Coway Airmega 240 True HEPA Air Purifier

I bought a 230 in Sage Green in September of 2023, around the time they first released. It has been running 24/7 at speeds 1-2 since then, with negligible stopped time. I have been pleased with it, so I finally bought a replacement filter for that one in April 2025 (approximately 18 months on a single filter) and purchased another 230. Long story short, this air filter has proven reliable, appears to be reasonably (and anecdotally) responsive to changes in air quality, is aesthetically pleasing, and is easy to maintain. Cost of entry is fairly low, and cost of operational maintenance (time, ease, filter cost) is also comparatively low. I currently run two of these Coway 230's and a Blueair 680i for a 1250 sq.ft (116 m²) apartment. Adjacent units' air leaks into our unit (shared compressor and vent), which means food odors, tobacco (and "other") smoke, and sometimes mildew/mold. The building was built in the 1970s, and there are issues with leaking roofs, poor ventilation in the underground parking, etc. We also have cats, which means litter dust, litter smell, and hair/dander. Of course, we also produce our own air pollutants, like cooking odors or aerosolized products. The Coway has done very well in whichever room it's in, reducing odors and dust. It's fairly quiet at all speeds, although 3 is the maximum fan speed and is loud, though not at all intolerable. There have not been any unusual noises, like squeaks or vibrations. The pre-filter is easy to clean with a vacuum or with water, and helps keep the primary filter media free of large debris like clumps of cat hair. The filter media itself is very large and has a lot of pleats, which means more surface area, for lower load on the blower (more efficient and less energy consumption) and more overall filtration capacity (longer overall life before loss of efficiency). Compared to the much larger Blueair, there are some observations that people may like to know: The 680i is significantly larger, designed to perform five air changes per hour for a 770 square foot (72 m²) room. That means that even at the lowest speed, it will generally outperform the Coway, which can perform the same number of air changes in a 403 square foot (38 m²) room. I believe that most air purifiers measure their air changes at the highest blower speed. A larger unit will have a larger blower, which means running the 680i at the lowest and nearly silent speed will still be moving as much air as the Coway at the maximum and loudest speed. For those sensitive to noise or with a need to minimize ambient noise, it may benefit you to oversize the filter for your application. The prefilter is a win for Coway. I have to vacuum the filter in the Blueair monthly to make sure it's not blocked up with debris. It can be heard as buffeting at the blower output. The cats like quality time in the bedroom, so there's always hair. While I haven't cut up the Blueair filter, it is dimensionally smaller than the Coway filter. One may cautiously assume that they deliver equivalent performance as they are both HEPA. This is not an accurate comparison of filter efficacy, since surface area and static pressure, and as a function of those, dwell time of air through the filter is a good measure of filter performance. Basically, I like big filters with lots of frontal surface area. Coway draws air through almost the entire front face. The Blueair draws air from one side to the other, which means a smaller filter intake area. The Blueair body is made of die stamped, powdercoated steel. It's heavy duty and durable, but weighs at least twice the Coway. It even has casters. Durability of the housing may not matter to you, but the Coway is a bit flimsy. This is not a concern to me, but something you may want to consider. The Blueair is a clamshell design, and when you open the rear side, it swings out so you can access the filter and interior. To replace the filter in the Coway, you pop off the front shell. It's easy, but the clips are plastic and the shell is flexible, perhaps too much so. If you were to be clumsy, you may damage it. The air quality indicator on the Coway is extremely bright. It can be switched off, which is a considerate feature. The Blueair lacks this. However, it's nothing a bit of tape can't fix. The smart function on the Coway will run the blower at an extremely low speed or it will shut off if the air is clean and has stayed clean for a long time. The Blueair will run continuously on the lowest speed.