Concerns about environmental pollution have focused increasing attention on cabin air filtration. This paper examines a new filter tester designed to test the resistance and penetration of cabin air filters made with electrostatic media. The production-style tester uses a NaCl challenge aerosol to perform an automated test at flow rates up to 200 cfm. The machine design and function are discussed, with particular attention paid to the large size of filters and high flow rates. The measurement variability of the tester is examined. Resistance measurements are found to be very repeatable, while penetration measurements of the electrostatic media show more variability.