#duct design

Tech Tips:

Make Plenum Pressures Work for You
By:Matthew BrunerThere 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 […]
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When Ducts Get Too Big
By:Bryan OrrThis 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 […]
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Making Duct Systems Work
By:Bryan OrrThis 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 […]
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Manual J Field Data: Ducts
By:Matthew BrunerUnderstanding the relationships between ductwork, home comfort, and the load on a house is a complicated and dynamic problem. There are a large number of variables. Some of the data is fairly straightforward, like the other elements of field data collection we have covered so far in this series. Ductwork has different levels of […]
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Sizing Return Grilles
By:Matthew BrunerA few weeks ago, I spent several days redoing a duct system and replacing a furnace for a friend. I had static pressure readings from before the system was replaced, and with the new furnace that I had picked out, I had created a static pressure budget and felt confident I could significantly lower […]
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Equivalent Length Merry-Go-Round
By:Adam Mufich I recently read a tech tip by Matt Bruner about using the Manual D process. In the article, he designed a duct system for a small job using a ducted mini-split. One thing I noticed about his design was that the supply and return duct velocity was fairly low compared to the arbitrary […]
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Plenum Takeoffs Best Practices
By:Matthew BrunerIn my second year in HVAC, I went out with a senior technician to install a supply duct for a bathroom in a house. While he ran the duct, I cut a hole in the plenum and attached the collar. He crawled back across the attic and very nicely told me that people don’t […]
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Manual D Speedsheet Walkthrough
By:Matthew BrunerBryan recently released a podcast on rules of thumb and how they can really get us in a pickle with sizing ductwork. With that in mind, I thought this might be a good time to do a walkthrough of Manual D from start to finish on a project I just finished up. My good […]
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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 expert Jack Rise said on the podcast when I asked him about flex ducts: “There's a lot of problems with flex duct, there really is, and it's a good product, […]
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Podcasts:

Common Duct Design Mistakes w/ Jack Rise (Podcast)
By:Bryan Orr In this episode, Jack Rise talks about duct design regarding ACCA manual D, friction rate, face velocity, duct velocity, and what is ACTUALLY wrong with flex duct. Manual D causes a lot of confusion for technicians, and most techs have a limited understanding of it anyway. When determining a blower wheel for commercial […]
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Events:

A Duct Up Situation
By:Sam MyersEric Kaiser  NOTE: If you cannot view the recording, the video may still be processing. The maximum wait time is 24 hours. We apologize for the delay and appreciate your patience.
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Friction Rate. Why the Fuss? (WTF)
By:Russ King NOTE: If you cannot view the recording, the video may still be processing. The maximum wait time is 24 hours. We apologize for the delay and appreciate your patience.
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