Austin Air filters are designed to last up to five years under normal residential use. The pre-filter, located between the main filter and the outside cabinet, traps large particles during the first stage of Austin Air’s multi-stage filtration process. In doing so, it helps prolong the life of the inner filters, especially the HEPA. A pre-filter can be replaced annually, or less often if it is vacuumed periodically.
Because the pre-filter can be seen through the unit’s grille, the black pre-filter is recommended for black, silver and blue units. The white pre-filter is usually used in sandstone, white, pink and baby blue units.
The same pre-filter is the used in all units: Healthmate, Healthmate+, Pet Machine, Allergy Machine, and Bedroom Machine but the size depends on whether you own a Junior or Standard unit. All Bedroom and Pet Machines are standard size; all Baby’s Breath are junior size. Healthmate, Healthmate+ and Allergy Machines are available in both Junior and Standard sizes. If you’re not sure which size you have, you can measure your filter: Junior measures 11.5” high, and Standard filters measure 14.5” high.