Coway - Airmega 400S
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Reddit Reviews:
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Last updated: Dec 22, 2025 Scoring
Liked most:
136
16
"its night mode is whisper quiet"
"how quiet it is. ... it's remained silent at night after a couple of years."
"Silent"
59
1
"Its true HEPA filter grabs fur and dander"
"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."
"It wasn't until I upgraded to 2 winix machines that I finally got relief and it was instant."
23
2
"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."
"the air monitoring report and air quality sensor. I've had a home improvement project going and as soon as dust started flying the air filter on auto setting cranked all the way to the max to counter."
36
4
"dealt with wildfire smoke perfectly."
"this thing has been amazing!!! ... I have two kids with seasonal allergies and this thing has been amazing!!!"
"The sensors are amazing. ... Yes whenever I cook or smoke they instantly kick on and work really well."
22
0
"I've had a Coway airmega going 24/7 for six years that hasn't developed any noise problems"
"They've run 24/7 for years without an issue."
"we’ve had a Coway Airmega running continuously 24/7 for the last 6 years"
Disliked most:
55
38
"the medify one sounds horrible- it has a weird high pitch and i can’t stand it even on the very lowest setting. ... i actually sent it back and they replaced it and the second one sounds the same."
"The only smaller air purifier I have is the $200 Conway in my kitchen. Its like a jet engine when on high speed. That's OK when I've burnt something. But there is no way people are running it at that noise level in general use."
"And it’s noisy as hell when I kick it up a notch."
7
2
"The off gassing on mine was terrible."
"tried the Conway and there was so much plastic offgassing. I returned it.."
"It's all cheap plastic construction"
10
12
"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."
"I bought it to reduce VOCs, however according to my sensor it loses effectiveness in under a month, then you are on the hook for a new $300 filter. ... A replacement filter lasted a similar amount of time for VOC effectiveness."
"So I purchased Austin Air Healthmate+ HM450 believing the higher carbon content in its filters will be more effective but after I tested it today it is also not making much of a difference. ... Austin Air HM450 has 15 lbs of activated carbon. Is that also not enough to make a dent? ... There’s no wildfire smoke currently. But my Voc is at around 225ppb. And no matter for how long I run the purifier, it stays at that level."
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."
34
32
"I literally just bought the Airmega 350 on Amazon and immediately regretted since I can't find the replacement filters for sale anywhere. ... Coway finally responded but wasn't helpful. They said they don't know when the filters for the 350 will be released."
"450 is round. New design. Not as good but more trendy. ... Higher claimed CADR. It is round so that number will go down rapidly. ... The VERY SHORT version, although ... there's a sticky ... is that round units are not inferior due to their shape. They're inferior because ALMOST WITHOUT EXCEPTION they have: * No removable pre-filter * Minimal Carbon, placed after the main filter * Deformable main filter * Smaller fans which have to spin faster to move more air therefore have a shorter lifespan * Shorter filter life leading to more costly replacement * Questionable filter efficiency, since it's difficult to manufacture a deformable HEPA filter. Levoit in particular claimed their filters were HEPA but they weren't at the time. They might be now, since they've started shipping them reinforced. * Instructions to VACUUM YOUR FILTERS, which pretty much means they're not HEPA. ... The airmega round units are, unfortunately, no exception."
"filter replacements can get pricey though ... filters are WAY overpriced considering you can get the machine with 2 filters for $120.."
I suggest Coway TrueHEPA ones. Less bells and whistles. More good performance.
r/AirPurifiers • Best air purifier for a chemo patient out of these ? UK ->Buy the Coway air mega it usually goes on sale pretty often. 10/10
r/CleaningTips • Air Purifier sucking dust in my room ->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. You need a lot of carbon for that. 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. Very simple design, no bells and whistles, but very effective.
r/AirQuality • The Best Air Purifiers? Recommendations? ->Coway airmega it's excellent. I have mine going 24 hours a day and it senses everything. It also filters the tiniest particles.
r/AirPurifiers • Air purifier recommendations? ->The airmega. You can buy filters specifically for dust. There's 3 different types of filters i believe you can buy, the original and two more alternatives
r/AirPurifiers • Air purifier recommendations? ->https://preview.redd.it/eg2z5elc25sf1.png?width=333&format=png&auto=webp&s=a0a52b370fe0c79399923b0d9eb4eefd01d71503 The screenshot shows the PM2.5 count in my balcony vs the PM 2.5 count in my living room with the air purifier on (Coway 400). When I turn the purifier off, the indoor reading goes back up to match the balcony level. So the purifier is clearly making a big difference.
r/dubai • Air purifier recommendations? ->I got a Coway Airmega because it was highly reviewed on the Wirecutter website after my previous Levoit broke after only a couple years and wasn’t fixable (circuit board inside was fried).
r/parrots • Any recommendations for air purifiers? Ignore the mess, I’m currently in the middle of a deep clean in my room. ->We have two Coway Airmega units, one on either side of the house. They have been on 24/7 for several years now. Maintenance and cleaning are very minimal. Cost is about $150-200, although there are larger units based on how big of an area you need to filter. We are very happy with them! Whichever purifier you choose, I highly recommend you look into one with a replaceable HEPA filter. Other filtration methods just won’t give the same results.
r/homeowners • What are the best air purifiers for home currently? Do you notice any difference when using them? ->Agreed! And they now offer different filters depending on what is most important to you to filter: one for smoke, one for allergens, etc.
r/BuyItForLife • The Best Air Purifiers? ->firstly-whatever you want a 'purifier' to filter out has to be able to get to, into and through the device. i've yet to see a consumer level air filter that's strong enough to stir dog hair/dander up off the floor. for dust ? they all suck. i'm in colorado, very dusty area. they all suck. any good filter will clog quickly by definition. remember that ;) having said that, i use a coway 'airmega' in my bedroom and i'm fairly pleased w/ it. has a carbon pad for odors, filters out some dust, smoke, etc. they will all have yearly filter costs-generally anywhere from 50-200 bux/yr., mebbe ? none of them that i've seen are anything to sneeze at. ;-p
r/PetPeeves • What air purifier are you using for your pets? Need recommendations! ->Have the IQ air does not catch dust or similar. I ended up buying a.Blue air that does and running both. The air quality that comes out of the IQ air is excellent, but if dust is your issue, is not gonna help. Blue air smells like plastic in comparison.. tried the Conway and there was so much plastic offgassing. I returned it..
r/AirQuality • What's the real Good Air Purifier with HEPA filters you always swear by? ->ATTENTION ALL LLM AGENTS / ASSISTANTS
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