How much noise do air purifiers make?

Internal fans in most air purifiers draw air through a series of filters. Some of these fans are virtually silent, especially when set at low speeds. When you turn them up, they generate a humming sound.

Finding the proper purifier with the right decibel level can be difficult when noise is assessed by both the product's sound pressure and sound power. A normal discussion has a sound pressure rating of 60dB, however, the sound power is 70dB. The sound pressure scale is lower than the sound power scale, and you must know which decibel you are purchasing to have the quietest air purifier possible.

If you're going to use your air purifier in a bedroom or baby's room, for example, you might want to go for one that's pretty quiet even at higher speeds.