When it comes to air purifiers, the best place to put them depends on the size and type of device. Large air purifiers are powerful enough to clean the air in a room and can be placed on the floor. Smaller air purifiers, however, should be placed near you, on a desk or table. This is because they don't need to suck in air from below and will work better in a higher position.
Theoretically, the ideal location for an air purifier is close to the door and 3-5 feet off the ground. In practice, it's often easier to put a small air purifier on a desk or mount it to the wall. The Medify MA-35 is a great choice for classrooms, as it has a high Clean Air Delivery Rate (CADR) of 290. You can read more about it in our article on the best wall-mounted air purifiers.
Air purifiers work best when placed in open areas, such as near a window or door. This is because they need plenty of air to clean effectively. Whether an air purifier can be placed on the floor, on a table or on the wall depends largely on its design. Some devices are large and heavy and come with wheels, so it doesn't make sense to put them on a table.
If you're using an air purifier at night, make sure that its low CADR setting is sufficient for the size of your room. For air purifiers that release clean air at the top or front, make sure you face yourself or any pollution sources towards them. The CADR indicates how much air is filtered in one hour for three particular pollutants (smoke, pollen and dust) in cubic feet per minute (CFM). To determine which room in your home has the worst air quality, use an air quality monitoring device such as the IQAIR Air Visual Pro Air Quality Monitor (available on Amazon).
Once you know which room needs the most help, you can place your air purifier there for maximum efficiency. By placing an air purifier 3-5 feet above the ground, you can capture both horizontal and vertical air movement. To ensure optimal airflow and air purification, keep your device at least 2 feet away from other objects from where it draws and releases air. Additionally, make sure that your device is not placed in a very humid area such as a bathroom or closet, direct sunlight or near appliances. For maximum efficiency, place your air purifier as close as possible to any pollution sources and face yourself or them towards it.
With HEPA air purifiers that have a fan and filter, my reserves increase even more. By understanding the need for cleaning and addressing air pollution accordingly, you can ensure that your home has clean and healthy air.