Every facility manager knows that one of the most important preventive maintenance tasks is regular filter changes and maintenance. In this video Ryan Hoger with Slipstream provides a quick course in everything you need to know about filter maintenance for rooftop HVAC units.
Obviously commercial rooftop unit filters are a bit different than the filters you have in your furnace at home. The bigger the RTU you have, the more filters you need. You may have “rows and rows” of filters, says Hoger.
How to choose the right filter depends on your goal for the filter. If you just want to keep debris from contaminating the cooling coil, a low-end inexpensive filter should do the job. But if you want to make sure your occupants have healthy air, choose a filter higher on the MERV scale. Hoger says usually about MERV 13 is top-of-the-line and should get the job done.
The highest quality filter is a HEPA filter, which is commonly used in healthcare facilities. But as Hoger mentions, HEPA filters are off limits for a rooftop unit because it creates too much pressure drop for the RTU to handle. isn’t even on the MERV scale – though if it was, it’d be about MERV 17-20.
Hoger then shows how to measure the pressure drop across a filter to know whether it’s time to change a dirty filter. It’s a fairly easy procedure and just requires familiarity with the specs of that particular filter and how to use a manometer.