When you first start checking your supply air with a thermo-hygrometer, you may notice that the relative humidity is REALLY HIGH. Often, the RH in a supply duct will be between 85% and 96% relative humidity on a system that is functioning as designed. The reason for this is fairly simple: In order for dehumidification […]

Time and time again, low-voltage wiring gets the better of HVAC technicians everywhere. Sure, the wires are color-coded, but that doesn’t mean they’re easy to understand. On top of that, schematics sometimes look like ancient tablets written in hieroglyphics or something. But that’s where HVAC School comes in. There is a new 3D animation video […]

Fan laws and fan curves are a deep subject with a lot of nuance and variation. Just to get our heads around the subject, let's focus on two different types of fans that we see all the time in HVAC: the prop/axial type and the radial/centrifugal type. Centrifugal/Radial As we increase the pressure differential across […]