Airmega 400S

I’ve got two cats and a dog, so air purifiers were kind of a must for me. I’ve tried a few, and the one that made the biggest difference was the Coway Airmega 400S. It’s pricey, but it actually cleared that faint pet smell that never goes away no matter how much you clean.

Hey fellow Marylander! I use both a Coway and a Levoit (both linked below) for my home. It’s a bit overkill, but they really helped last year with the fires, given I live about 5 mins from Altadena. For you, I would go with either one of these. I don’t think you will need both. And you can pretty much just leave them on Auto. Set it and forget it [Coway 400](https://a.co/d/0dIKLSPZ) [Levoit 600s](https://a.co/d/002fj62i)

Have you read our [sticky post at the top of the subreddit](https://www.reddit.com/r/AirPurifiers/comments/1jxgjwf/sticky_purifiers_and_dust_reduction/) or the [FAQs wiki page](https://www.reddit.com/r/AirPurifiers/wiki/index/faqs/) entries about dust? Air purifiers aren't good at reducing visible dust as it's large and heavy. I would always avoid Shark. It's a low quality brand and we've had multiple reports of the air quality display not working. Coway purifiers are generally the best quality in the consumer-grade market (although they're more expensive). However, you'd have to buy one with the letter *S* appended to the model name. S-letter models have app connectivity. A great value for money is the Winix C909 sold on Costco.com. It has PlasmaWave, a bipolar ionizer that may be turned on or off. The C909 will be fairly loud on the highest setting called "Turbo" - about 60 dBA according to the Decibel X Android app and it's not very energy efficient at 95W. But purifiers need to be sized by room volume - so please list your room's length x width x height. See **Rule 4**.

No, Dyson is one of the worst! The HP09 has terrible Clean Air Delivery Rates (CADRs). They just know how to market effectively. As **Rule 4** and the AutoModerator comment repeats, it's helpful to know the ceiling height. I'll assume it's 2.4 meters. 60 m^(2) x 2.4 = 144 m^(3). For rooms measured in meters, CADR should be at least 3 times a room's volume (in m^(3)). So the minimum CADR should be 432 m^(3)/h. If you have [allergies, health conditions, high pollution, etc.](https://www.reddit.com/r/AirPurifiers/wiki/index/how_to_choose_an_air_purifier_for_particulates/#wiki_when_higher_than_normal_cadrs_may_be_needed), multiply the room's volume by 4-6. So CADRs of 576 - 864 m^(3)/h. Coway is a high quality brand that's relatively quiet. I don't know exactly where you are, so I don't know what's available to you. But the [Coway Airmega 400](https://www.amazon.co.uk/purifier-restaurant-certified-HyperCaptive-filtration/dp/B099S9Y285) would be a very good fit (Amazon UK website linked). If you can't find that, the Coway Airmega 300 might suffice... although you may want to supplement it with a smaller Coway model like the Coway Airmega Jet.

I wouldn't use ChatGPT or another AI tool to find a purifier. It's frequently wrong about specifications or other details. And I wouldn't recommend Dyson. Their units provide poor particulates cleaning for the money. Per **Rule 4: Information For Air Purifier Requests**, I don't know your country of residence or your budget. I'm guessing you're in Saudi Arabia. The acronym you mentioned is CADR (Clean Air Delivery Rate). As u/timesuck said, purifiers aren't good at reducing visible dust particles as they're large and heavy compared to "invisible" pollutants like PM2.5. Vacuuming and dusting are the better solutions for visible dust capture. I would recommend a bagged vacuum with a HEPA exhaust filter from brands like Miele or Sebo if available. Another important matter is sound output. Infants and young children shouldn't be exposed to overly loud purifiers. According to a *Pediatrics* article, USA hospital nurseries have a recommended sound limit of 50 dBA. Because of this, you'll want to oversize a purifier so you have ample CADR without being too loud. For rooms measured in meters, I would select a high CADR. If PM10 and PM2.5 pollution concentrations are high, I would go with a CADR six times the room's volume in m^(3). Let's assume the nursery has a 2.4 meters high ceiling. Room volume is then 72 m^(3). 72 m^(3) × 6 = 432 m^(3)/h CADR. I would tend to recommend the Coway brand first as they're high quality, energy efficient, and relatively quiet. Something like the **Coway Airmega 400** (top CADR: 677 m^(3)/h) would be great. But it's also expensive. A good choice would be the **Philips Smart Air Purifier PureProtect 4200 Series** (top CADR: 600 m^(3)/h). Keep in mind the CADRs listed for these purifiers apply to the highest airflow speed/setting only. Lower settings have lower CADRs which reduces cleaning effectiveness. Lastly, these two purifiers have little capacity for capturing gases, vapors, odors, or VOCs. This is due to very little activated carbon by weight. Unfortunately you need many pounds of activated carbon or other sorbent media. Heavyweight sorbent media purifiers are very loud and very expensive.

