Quiet and well worth the investment. I've seen a noticeable improvement in the air quality in our home. I live in Florida and have asthma and allergies and this air purifier definitely makes a difference when it comes to my health. Love it so much we are planning on buying the larger unit for the rest of the house.
It works ok but when the display light is turned off and the unit is set to auto, it doesn’t automatically adjust until the display light is turned back on. Not sure if it’s supposed to work that way or there is a defect.