CowayAirmega 400S(G) App-Enabled Smart Technology Compatible with Amazon Alexa True HEPA Air Purifier, Covers 1,560 sq. ft, Graphite

This unit seems very accurate. Every time my wife cooks, it kicks into high speed from the smoke. I'm not joking, it actually does. Even if it's just a strong smell from the cooking, it goes into high speed. I even heard it kick in one time after I sneezed. I've already cleaned the outer filter 3 times since purchasing it (about a month now), so it's collecting. And we no longer see the dust floating around when the sunlight shines through the windows in the morning. It's made a big difference.On the cons side, I see no reason for this thing to make a sound when it changes mode. When I configured the auto mode change at night and in the morning, it make a bing-bing sound 3 times in a row about 10 seconds between. It's in our living room, so no big deal, but if you plan to sleep nearby, it would be annoying.Another con, the app is not that great. I had to disable it sending alerts, because the only alert it sends is that your air quality is extremely bad. And it did it so often that I finally disabled it. But then when I opened the app, and viewed the air quality readings, it was never in the extremely bad range, or only hit it once or twice, much less than the numerous notifications.I would recommend going with the non-app version which is significantly cheaper. You won't use the app, unless you forgot to set the mode of the unit before leaving on vacation, but even then, what's the worst that will happen? If no one is in your home, it's unlikely there will be any dust being stirred up anyway, and it will just keep running in the previous mode. The app does show air quality in a graph form, but looking at that wore off after the first couple of days.The build quality is really nice. Heavy strong plastic sidewalls, easy and intuitive filter replacement, and it's very quiet for the amount of air it appears to be moving. Overall, I'm very satisfied with the quality!

I love a lot about this air filter. I really like the smart features. I originally thought they would be gimmicky, but after living with it for a few weeks I have experienced the value. I love that it detects the airborne contaminants, and increases air circulation to clean the air. I’ve noticed that it increases air flow during high traffic and vacuuming, among other things. I like that I can check the app for air quality, and I can see past air quality as well. I like that the filter knows when it’s bedtime and decreases airflow, in order to keep noise pollution down, for quiet tearfulness.Now on to effectiveness. We have a nearly 3000 square foot new construction home. It’s about three years old. Most of our air contaminants likely come from area construction, as well as a year round growing season, with year round pollen and similar contaminants. My oldest child has had a persistent hack for the last couple of years. I would not really call it a cough, so much as a hack. Every few minutes he would do a throat and lunch clearing cough. It never seemed short of breath, just seemed to be clearing an irritant. We took him to doctors, who suggested everything from allergies to asthma. We sort of ruled out asthma because he is athletic, and has no issues out working other children, and displays no unacceptable shortness of breath, other than what you expect, and recovery times are quicker than normal. As a previous asthma sufferers myself, that does not resemble asthma to me. We opted to try daily allergy medications, and they seemed to help some, but did not eliminate that dreaded hack. Now I said all of that to say this. Since we added this filter, we hardly ever hear him clear his lungs. I’m actually surprised, because I assumed it would take much longer. I figured he had been doing it long enough that it was a habit by now. But after a few days of filtering, his symptoms diminished, and after a week or so, he almost never does it.Now our home is nearly double the size of the the filters rated coverage area. But the design of our home, I think, allows one unit to work. Our central air unit has only one air return, and it is at the blower unit. This is located centrally, upstairs, in a closet with a vented door. The area around that closet is sort of an open landing area, that opens to a large family room. I think what is happening is that the filter can clean large volumes of air, that then get circulated through the house. The dirty air is then pushed back up to that open area, and filtered by the unit. The unit can tell when air is clean or dirty, and increases, or decreases circulation, accordingly. Anecdotally this seems to be a successful test, eliminating our primary concern. The side benefit is the remainder of our family is now breathing cleaner, healthier air. It just took one sensitive member to illustrate the need. I wish I had known this would solve the problem, and I wish I had done it sooner. I expected to need to units to have a successful result, and I’m so pleased that one unit does the job. Not every home may have the same results. Some may actually need two units to do the job.Also, I opted to shop the amazon warehouse deals and save a bunch of money. I bought a used acceptable condition unit. It arrived in a generic box, but everything was still protected by the factory foam, and cling wrap. Everything appeared new, and worked perfectly. If you want to save s big percentage, I highly suggest checking out the warehouse deals. If your displeased with the condition, Amazon has a very generous return exchange policy. My filters in my unit looked brand new and unused. But if I were concerned, new filters are about $100, so you could still have significant savings, even if you opted to put brand new filters in it right away. At first I was put off by what seemed like a high filter cost. Then I recognized what I was spending on allergy medication each month, for one child. The filters provide clean, allergy free air for the whole family, at a fraction of the cost of allergy medications for one child. By reducing our allergy medication costs, we can replace filters as needed, an no added cost.I would have thought building a new home would prevent these issues, but the other new construction in the area, seems to exacerbate the issue.I also weighed the option of an Aprilair, or air bear system on our central air unit, but I was concerned about the designed air flow for our system, and any disruption could shorten the central air life, increase energy needs, and decrease overall home comfort. Those air filters work great for a system designed and tuned for their use. But for a system designed for a more or less open fiber filter, it could cause problems. So I decided a stand alone filter would be the better option. Also those air handler systems that go on your ariconditioner unit, are not usually helps rated. The AIRMEGA 400s is. And it is constantly monitoring, and cleaning the air. It also uses no harmful ozone. I’m an ozone fan, and I own an ozone generator. But I like to use it in specific situations, under controlled conditions, when all occupants can be out of the house. I don’t want ozone to be a part of my primary home air filtration system. Others may have different priorities, and I encourage you to research the benifits and precautions, and choose according to your needs and priorities.

Update: It’s been over a year and I’ve replaced the filters once. The prefilters require regular cleaning, but the purifiers provide a status light to ensure you know when it is required. These continue to perform extremely well and I remain very happy with their effectiveness at removing dust and allergens from the air.Update: 5/16/2023: Both purifiers I bought continue to perform well. They are quiet and effective. I’m still using the original filters and still have a lot of life left in them, despite leaving them on the smart setting with a medium fan setting 24/7. Excellent purchase for someone dealing with asthma and/or allergies, pets and wanting a well-built air purifier for cleaner air and better breathing.Original review: I have asthma and allergies and have two dogs, and I wanted two well-designed, effective, stylish, large-capacity air purifiers for our great room and the master bedroom. These are very well constructed, easy to use, and effective. They have a set and forget feature that I really like. The pre-filters are easily cleaned with the vacuum brush attachment on your vacuum cleaner and the purifiers provide a cleaning indicator so you always know the status of the pre-filters. The main filters are very well made and are no doubt very effective and long lasting (I have not yet had to replace them and believe they’ll go a year before that is required.) I highly recommend these air purifiers to anyone wanting cleaner air, fewer dust bunnies, and less pet dander in the home. I set them, so they run when needed and shut off when the air is clean. I turn off the light before sleeping and they continue to perform as needed 24 hours a day. I’m very pleased with these and believe they contribute to better health.