Psychrometrics, Humidity & IAQ

This tech tip recaps the livestream by the same name, featuring HVAC School contributors Matt Bruner and Adam Mufich, as well as special guests Corbett Lunsford and John Semmelhack. You can watch that livestream on our YouTube channel HERE, and you can learn more about the great educational opportunities Corbett has to offer at https://buildingperformanceworkshop.com/. […]

This tech tip is a recap of the Santa Fe Dehumidifiers and Comfort Dynamics, Inc. case study about a 1941 vintage home in Miami, FL. You can listen to the podcast about that case study by clicking the play button below, and you can read the case study at https://hvacrschool.com/case-study. Special thanks to Nikki Krueger […]

Have you ever been tasked with installing the exhaust duct for a kitchen hood?  I have, and when doing so, I wondered how to size the duct run correctly. Since I had a basic understanding of how airflow works, I knew that there had to be a limit on the resistance the fan can handle; […]

This tech tip was submitted by Steve Rogers, the current president of The Energy Conservatory (TEC). Steve has been on the podcast several times in the past and is a valued contributor to HVAC School. Thanks, Steve! As summer approaches, HVAC technicians all over the US are preparing for those difficult conversations with occupants about […]

Water is weird and water vapor is even weirder – before we dive down this rabbit hole lets define some terms To better understand the behavior of moisture in materials, we need to first define some essential terms and concepts: Relative Humidity (RH): The ratio of the amount of water vapor in the air to […]

Air conditioning was about humidity control from the very start. Willis Carrier’s very first air conditioning system was all about controlling the humidity with the side effect that it also could reduce the sensible temperature. Theaters caught on that this newfangled contraption could lead to big summer numbers when they installed it to keep patrons […]

Photo by Stephen Rardon I hear it all the time. Someone will talk about undesired condensation on an air handler cabinet, on a supply air duct, in a ventilation duct, or on a vent like the one above. In reply, someone will inevitably say, “Condensation occurs where hot meets cold.” Early on in my career, […]

I’m not sure who first started calling evaporator coil odors “dirty sock syndrome,” but I really wish they hadn’t. Nowadays, every tech out there can’t help but categorize every odor from the system as “dirty sock syndrome,” and customers just LOVE to hear that they have a “syndrome” named after a dirty locker room smell. […]

I recently received a message asking for a discussion of relative humidity (RH), wet-bulb (WB), and dry-bulb (DB). Time and time again, I hear techs say that condensation occurs when “hot meets cold,” which may be true in some cases. However, that is only a shorthand way to describe it and doesn’t really address what […]