How to Measure Air Filter Static Pressure Drop

Start by zeroing out the sensor on the Testo Smart Probes mobile app. The probe on top of the filter should be on the negative side of the Testo 510i, and the probe on the other side of the filter connects to the positive side to help measure the static pressure drop across the filter.

In our case, the pressure drop was 0.13″wc (inches of water column). Given that the filter was a MERV 11 type, that static pressure drop was considered normal.

Testo: https://www.testo.com/en/