We have tested more than 50 air purifiers in the past nine years and our measurements have shown that the exceptional Coway Airmega AP-1512HH Mighty is the best of them. It is powerful enough to be used in a large room, quiet enough to be used near sleeping areas, designed to last for years, and inexpensive enough to install in multiple rooms. The Coway Airmega 200M is virtually identical to the Airmega AP-1512HH Mighty in every important way. They are equivalent in terms of noise and performance measurements, their filters are interchangeable, and their similar controls allow you to turn off the lights on the screen.
The 200M has a square grill instead of a round one, but that's the only important physical difference. If you prefer the look of the 200M or find it at a better price, we recommend it. Levoit's Vital 200S matched Coway's Airmega AP-1512HH Mighty in performance tests, and both are very similar in terms of energy efficiency, noise emission, and the ability to turn off the screen while maintaining the fan configuration of your choice. However, the Vital 200S is a new version (from January 2), so we haven't had it yet time to test it in the long term.
In conditions where air quality is poor, such as when your area is affected by a nearby wildfire, we recommend running air purifiers at a high temperature for one hour and then running them in a quiet environment or medium to create and maintain clean air in the home. After burning 15 wooden matches (to create an initial heavy load of fine smoke particles), we tested this method with the Coway Airmega AP-1512HH Mighty and the Airmega 400 for three hours, one hour at high temperature and two at medium temperature. One of the smallest models available for air purification in large rooms is the cylindrical design that allows 360-degree air collection; it has a low-volume option with bells and whistles with high efficiency, low to moderate noise, and a customizable pre-filter cover that's available in five different colors to suit your environment. Your air purifier recirculates the air that is already in the room and cleans it by passing it through a filter where microscopic solid particles are removed.
If you try this trick, carefully seal the filter around its entire perimeter with clear, sturdy adhesive tape (any space would have let unfiltered air through), just like in dedicated air purifiers. If the humidity is too low, dust levels rise and dry air irritates the nose and throat, so humidity control and air purification are closely related. Blueair recommends replacing the filter “every six months or so”; it's best to stick to that schedule. Unlike other options on this list, this Bissell air purifier looks more like modern furniture than an air purifier.
These include a toxin filter that offers a 34% improvement over the standard filter by removing chemicals from the air and a filter for pet odors. However, in its average configuration, the Air Mini+ still consumes more electricity than the Coway Mighty, which is much more powerful (our best choice between purifiers and a machine capable of keeping air clean in a much larger space). While the 300 may not have the advanced digital features that some competitors have, it's an excellent air purifier for its price, especially considering its ability to adapt to different use cases with alternative filter types. If you have allergies or are simply concerned about the air quality in your home, a HEPA air purifier can help you.
Purifiers work best in an adjoining space; if you want to clean the air in both the living room and a bedroom, for example, it's best to buy a purifier for each room or carry one with you.