows a light that changes color with air quality on the unit and keeps its live readings in the Blueair app, which also lets you set the fan anywhere between its preset speeds.

Pick the Levoit Core 400S if you’d rather have no ionizer at all, or want the air-quality number on the purifier itself.

Consider Instead: Blueair Blue Pure 311i+ Max for a Bigger Room

Both of these are mid-size purifiers. For an open-plan space beyond about 440 sq ft, Blueair’s taller Blue Pure 311i+ Max raises the smoke rating to 339 cfm and the recommended room to 525 sq ft, with the same HEPASilent design, so the ionizer point above still applies.

Which Air Purifier Should You Buy?

For most bedrooms, offices and living rooms, the Blueair 311i Max is the one to buy. It’s rated for the bigger room, draws less power, is lighter (7.8 lb to the Levoit’s 11) and has a pre-filter you can throw in the wash. It’s a close call, though: Air Purifier First’s side-by-side test calls the Levoit the better buy overall after a contest it describes as “extremely tight”, and Engadget keeps the Levoit as its top pick. The Levoit Core 400S is worth choosing when smells are part of the job or you’d rather go without an ionizer: its pelleted carbon, with heavier-carbon filters to swap in, and its live PM2.5 display make it the better fit near a kitchen or a litter box. Either one will keep a mid-size room’s air clean.

Which to buy

1

Best for most rooms

Blueair Blue Pure 311i Max

Buy the Blueair if particles and low running power come first.

4.5/5SCORE

$169.99Deal $255.98

Amazon ReviewsAmazon ReviewsRead our reviewRead our review

2

Best for smells

Levoit Core 400S Smart Air Purifier

Buy the Levoit if odors matter or you want no ionizer.

4.2/5SCORE

Deal $189.97$269.99

Amazon ReviewsAmazon ReviewsRead our reviewRead our review

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How We Compared

We compared the two on what decides a mid-size purifier: how quickly it cleans a room, how it handles smells, noise at the speeds you’ll actually run, running costs and upkeep, and whether it uses an ionizer. The comparison draws on independent lab and editorial tests from Air Purifier First (including its side-by-side test of this pair), HouseFresh, TechGearLab, Engadget and Reviewed, RTINGS’ public verdict, both makers’ specifications, Levoit’s manual, Health Canada’s buying guidance and California’s list of certified air cleaners. The two appear in the order of our review scores.