Compressibility is the ability of a substance to be squeezed into a smaller volume. It is the change in volume and increase in density that results from an increase in pressure. The subject of compression should be familiar to HVAC techs. After the return air passes over the boiling refrigerant in the evaporator coils, the […]

You may not know this, but the HVAC School podcast began before the website. When I started the podcast, I never intended to create a website, but there was more demand for quick tech tips than the podcast could hold. So, we started hvacrschool.com. In the same way, I never set out to create a […]

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, […]