3m airstream hepa filter

[joe zarnitz]

how often do you need to change---tks.joe

[Steve Schlumpf]

Joe - it really depends on the environment that you are using the airstream. I use mine for everything woodworking - not just turning - and only change the filter every 2 to 3 years. When I got my airstream - it came with a small piece of cardboard that is designed to fit over the air intake and let you know if the filter is operating efficiently. I use that as well as elapsed time to determine when to replace mine.

[Bill Boehme]

There's a little round plastic disk with a rectangular hole. Remove the pre filter and place it over the air intake with the unit running. If there is enough suction to keep the disk from falling then the filter is OK. It seems like I go a couple years or more before needing to replace the filter.