Austin Air Pet Machine air purifier replacement filter. Replacement filter includes a medium particle pre-filter, 15 lbs of a specialty carbon/zeolite blend and 60 sq. ft. true medical grade HEPA filter. Available in black and white colors. Austin Air offers a 5-year pro-rated filter warranty, by far the most comprehensive in the industry. No more costly filter replacements every few months or even years. Austin Air filters are designed to last for an amazing 5-years, under normal residential use.