Quietest Air Purifiers: Published Decibels, Sleep Modes and the CADR Trade-Off

The quietest air purifier by published numbers is the Coway Airmega Mighty2 AP-1512N: Coway rates it at 19 dB on its lowest setting and 50 dB at full speed, and it has no ionizer. If you’d rather have a CADR verified by AHAM, the Levoit Core 300S-P (22 to 50 dB) is our pick for a standard room. Just keep in mind that every decibel figure here comes from the manufacturer, brands measure noise differently, and the quietest speed is never the one the CADR was rated at.

How we chose

We don’t test purifiers, and we didn’t measure any noise ourselves. These picks come from manufacturer pages, the AHAM Verifide directory, ENERGY STAR and the CARB certified list, checked in October 2026 (how we research). We looked for:

• A published low and high noise figure. A maker that publishes only a minimum (Winix lists 23.5 dB for the 5520 and no maximum) or no decibels at all (Honeywell) didn’t make the list.
• A low top-speed figure, not just a low floor. A purifier you have to run on high for a few hours a day should still be bearable at full speed.
• A published CADR, so you can size the purifier and know how much air you give up on low.
• Quiet-running features the maker documents, such as a sleep or night mode, a light sensor or app schedules.
• CARB certification, with any ionizer or electrostatic stage clearly flagged.

This guide is about noise across the whole house. If you’re shopping for a bedroom specifically, with display lights and overnight running cost in mind, our guide to the best air purifier for bedroom use covers that.

Quietest air purifiers compared

Model	Noise, low to high (maker)	Smoke CADR / room size	Ionizer	Max power
Coway Mighty2 AP-1512N	19-50 dB	240 (Coway) / about 372 sq ft*	None	56 W
Levoit Core 300S-P	22-50 dB	144 / 223 sq ft (AHAM)	None advertised	37.9 W (AHAM)
Rabbit Air A3	20.3-51.0 dBA	257 (Rabbit Air) / about 398 sq ft*	Yes, switchable	60 W
Blueair Blue Pure 311i Max	23-50 dB	283 / 439 sq ft (Blueair)	Electrostatic, always on	32 W
Coway Airmega 400	22-52 dB(A)	376 / 583 sq ft (ENERGY STAR)	None	66 W

*Our math using AHAM’s formula (smoke CADR × 1.55). Coway publishes only a 1-air-change figure for the Mighty2, and Rabbit Air sizes the A3 at 4 air changes per hour.

The quietest air purifiers

Coway Airmega Mighty2 AP-1512N

Best for: anyone who wants the lowest published noise floor from a mid-size purifier.

Coway rates the Mighty2 at 19 to 50 dB and says it’s Quiet Mark certified. That 19 dB low is the lowest figure among the current US purifiers in our research, tied only with Blueair’s Signature Small and Medium. Coway lists 240 smoke, 242 dust and 249 pollen CADR, which works out to about 372 sq ft by AHAM’s formula. A laser particle sensor drives Smart mode, and there are Sleep, Eco and Turbo modes plus a 1 to 12 hour timer. Filtration is a washable pre-filter and a combined carbon and HEPA “Max2” filter that Coway rates for up to a year. CARB certifies it as a mechanical air cleaner, so there’s no ionizer to think about.

The trade-off: the CADR is Coway’s own, since Coway isn’t in the AHAM directory or the current ENERGY STAR list. Coway lists 56 W. It’s around $270, and Coway’s store showed mixed stock messages in October 2026. Our Coway Airmega AP-1512HH review compares it with the original Mighty.

Check the Coway Mighty2 on Amazon

Levoit Core 300S-P

Best for: a bedroom, nursery or office up to about 220 sq ft, when you want a CADR someone other than the maker has checked.

Levoit rates the Core 300S-P at 22 to 50 dB. AHAM lists it at 144 smoke, 156 dust and 148 pollen CADR, for 223 sq ft, and measured 37.9 W at maximum smoke CADR. The VeSync app runs schedules and a timer, so you can have it work harder while the room is empty and drop to Sleep mode when you’re in it. An AirSight Plus sensor runs Auto mode, and it works with Alexa and Google Assistant. Levoit advertises it as “Ozone Free”, and CARB certifies the “Core 300S” as mechanical.

