How often should I change filters?

It will depend largely on the size of your building, how many people work there, the type of filter you specify on maintenance, and what you do. In an ideal world, you would change a filter when it is full of things filters catch. You would need to measure the drop in pressure across the filter telling you it’s full with a monometer, however, most commercial air handlers are not equipped with these devices. So filters are typically scheduled to be changed when you’d anticipate they are full of dirt and other stuff filters catch.

This would be quarterly for standard “throwaway” media filters, although in high-traffic areas once or twice a month may be necessary. You may have to adjust this schedule if your filters get dirty faster. If you are using pleated high-efficiency filters MERV 7 or higher to improve indoor air quality, you might be able to go longer between changes. Your commercial HVAC Company should advise you for each system in your building as to the right schedule to maximize your investment in filter changes.