It's difficult to buy just one unit that's great at removing particulates (e.g., pollen, dander, soot, smoke particles, small dust particles, etc.) *and* gases/vapors/odors/VOCs. Most particulates purifiers have very little activated carbon or sorbent media by weight. Oppositely, heavyweight sorbent media purifiers clean the air more slowly than particulates-focused units for several reasons. The thick beds leave less room for mechanical filters (the latter meant for particulates). There's also the need for ["dwell time"/"residence time"](https://www.airscience.com/carbon-filters) for optimized gaseous removal. Unfortunately heavyweight sorbent media purifiers are very loud and very expensive. Infants and young children shouldn't be exposed to overly loud units; a *Pediatrics* [article states the recommended sound limit for US hospital nurseries is 50 dBA](https://doi.org/10.1542/peds.2013-3617). To boot, sometimes you need specially modified sorbents depending on the VOC "species" in your air. Plain/chemically untreated sorbents do not have high removal efficiencies for all gaseous species. **For a list of VOCs and their concentrations, air testing with Gas Chromatography-Mass Spectrometry (GC-MS) analysis is required.** An example of a business performing air testing and analysis is [Fike Analytical Technologies, LLC](https://fikeanalytical.com/). Don't know if they work nationwide. This is why we recommend source control and ventilation strategies first for gases or VOCs. Building-wide solutions could be an Energy Recovery Ventilator (ERV) or a Heat Recovery Ventilator (HRV). # Particulates purifiers I think the concern about Coway's Green HEPA media is overblown, but it's your decision of course. If you change your mind, I might go with the Coway Airmega 400. *Don't* buy the 400 at full price; look for prices of $349 - $450. You may want to consider the [Smart Air Blast Mini MKII](https://www.smarterhepa.com/collections/air-purifiers/products/smart-air-blast-mini) or the [Smart Air Blast MKII](https://www.smarterhepa.com/products/smart-air-blast) instead if you want to avoid antimicrobial coatings. The drawbacks: the Blast Mini and full size Blast are not as energy efficient as the Coway Airmega 400. Both Blast models have an optional activated carbon filter, but the weight of carbon is very low for treating VOCs.

If you need to filter particulates (e.g., smoke particles) *and* smoke gases/vapors/odors/VOCs, you really need two types of air purifier. Most common purifier brands have very little activated carbon or other sorbent media by weight. They are designed to capture particulates quickly. You need many pounds of sorbents for longer-term or high concentrations of gases/vapors/odors/VOCs. Heavyweight sorbent media purifiers are very loud, very expensive, and clean the air more slowly than particulates-focused units. This is due to the need for "dwell time"/"residence time" and the thick media beds. If you're in a country outside of the USA and Canada, you have fewer choices for sorbent media purifiers. Usually the only choice would be the IQAir GC or GCX series units, specifically models using potassium permanganate (KMnO₄) impregnated activated alumina. KMnO₄ improves the removal (via redox reaction) of formaldehyde.\* As for VOC or PM2.5 sensors, most consumer-grade purifiers use very cheap and inaccurate ones. I would invest in a standalone AQI monitor like the [PurpleAir](https://www2.purpleair.com/products/list) (Flex or Zen models) or the [AirGradient ONE](https://www.airgradient.com/indoor/). These are more accurate. Of the brands & models you listed, the Coway Airmega 200M would likely be best. I'm unsure if other Coway models are offered, but I would more strongly recommend the Coway Airmega 240, Coway Airmega 250, or Coway Airmega 400 if they are available to you. \*As an oxidizer, KMnO₄ has the potential to produce problematic byproducts depending on the gases in the air. This is usually an issue with highly complex or unknown air chemistries (fires in the built environment or chemical spills).

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.

Yup, we splurged on a couple coway airmega 400 purifiers when we were living in Seattle and are glad we brought them with us to Minneapolis since we bought an older craftsman home without a duct AC system (which typically allow air filters). This past week would have been really rough for my asthma without air purifiers running!

I just purchased a coway 400 and a levoit Everestair. Have had 2 winix for about two years, Honeywell and germ guardian before that. The coway feels and looks the most premium the coway and levoit both seem nicer upon initial impressions than any of the others but I have only had a few days. One of my winix motor broke about a year and a half in but people generally seem to have good experience with them? The levoit app is really nice and I already had levoit items if you like that sort of option. I bought the levoit for that purpose and the coway because it was on a good sale and recommended by so many. It's kinda loud and annoying pitch to the motor though that's probably going to vary per person

I just see like the newish hap5300 for example and on paper it's very quiet and energy efficient a long time ago had a big unit from them that was Loud so I wonder if people just haven't given the newer ones a chance and they do perform well or if they just don't perform in real life like they do on paper. I'm mostly just curious I suppose. We just yesterday bought an airmega 400 and that is for sure loud but boy does it move the air.

Just wanted to say your comments are so educational! I wish I had found this sub before purchasing my air purifiers but I did end up getting the Coway airmega 400 for my living room, coway 160 for my sons bedroom and have a few Costco winix in the other rooms. The coway sees to pick up much more dust and smells than the Winix. Currently have construction going on in our home and the coway have really picked up so much.