The fact sheet for a case study on the economics of installing an air filtration system that looked at seven barns. Four barns were farrowing facilities, two were for replacement gilts, and one was a farrow-to-finish. The capital outlay costs were the initial material and labor needed to install the system, and maintenance costs were the initial and replacement filter purchases, as well as the labor needed to change filters. The study looked at the costs for changing filters every three or every five years. Costs varied between barns, and were largely dependent on the initial preparations needed to install the system, and the amount of ventilation required. If over ten years the air filtration system prevents 1.5-4 PRRSv outbreaks in a farrowing facility, or any outbreaks in a gilt replacement facility it provides an economic saving.