Flex Ducts: Peeling Back the Layers
A few times in the past, we’ve heard the phrase “the house is the biggest duct” because of the way air moves through it. Well, we can take it a step further and see that there are similarities that go just beyond air movement. A building has several layers to keep things like moisture, heat, and […]
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Flex Ducts – Best Practices
Some techs and contractors swear that flex ducts are an evil invention and should never be used in ANY circumstance. I agree with what duct design legend Jack Rise said on the podcast a few years ago when I asked him about flex ducts: “There's a lot of problems with flex duct, there really is, and […]
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Not All CFM Are Created Equal
We’re in the business of moving heat, but we have to move air to accomplish that. We use CFM (cubic feet per minute) to quantify the air we move over the indoor coil, and it helps to imagine hundreds of 1’x1’x1’ boxes of air moving over that coil each minute. (After all, 400 CFM is […]
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Equipment Changes, Ducts are Forever
I’m installing the HVAC system for a house that is being completely gutted. It has vaulted ceilings throughout, and a small attic area was designated for mechanicals. The duct system can’t go in the attic because there basically isn’t one. The engineer intended the equipment to go in the attic mechanical space, and then the […]
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Make Plenum Pressures Work for You
There are several neighborhoods in my area with two—and three-story townhomes with zoning, and I always wonder how long those systems will survive. Zoning can be notoriously hard on HVAC equipment if not set up properly. A single-stage system running full tilt with half the airflow it was designed for because a zone is closed […]
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The One Duct Leak You Didn’t Expect
Sometimes, you just get lucky. Sometimes, you get sent out to install a unit in a closet! Although these types of installs have their challenges, at least for me, they have appeared easier on the surface. There is no return ductwork, as the unit sits on a platform. We are rarely disconnecting ducts in the […]
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Static Pressure, Manometers, and Magnehelics
When you start talking airflow, it can get pretty in-depth pretty quickly. There is a big gap between what is useful for the average tech to apply every day and the whole story, so let's start with the simplest part to understand: static pressure. Static pressure is simply the force exerted in all directions within […]
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When Ducts Get Too Big
This tech tip recaps the livestream by the same name, featuring HVAC School contributors Matt Bruner and Adam Mufich, as well as special guests Russ King, Steve Rogers, and Tony Amadio. You can watch that live stream on our YouTube channel HERE. It was a beautiful day outside. The sun was shining, the birds were […]
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Making Duct Systems Work
This tech tip recaps the livestream by the same name, featuring HVAC School contributors Matt Bruner and Adam Mufich, as well as special guests Ed Janowiak and David Richardson. You can watch that live stream on our YouTube channel HERE. It’s one thing to install a piece of equipment, but it’s another thing entirely to […]
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