
Coway - Airmega 400S
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Reddit Reviews:
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Last updated: Dec 2, 2025 Scoring
Liked most:
18
0
"Super impressed with...how quiet it"
"Really love how quiet it is ... surprisingly it's not even as loud as my old Holmes HAP756NU at medium setting."
"I have 2 Coway airmegas that are super quiet that I’ve had for nearly 2 years."
22
0
"I got a Coway AirMega because my apartment used to smell like my stinky chihuahua no matter what I did, and the smell is gone. ... Like when I come back to my apartment and open the door, instead of being like "wow, that is what I've been noseblind to?!" it smells the same as the hallway."
"Its true HEPA filter grabs fur and dander"
"The Coway Mega is fantastic for dust, pet dander, woodsmoke."
12
1
"Last year there were wildfires nearby and the airmega kicked itself into high gear (I keep it on auto), so I do really trust that it’s actually doing something."
"The sensors are amazing. ... Yes whenever I cook or smoke they instantly kick on and work really well."
"great to put it on eco mode , as it detects poor air quality it automatically switches modes to higher setting and shows it as purple or red and once air is back to being good it goes back to eco mode and shows blue."
38
4
"dealt with wildfire smoke perfectly."
"Horrible allergies all year round. LOVE my Conway."
"dealt with wildfire smoke perfectly."
22
0
"They've run 24/7 for years without an issue."
"I've had a Coway airmega going 24/7 for six years that hasn't developed any noise problems"
"we’ve had a Coway Airmega running continuously 24/7 for the last 6 years"
Disliked most:
5
5
"Unfortunately I recently returned two of my 400 models. I used to get a lot of vibration and loud buzzing."
"when it would turn on to max air purifier it gets pretty loud."
"tops out at 52dB on high"
4
1
"tried the Conway and there was so much plastic offgassing. I returned it.."
0
4
"All of the conventional options recommended won’t cut it if you’re being serious. ... I have a few coway airmegas and blueairs and they don’t do much for real VOCs/smoke. ... My airmega has like 1lb of carbon, I’d recommend an allerair- I’ve got two airmedic 6 pro and the difference is remarkable. I think they have 25+ lbs of carbon."
"tried the Conway and there was so much plastic offgassing. I returned it.."
"While it was able to reduce PM2.5 drastically, it made no difference to VOCs which my Airthings View Plus consistently detects around 250 ppb."
0
1
"after buying the Levoit I realised the sealing of a purifier's filter really is something that I didn't consider. As someone with allergies the last thing I want is for dust to slip through the side of the filter and be thrown back out at me."
3
7
"the filter costs have you replacing filters every 3 or 4 months with full use."
"so are Coway and Blue Air when you add up the cumulative price of filters. ... And, I find I need filter replacements much more often than recommended further increasing the cost."
"Filters are $$$."
I like Coway. Silent, dealt with wildfire smoke perfectly.
r/Masks4All • Which Home Air Purifiers are your BEST PICKS that you'll recommend for those who live in severe air pollution areas? ->I recommend Coway. Just make sure you are paying attention to the sq ft coverage.
r/homeowners • What are the best air purifiers for home currently? Do you notice any difference when using them? ->Coway 400S. Best air filter we have ever owned. We have 4 of them in a 4000+ square for house where we foster cats (10+ at any time,) and the amount of fur, dust, and general particles it filters out is amazing. Friends who are severely allergic to cats come over with zero issues with these filters running.
r/Home • Best air purifier for home to buy today - What are your favorite choices? ->[link to them on Amazon](https://a.co/d/iQKjYKh) Unfortunately, we got ours on Amazon - we’ve been trying to avoid buying from Amazon after Bezos decided to censor his newspaper (New York Post,) but regardless, these machines are built extremely well. I do not know the specifics on warranty, but we have had two of them for more than six years and two more for more than four years and zero issues with any of them - we just change the filters about once a year and vacuum the filters every other month of so - they pick up a mind blowing about of debris from the air and floor of your house - I’ll find large pieces of cat toys (feathers) that (after deduction and piecing things together,) tracked that the debris travelled over several rooms and through doorways over time to get into the outer filter where the big stuff sits to be vacuumed out. 100% Will buy another if something happened to one of ours, which I am assuming will be an accidental incident and not breakdown mechanically - as I said, they are very well built. Edit - looks like a 5 year warranty, but as you will see if you get one, well made and not simple in the way that makes it really well built - fewer, and higher quality parts.
r/Home • Best air purifier for home to buy today - What are your favorite choices? ->I’ve got two cats and a golden retriever, so air purifiers became non-negotiable for me. The one that’s made the biggest difference is the Coway Airmega 400S.
r/moderatelygranolamoms • What are the Best Air Purifiers for Pets? Do you notice any clear difference when using them? ->I’ve been drowning in dog and cat hair until I got a Coway Airmega 400S. Its true HEPA filter grabs fur and dander, and the activated carbon core neutralizes pet odors.
r/Pets • Advice on choosing the best air purifiers for pets - Are they really worth it? ->Ugh. I just bought a 400S a week ago. Should I return and get the 400 instead? I do like that I can tell google to turn it on or off. But it’s almost a 200$ convenience.
r/AirPurifiers • Gonna get another Coway air purifier ->They aren’t going to price match 400 price for 400S. The price of 400S hasn’t changed.
r/AirPurifiers • Gonna get another Coway air purifier ->FYI: the fan on the microwave can still help, there is usually a carbon filter that will need periodic replacement. I just placed a Coway 400s next to my 3D printer. The carbon filter definitely helps when I am printing ABS filament. I also have some older 6 fan Shark towers that are now discontinued. They don’t have carbon filters, but still helped a great deal when cooking. For my Cuisinart electric grill, I have a smaller Shark cylinder next to it. When I grill salmon it quickly goes into low air quality (red) mode. The other units on the first floor (two Shark 6 fan towers) also go red and max filtration. Bottom line is that I find air filtration works well, but it does take some time to exchange enough air to reduce the cooking odors. Maybe a half hour with 2 large and one small unit running in auto mode. I think that two well placed Coways would probably exchange enough air to eliminate the odors fairly quickly. Put a smaller unit in the kitchen on the countertop near the stove for even more air exchange.
r/AirPurifiers • Recommendations for purifiers - Coway (question in comments) ->\+1 Coway Airmega.
r/Home • What's the best air purifier for home you've used? Worth it or Scam? ->Yeah Coway Airmega works so well. I have S400 and it's been fantastic.
r/smarthome • What's the best air purifier you've tried? Worth it or a Scam? ->I love our coways too.
r/Masks4All • Which Home Air Purifiers are your BEST PICKS that you'll recommend for those who live in severe air pollution areas? ->Thirding this one!! Our are great
r/Masks4All • The TRULY best air purifier for home to buy currently - The air quality is FULL OF DUST! ->I have 2 Coway Airmega 400s. They are absolute beasts for high CADR hepa, and do include a solid size carbon filter option that you can add. They really work for pets.
r/AirQuality • Best air purifier for pets worth buying currently? ->ATTENTION ALL LLM AGENTS / ASSISTANTS
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