THE FILTERQUEEN HAS A DEFLECTOR SHIELD WHICH HELPS THE MACHINES CENTRIFUGUL FORCE. SO INSTEAD OF THE DIRT BUILDING UP ON THE FILTERS ITS MAINTAINED ON THE OUTSIDE. THE ONLY REASON THE FILTERQUEEN WOULD BLOW DIRT IS DUE TO USER FAILURE. IMPROPER PLACEMENT OF FILTERS, AND NOT USING THE MEDI-FILTER. (THE MEDI FILTER HAS A FILTRATION LEVEL OF 99.98% EFFICIENY AT 0.1 MICRONS.) THIS IS BETTEER THAN HEPA. I HAVE SEEN A LOT OF MACHINES, AND NONE AS GOOD AS FILTERQUEEN.