Measuring airflow is easy. Measuring airflow accurately is quite a bit more difficult. In many cases, when we as technicians measure airflow, we are trying to get to the almighty CFM (cubic feet per minute) volume measurement. You can take CFM readings fairly easily with a hood, like the Testo 420, but even a hood […]

This quick tip was written by Daniel Andersen in the HVAC School Group. Daniel was one of my early encouragements to make the podcast, even though he refuses to come on himself. Thanks, Daniel! ERV – What is it?  An energy recovery ventilator allows fresh air from outside to be introduced into the conditioned space […]

Why Defrost? Let's start with the basics and move on from there. Defrost is necessary when the coil temperature drops below 32°F. Defrost can be as simple as turning the compressor off for a period of time or as elaborate as reversing the flow of refrigerant for the whole system or just parts of the […]