Psychrometrics, Humidity & IAQ

Sometimes I beat around the bush too much in these tech tips, so let's get down to the nitty-gritty! (As Nacho Libre would say.) Humidity inside a home should be maintained between 30% and 60% relative humidity. I like to shoot for 50% in humid climates when possible (and by possible, I mean financially feasible […]

MATLAB Handle Graphics It was December 5th, 1952, only seven years after the end of WWII, in London, England, when the “Great Smog” settled across the city. The “great smog” was the result of a meteorological anomaly combined with unchecked industrial pollution. Still, even once it settled on the city, bringing business to a screeching […]

Let's first state the obvious. Most techs are intimidated by psychrometric charts and Mollier diagrams. We JUST ARE. While there are some pretty complicated formulas that back up these diagrams, using them isn't that big of a deal once you understand the different elements and then focus on one at a time. BUT WHY DO YOU […]

This tech tip about humidity control, particularly as it relates to VRF systems and others that use inverter technology, is a companion piece to a podcast episode with Roman Baugh. You can listen to that podcast episode HERE. Those of you who work in humid climates and install or repair ductless systems are probably well […]

Every once in a while, especially on humid days, you’ll sit on an airplane waiting for takeoff and see fog pouring from the ceiling vents like a low-budget concert. Someone always panics and asks if something’s on fire. It’s not smoke—it’s condensation. You’re looking at thermodynamics and psychrometrics in action. So, why does it happen, […]

I admit it, I'm a sauna guy now. The ones at the gym are pretty gross, so I got a small one at home because I guess I’ve missed sitting in attics or something. If you’ve ever sat in a traditional sauna, you know the drill: the heat’s already intense, and then you or someone […]

In HVAC, we have a few infamous indoor air quality monsters that bring terror to our customers’ homes—gases, particles, and organisms that wreak havoc on indoor air quality (and may contribute to moderate to severe health problems). The big one is carbon monoxide (CO), which we all know is deadly. Although not deadly by itself, […]

This tech tip about traditional and desiccant dehumidification is based on a conversation with Nikki Krueger and David Schurk. Nikki is a longtime contributor to HVAC School and is a relatively frequent podcast guest and symposium speaker. David Schurk is the Director of Applied Engineering and National Sales Manager at Innovative Air Technologies. Nikki specializes […]

This dehumidification tech tip was written by Tim De Stasio. He originally published it on his website, which you can visit HERE. Thanks, Tim! In March of 2024, I set out to better understand the cost of ownership and return on investment for two dehumidification strategies: a dedicated dehumidifier versus using electric reheat dehumidification from […]