The short answer
Put it in the room you spend the most time in, a foot or two from walls and furniture, in the path of the room's airflow and near the main pollution source, with the outlet unobstructed. Keep doors and windows closed while it works.
Placement rules
- Give the intake and outlet at least 12 to 18 inches of clearance; 360° units need space all round.
- Raise small units off the floor onto a table if the maker allows; floor-level dust is heavier and settles quickly.
- Place it where air moves: near a doorway or across from the HVAC return helps it mix with the whole room.
- Put it near the problem: the litter box, the entry door in pollen season, the kitchen doorway for cooking odors.
By room
| Room | Best spot |
|---|---|
| Bedroom | Within 6 to 10 feet of the bed, not blowing directly on your face |
| Living room | Central, off the floor, away from corners |
| Open plan | Two units in different zones beat one large unit in a corner |
| Nursery | Out of reach, cord secured, a few feet from the crib |
Avoid
- Corners and behind furniture.
- Right next to a humidifier (moist air loads the filter).
- Directly in front of a heating or cooling vent that blows into the intake.
Products mentioned
Questions readers ask
Should an air purifier be on the floor or a table?
Either works for large floor units; small units clean better raised off the floor.
Does an air purifier work with the door open?
It works, but it's trying to clean the whole house; closing the door lets it clean the room properly.