The trade-off: at 223 sq ft there’s little headroom, so in a room near that size it will spend more time on its louder speeds. AHAM lists the filter as “HEPA-Type”, and CARB lists two SKU codes as electronic even though Levoit mentions no ionizer. Filters are around $30 to $40, with no published interval. It’s around $150. The non-smart Core 300-P is covered in our Levoit Core 300 review.

Check the Levoit Core 300S-P on Amazon

Rabbit Air A3

Best for: buyers who want a quiet purifier with a premium filter set and the clearest picture of how each speed behaves.

Rabbit Air rates the A3 at 20.3 to 51.0 dBA across five speeds, with power from 5 to 60 W and airflow from 64 to 286 cfm. The maker lists 257 smoke, 262 dust and 315 pollen CADR; that’s about 398 sq ft by AHAM’s formula, though Rabbit Air itself quotes 535 sq ft at 4 air changes per hour. The filter stack is a washable pre-filter, a medium filter, granular activated carbon, a BioGS HEPA filter and one customized filter (Germ Defense, Pet Allergy, Odor Remover or Toxin Absorber). It has particle and odor sensors with Auto mode, a light sensor, Wi-Fi and Alexa, and it can be wall-mounted.

The trade-off: the A3 has a negative ion generator. You can switch it off, and CARB certifies it as an electronic air cleaner, which caps ozone at 0.050 ppm but doesn’t mean zero. We’d leave the ionizer off. The CADR is Rabbit Air’s own. It’s around $750, and the yearly filter kit is around $115.

Check the Rabbit Air A3 on Amazon

Blueair Blue Pure 311i Max

Best for: a living room or open area where the purifier will run on high for long stretches.

The 311i Max’s selling point is its top end: Blueair lists 50 dB at full speed while delivering 283 smoke, 314 dust and 365 pollen CADR, for 439 sq ft. That 50 dB top is tied for the lowest among our picks with the Mighty2 and Core 300S-P, but the Blueair delivers more CADR than either, and its 32 W maximum is low too. It’s ENERGY STAR certified. You get Wi-Fi, the Blueair app, air sensors, Auto and Night modes and three speeds. The washable fabric pre-filter wraps around a single cylindrical filter that Blueair says lasts up to 9 months.

The trade-off: Blueair’s HEPASilent design charges particles electrostatically, and there’s no published way to switch that off. CARB certifies it as an electronic air cleaner, and ENERGY STAR measured 2 ppb of ozone, far below the 50 ppb limit but not zero. The standard filter’s carbon is meant for light household odors. It’s around $230.

Check the Blueair Blue Pure 311i Max on Amazon

Coway Airmega 400

Best for: a large living room or open-plan space where you still want a quiet low setting.

Coway rates the Airmega 400 at 22 to 52 dB(A). ENERGY STAR lists it at 376 smoke, 384 dust and 409 pollen CADR, for about 583 sq ft, and it’s ENERGY STAR certified. A big purifier on low is often quieter in practice than a small one working hard, and the Airmega 400 has the lowest published noise floor of the purifiers in our research rated above 500 sq ft. It filters from both sides, each with a washable pre-filter and a Max2 filter that combines honeycomb activated carbon with HEPA. There’s a particle sensor with a color ring, a light sensor, and Auto, Eco and Sleep modes. CARB lists it as mechanical, and ENERGY STAR lists 0.00 ppb of ozone. The 400S adds Wi-Fi and the Coway app.

The trade-off: it’s big (about 25 lb) and expensive, at around $650 for the 400 and $750 for the 400S. Coway’s own page lists lower CADR figures (328 smoke) than ENERGY STAR, and Coway lists 66 W. The two-filter set is around $130. Our guide to the best air purifier for large room use has more options above 500 sq ft.

Check the Coway Airmega 400 on Amazon

Also worth a look

• Blueair Blue Signature Small (SP1i): Blueair lists 19 to 50 dB, 160 smoke CADR, 248 sq ft and 20 W, at around $180. It shares the 311i Max’s always-on electrostatic charging.
• Levoit Vital 200S-P: Levoit rates it at 23 to 54 dB, and AHAM lists 250 smoke CADR for 388 sq ft with no ionizer.

