This photo is of a blower door test we performed at my own house using a Retrotec blower door. You will notice the 15-passenger van outside the window, which is a dead giveaway. A blower door is used to measure the tightness of a building and is often discussed in terms of an ACH50 number. […]

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 […]

How many times has the following situation happened to you? You're on your way to that final service call. While you're listening to the customer explain their complaints over the phone, there's this precise moment where you've thought: “I know what it is already. This will be a quick one.” Sometimes, intuition proves to be […]