How to ACTUALLY Measure Airflow w/ Steve Rogers and Eric Kaiser

Steve Rogers from The Energy Conservatory (TEC) joins Eric Kaiser to talk about airflow measurement at AHR 2022. Steve is an expert in fluid dynamics and flow measurement, and he is a trainer in addition to being the president and CEO of TEC.

Airflow is one of the most critical elements of an HVAC system; it allows us to move the correct amount of BTUs to condition the air properly. We have various ways of measuring system airflow and airflow to a space. We can use the TrueFlow grid for the former and flow hoods for the latter.

When it comes to measuring airflow, calibrating the instrumentation is crucial. TEC uses a laboratory-grade orifice plate to calibrate the tools. So, the calibration process manages to yield high accuracy while using a low-maintenance device.

To begin measuring airflow properly, start taking the total external static pressure (TESP) and looking at fan charts. TESP doesn’t actually measure airflow, but it provides an idea of what the airflow might be like, and it’s a practical, useful measurement in the field.

The TEC TrueFlow grid has recently been upgraded, and it’s a good step up from taking the TESP and referencing fan charts. It goes into the filter slot and measures the CFM per ton as well as the static pressure.

Steve and Eric also discuss:

  • Airflow’s effect on latent and sensible cooling
  • Blower door setups and chambers
  • References for accuracy
  • Relationship between static pressure and airflow
  • Is the hand-ometer an acceptable form of airflow measurement?
  • Challenges of pitot tubes and hot-wire anemometers


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