What does the Air Exchange Rate mean?

The air exchange rate is telling you how quickly an air purifier can clean the air within the desired space. For example, if your IDEAL air purifier states it’s ideal for a room size of 800ft²  with an Air Exchange Rate of 14 minutes. This means it only takes 14 minutes to clean the air in an 800ft²  room. If the machine ran for just under 1 hour, it will clean the air in that 800ft²  room 4 times.