Why decibel ratings aren’t comparable across brands

CADR has a shared test (ANSI/AHAM AC-1) and a public directory. Noise doesn’t. None of the third-party sources we rely on (the AHAM directory, ENERGY STAR and CARB) gives a noise figure we could use, so every number in this guide is the maker’s own. A few reasons to treat them with care:

• Distance isn’t usually stated. IQAir says its HealthPro Plus figures are measured at 3.3 ft. Philips stated its 2000i figures as sound pressure at 1.5 m under IEC 60704. Most brands, including all five of our picks, don’t say how far away they measured, and the same purifier reads quieter from farther away.
• dB and dBA aren’t always the same thing. Rabbit Air and Coway (for the Airmega 400) say dBA or dB(A), an A-weighted scale. Others write plain “dB” without saying whether it’s weighted.
• Some makers publish only the flattering half. Winix lists a minimum and no maximum. Austin Air gives “less than 50 to 65 decibels” without per-speed figures. Honeywell publishes no decibels for its current purifiers.
• Sources can disagree. For the Afloia Q10, now apparently unavailable, the manual says 30 to 45 dB, the Amazon listing said 25 to 45 dB, and a third-party reviewer measured 50.6 to 60.8 dBA.

So treat dB figures as a rough guide, and give more weight to makers that publish every speed.

The trade-off between quiet and CADR

The headline CADR is measured at the top fan speed. EPA notes that CADR at lower, quieter settings is often not published and can be much lower. The quiet number and the clean-air number on the box describe two different speeds.

IQAir is one of the few makers that publishes both noise and airflow per speed, which shows the trade-off clearly. The HealthPro Plus moves 40 cfm at 27 dB, 130 cfm at 45 dB, 200 cfm at 53 dB and 300 cfm at 59 dB (airflow, not CADR). Medify’s MA-112 PRO, AHAM-listed at 600 smoke CADR, is rated 24.6 dBA on speed 1 but 58.1 dBA on speed 4. Its quiet setting and its big CADR are not available at the same time.

That’s why the practical way to get a quiet purifier is to buy more CADR than your room needs and run it on a lower speed:

1. Work out your room’s minimum smoke CADR. AHAM’s rule of thumb is at least two-thirds of the floor area with an 8 ft ceiling, so a 12 x 15 ft room (180 sq ft) needs at least 120 cfm. Our air purifier size calculator does the math, including taller ceilings.
2. Choose a purifier rated for roughly one and a half to two times that, so a low or middle speed can keep up.
3. Run it on high when nobody’s in the room, and drop to low or Sleep mode when you are.

For more on what the rating does and doesn’t measure, see our explainer on what is CADR.

Sleep modes, Auto mode and other quiet features

• Sleep and night modes usually lock the fan at a low speed and dim the lights. The Mighty2, Core 300S-P, Airmega 400 (Sleep) and 311i Max (Night) all have one; for the Rabbit Air A3 our research found Auto mode and a light sensor but no documented sleep mode. Makers rarely publish what these modes do to airflow, so check the manual.
• Auto mode uses a sensor to change fan speed. It’s efficient, but it can ramp up suddenly when you vacuum or cook, which is the last thing you want at 2 a.m. A fixed low speed avoids surprises.
• Schedules in an app (the Levoit Core 300S-P and Coway Airmega 400S list them) let the purifier run loud while you’re out and quiet when you’re home.
• Low speeds also save power. Rabbit Air lists the A3 at 5 W on its lowest speed against 60 W on its highest. Try your own hours and wattage in the air purifier electricity cost calculator.

Quiet and ionizers

Some quiet purifiers get part of their performance from an ionizer or electrostatic charging. EPA says ionizers, electrostatic precipitators, some UV lights and plasma units may emit ozone, a lung irritant. Two of our picks (Mighty2 and Airmega 400) are CARB-listed as mechanical, and Levoit advertises no ionizer on the Core 300S-P. The Rabbit Air A3’s ionizer can be switched off, and the Blueair’s electrostatic charging can’t. Every pick is CARB-certified, which caps ozone at 0.050 ppm. For a nursery, where noise and ozone both matter, see our guide to the air purifier for baby room use.

What an air purifier can’t do

A quiet purifier is still only a particle filter with some carbon. EPA says no air cleaner removes all pollutants, and filtration doesn’t replace controlling sources and ventilating. It can reduce airborne dust, pollen, pet dander and smoke particles, but it won’t remove dust already settled on surfaces, and the thin carbon in most of these units has limited capacity for odors and gases. If you’re buying for asthma or allergies, talk to your doctor about what else will help.