How long do the filters last?
A Corsi-Rosenthal Box operating on low for a portion of a day (such as the length of a typical school day) may last as long as 5 to 6 months before the filters need to be changed. The lifetime depends on how long it is used each day and how dusty the environment is where it is placed. Over time, the white filters will become discolored – typically a light brown to gray – as particles collect on them. If the particles become so thick you can no longer see the white filter media, it is time to switch off the fan and dispose of the filters. All recipients of these units will receive a care sheet that explains how to replace the filters (it's easy!).