A pre-filter catches hair and lint, the H13 layer is rated to trap 99.97% of particles at 0.3 microns, like dust, pollen and pet dander, and activated carbon takes on cooking and pet odors.
It Reads the Air and Adjusts Itself
The PM2.5 sensor shows your air quality as a green, orange or red ring. In auto mode the fan speeds up when you cook or vacuum and slows down when the air is clean.
Under 24 dB in Sleep Mode
Sleep mode runs the fan at its lowest speed with the display off, so it can stay on all night in the bedroom.
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Made for bedrooms, nurseries and home offices
Cosari ClearAir 300 Smart Air Purifier
H13 HEPA + carbon · PM2.5 auto mode · Under 24 dB sleep mode
The ClearAir 300 ranked #1 in Report Review's 2026 air purifier comparison for filtration, smart control and value for money.
What you get
In the box
Cosari ClearAir 300 air purifier
3-stage filter (pre-filter, H13 True HEPA, activated carbon), pre-installed in a protective bag
24 V power adapter with US plug
User manual
Technical details
CADR: 177 CFM / 300 m³/h (manufacturer rating)
Room size: up to 1,076 sq ft (one air change per hour)
Filter: pre-filter + H13 True HEPA + activated carbon, about 2,000 h life
Sensor: infrared PM2.5, green / orange / red ring
Modes: auto, sleep, 4 fan speeds, 2/5/8 h timer, child lock
Noise: under 24 dB (sleep) to 55 dB (max)
Power: 3-48 W, 24 V adapter (100-240 V input)
Size: 13.2 x 7.6 x 17.5 in, about 8 lb
Smart: Wi-Fi app (2.4 GHz), Alexa and Google Assistant
Ready in 3 steps
Unbag, Plug In, Switch to Auto
1
Unbag the filter
Lift the front cover and take the protective bag off the filter. Put the cover back on.
2
Plug in and tap power
Connect the adapter at the lower left side and tap the power icon. The ring lights up with your air quality.
3
Choose auto
Tap auto and the fan follows the PM2.5 reading. Pair the app over 2.4 GHz Wi-Fi for schedules and voice.
Our Promise
Buy it, use it at home, and decide.
Return it within 30 days of delivery
Faulty or damaged? We email a prepaid label
Free tracked shipping across the US
Email support from a real person
97% would recommend (demo)
What our customers say
4.7★★★★★Based on 30 demo reviews
Dana R.
10/13/2026
★★★★★
Turns orange the second I start cooking
Put it at the edge of the kitchen. When I fry anything the ring goes orange, the fan kicks up, and a few minutes after I'm done it's green and quiet again. Fun to watch honestly.
Owned 6 weeks · Illinois
Chris P.
10/12/2026
★★★★★
Dog hair finally stays off the pre-filter
Two shedding dogs. I vacuum the pre-filter every couple of weeks and you can see what it pulls out of the air. The living room smells less like dog too.
Owned 2 months · Texas
Megan T.
10/12/2026
★★★★★
Can't hear it at night
Sleep mode turns the display completely off and I genuinely forget it's running. My old one had a blue light I had to tape over.
Owned 5 weeks · Oregon
Jorge L.
10/11/2026
★★★★★
App took two tries
The app only sees 2.4 GHz Wi-Fi, so I had to switch my phone over to pair it. After that schedules and Alexa work fine. Purifier itself is great.
Owned 1 month · Florida
Alison K.
10/11/2026
★★★★★
In the nursery
Bought for the baby's room. Auto mode keeps it low most of the time and the timer is handy for naps. Cover off, bag off the filter, done.
Owned 7 weeks · Ohio
Ben W.
10/10/2026
★★★★★
Studio apartment by a busy street
The reading jumps when I open the window in the morning and it handles it on its own. Small enough to sit next to the bed.
Owned 3 months · New York
Priya S.
10/10/2026
★★★★★
Cat litter smell is way down
Keep it in the hallway near the litter box. The carbon layer makes a real difference. Filter life shows on the display so I know when to order one.
Owned 2 months · Georgia
Tom H.
10/09/2026
★★★★★
Loud on max, quiet on auto
Top speed is noticeable, like a fan. Auto rarely goes there though. Wish it came with a spare filter in the box.
Owned 6 weeks · Colorado
Renee M.
10/09/2026
★★★★★
Fireplace season helper
We light the fireplace a lot and the ring tells us when the room needs it. Ask Google to put it on auto and forget it.
Owned 2 months · Michigan
Kevin D.
10/08/2026
★★★★★
Easy setup
Out of the box in five minutes. Only thing to remember is the plastic bag on the filter, the manual says it in bold.
Owned 3 weeks · Arizona
Lauren B.
10/08/2026
★★★★★
Bedroom stays fresh with two cats
Cats sleep on our bed and the room used to smell like them by morning. With the ClearAir on auto overnight it doesn't anymore. The pre-filter fills with fur, I vacuum it off every other week.
Owned 2 months · Washington
Marcus J.
