My husband and I started buying these filters for the house (we live in a rental unit) on a regular basis when we moved in almost 2 years ago. There are 3 air intakes where we replace the filters. Using these filters help me SIGNIFICANTLY during allergy season here in Virginia. They are fine quality filters that do a wonderful job of harboring "the yuckies" that lurk in the air so I don't have to inhale them myself - and they do a great job of overall dust collection so I'm not inhaling that, either!