I had to put a new furnace in my house a couple of years ago and opted for the heavy duty hepa type filter set up. I have noticed a distinct improvement in the amount of dust laying around the house. The furnace has a two stage fan motor so when not heating it is still circulating all the time. I really like that set up. My furnace guy said it recirculates all the air in the house every hour or so.

DS
Northern Iowa