10/07/2026
★★★★★
Wildfire smoke days
During the smoke advisory the outdoor reading was bad and the ring went red when I opened the door. Closed up, left it on auto and it was green again within the hour in my bedroom.
Owned 2 months · California
Stacy V.
10/07/2026
★★★★★
Wish a spare filter came with it
Works great and quiet. I ordered a spare filter right away because I run it 24/7 and the counter says about 2,000 hours. Would be nice if one was in the box.
Owned 5 weeks · Nevada
Paul G.
10/06/2026
★★★★★
The color ring is the best part
I didn't think I cared about air quality numbers. Now I watch the ring change when I vacuum or burn toast. It's oddly reassuring to see it go back to green.
Owned 1 month · Pennsylvania
Hannah O.
10/06/2026
★★★★★
Quieter than our old tower fan
On sleep it's basically silent and the display goes dark. My husband is a light sleeper and hasn't noticed it once.
Owned 7 weeks · Minnesota
Darnell W.
10/05/2026
★★★★★
Home office upgrade
Sits next to my desk, auto mode most of the day. Room feels less stuffy on long work days and it doesn't get picked up on calls.
Owned 6 weeks · Maryland
Erica N.
10/05/2026
★★★★★
Takes a corner but worth it
It's about 17 inches tall and needs a little room on the front and back for the intakes. Found a spot by the window and it's been great.
Owned 3 weeks · Massachusetts
Victor R.
10/04/2026
★★★★★
Smells from the kitchen gone faster
Fish night used to linger until the next day. Now it's mostly gone by bedtime with the purifier on high for an hour after dinner.
Owned 2 months · Louisiana
Mia T.
10/04/2026
★★★★★
Alexa routine works
I have it in my good night routine: lights off, purifier to sleep mode. Works every time since I set it up.
Owned 1 month · Tennessee
George P.
10/03/2026
★★★★★
App pairing was fiddly
Took me three tries to connect because my router mixes 2.4 and 5 GHz. Once on the 2.4 network it's been solid. The purifier itself I'd give 5.
Owned 3 weeks · Ohio
Kelly S.
10/03/2026
★★★★★
Dog bed corner is fresh now
Put it near the dog beds. The doggy smell in the living room is way down and I see the fur on the pre-filter.
Owned 2 months · Kansas
Nathan L.
10/02/2026
★★★★★
Easy filter swap
Counter hit zero after a few months. Cover off, old filter out, new one in, hold the button five seconds. Two minutes total.
Owned 4 months · Utah
Rachel F.
10/02/2026
★★★★★
Dorm room winner
Small enough for my dorm and quiet enough that my roommate likes it too. The timer is great for falling asleep.
Owned 6 weeks · Indiana
Omar K.
9/28/2026
★★★★★
High is loud, auto is perfect
On 4F you definitely hear it. I almost never use it, auto picks the right speed and stays quiet most of the day.
Owned 5 weeks · Illinois
Tina M.
9/27/2026
★★★★★
Arrived in a week, well packed
Box came in 6 business days with foam all around. Only setup step is taking the plastic off the filter.
Owned 3 weeks · Missouri
Brian C.
9/26/2026
★★★★★
Better than the one I paid more for
I had a bigger-name purifier with no sensor. This one reacts on its own and has the app. Moved the old one to the garage.
Owned 2 months · Colorado
Sophia H.
9/25/2026
★★★★★
Love the child lock
Toddler kept pressing buttons on our old one. Long-press lock and he can't change anything now.
Owned 7 weeks · North Carolina
Dale E.
9/24/2026
★★★★★
Good for a mid-size room
Our open living area is bigger than its rating so it takes longer on high. In the bedroom it's quick. Get the size right for your room.
Owned 1 month · Oklahoma
Ana R.
9/23/2026
★★★★★
Smoke from the neighbors' grill
Summer evenings the ring goes orange when the neighbors grill. It ramps up and settles back on its own.
Owned 2 months · Arizona
Jake M.
9/28/2026
★★★★★
Simple, quiet, does the job
No complicated menus. Power, auto, sleep. Runs all day and I forget it's there.
Owned 6 weeks · Oregon
Cosari ClearAir 300
Half Price, Today Only
Was $299.99, now $149.99. Free tracked US shipping and 30-day returns.
Rooms up to 1,076 sq ft for one full air change per hour (manufacturer rating, CADR 177 CFM / 300 m³/h). In a 300 sq ft bedroom it cycles the air about 3 to 4 times an hour.
02How loud is it?
Under 24 dB in sleep mode with the display off, and up to about 55 dB on the highest fan speed.
03How often do I change the filter?
The filter is rated for about 2,000 hours. The filter-life indicator counts down and flashes when it is time; running day and night, that is roughly every 3 months.
04How long does delivery take?
Most orders arrive in 5-7 business days. Shipping is free and tracked, and you get the tracking link by email.
05What if it is not right for me?
Return it within 30 days of delivery. If it arrives faulty or damaged, we email you a prepaid return label.