AHU and filter change log

When you need this form

Air handling units need a running history: filters changed, belts checked, coils and drain pans inspected, hygiene observations noted unit by unit. Facility teams use this log on scheduled maintenance visits, after a complaint about air quality, and when a mechanical contractor hands the site over. Building owners carry duties around air hygiene and microbial control, and most states expect records to back them up.

The value of the log is the trend, not the single visit. Photos of a coil across four quarters show whether cleaning is holding. Filter change intervals per unit show whether the schedule matches the site. A logbook in a plant room gives you none of that, and it is usually the first thing lost when the contractor changes.

What good looks like

• Each unit identified by asset number and location, not "level 3 AHU".
• Filter type, size and quantity changed, with the date recorded per unit.
• Belt tension and condition checked, with replacements noted.
• Coil, drain pan and tray condition photographed, including any microbial growth.
• Technician named and signed, with the next service interval set.