Have used this filter and air purifier for over 20 years. You replace the filter every 5 years. I have year round allergies. My husband and I cannot sleep if machine not on, lulls you to sleep, blocks out other noises. Highly recommend.
The filter is powerful and long-lasting. Using it in a room makes it smell like outdoors on a fresh day.
This is the best filter out there. Under normal conditions you only have to change the filter every 5 years. It works perfectly for cleaning the air in the room.