Once I managed to replace the old filter after nearly a year, this smells fresh again when opened. The ability to keep goods fresh longer is, to some extent the filter to I verdanken.Ob the same result with an activated carbon filter ala hood REAS I doubt it. Too bad that one is from the specialist trade not noted on the purchase of the equipment that you have to relate the replacement filter on the customer service. Fair competition? ... Pustekuchen