I have had this Air Purifier For Office for almost a year now. It’s still very quiet and the fans run strong. It is running at least 12hrs a day. The black pre-filter only killed odors for about a week. Any replacement pre-filters only work on odors for about a week as well. I just vaccum and wash mine. The main hepa filters are very expensive to replace if you do it every 3 months like your supposed to. I just purchase the largest 3M filters (2 pack) for 18 bucks at Lowe’s. You can cut 5 perfect fitting filters out of one. On the bottom of where you place the filter in is a little trip latch you will need to tape down so it thinks it has an “authentic” filter in it.
