I have an Aprilaire unit in my home and it was the best thing I ever installed. I suffer from allergens. I had been exposed to harmful air and ended up on disability. These filters are the best! They remove allergens from the air, also dust, pet allergens, etc. you can tell the difference when you replace these filters. I highly recommend changing the filter every 6 months....it keeps your home so clear of the particles that are irritants that are or may be harmful to your health. My home is my safe haven for my health issues, and these filters are a definite asset!