Tech Tips:

Does Mass or Volume Move Heat?
By:Bryan Orr I once heard someone say, and have since repeated many times that BTU's ride on the back of Cubic Feet of Air or CFM. As I've learned more I've come to the conclusion that the weight or mass of the air passing over the evaporator coil is far more important to understand both […]
Read more
ECM, VFD, and Inverter – What’s the Difference?
Ever since Nikola Tesla invented the modern induction motor, we have been struggling with varying the speed of motors efficiently and reliably. The trouble in the HVAC industry is that there are several different types of technologies in play, and they can easily get confused. ECM (electronically commutated motor) In residential and light commercial HVAC, […]
Read more


Analog vs. Digital Sine – Short #179
By:Bryan Orr  In this short podcast, Bryan breaks down the differences between analog and digital sine waves. Analog readings deal with an unlimited number of values; they are very precise and can have any number of decimals. As a result, the alternating current (AC) analog sine readings have very smooth curves when we read […]
Read more

Users with Tag #VFD


To continue you need to agree to our terms.

The HVAC School site, podcast and tech tips
made possible by generous support from