Choosing an Air Purifier by Room Size

An air purifier that is too small takes longer to circulate the air in a room, so its size matters more than its number of features.

Measure the area you actually use

Multiply the width of the room by its length. If the room opens onto another space, include that space as well.

Understand CADR

CADR is the clean air delivery rate. The higher it is, the more filtered air the purifier delivers per unit of time. Compare values tested under the same standard.

Allow a little extra area

A purifier rated for slightly more area than the room can run at a low fan speed, so it stays quieter in everyday use. This matters most in bedrooms.