I understand the desire for pets even when you're allergic.

My confusion was that you're looking for the best way to filter the allergen out of the air, when the real solution is to remove the source of the allergen completely.

I understand, though, that you're looking for the best reduction of allergen, given the constraint that you can't simply get rid of your beloved pets.

I just don't see how an air purifier is going to help much. It's like running a vacuum cleaner around the house with no bag attached. Unless you remove the source, you're just shuffling the undesired particles around in the room.