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Ed Janowiak is ACCA's Manager of HVAC Design Education and can be reached at ed.janowiak@acca.org or 703-824-8878.
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There’s a common misconception in the field that duct sizing is mostly about “keeping ducts small to keep the air moving.” You’ve heard it: “Smaller ducts make the air go where it’s supposed to.” But the truth is, as ACCA Manual T® makes clear, air distribution isn’t about how fast you can shove air through an airway — it’s about delivering the required volume to the supply register.
In this edition of “Hey Ed,” Ed discusses measuring wet bulb ΔT when checking a system.
In this edition of “Hey Ed,” Ed discusses measuring dry bulb ΔT and system performance.
In this edition of “Hey Ed,” Ed discusses the connection between dry bulb ΔT and good system performance.
In this edition of “Hey Ed,” Ed discusses relative humidity across evaporator coils.
In this edition of “Hey Ed,” Ed discusses the correct airflow.
In this edition of “Hey Ed,” Ed discusses the difference between a metal duct and a flex duct when 100 CFM is going through it.
In this edition of “Hey Ed,” Ed discusses the path to size based on AC requirement in Manual S.
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I have mixed feelings about ChatGPT — so I asked it directly. ChatGPT said: That’s a fair and important question. The honest answer is: you can trust ChatGPT for many things, but not everything. Here’s a breakdown:
In this edition of “Hey Ed,” Ed discusses the latest changes to Manual S.
In this edition of “Hey Ed,” Ed discusses the Manual J calculations for bedrooms.
In this edition of “Hey Ed,” Ed discusses placing an outdoor unit under the house.
In this edition of “Hey Ed,” Ed discusses placing an outdoor unit in the shade.
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If moist air is lighter than dry air, basement dehumidifiers seem to defy basic physics. A contractor’s simple question reveals a complex building science principle in this members-only exclusive.
In this edition of “Hey Ed,” Ed discusses Manual D’s requirement of an uninterrupted path for the air to come out of a supply outlet and get back to the fan.
In this edition of “Hey Ed,” Ed discusses the weight of a cubic foot of standard air.
In this edition of “Hey Ed,” Ed discusses the most efficient ways to connect a return duct to an air handler.
In this edition of “Hey Ed,” Ed discusses AHRI SEER 2 operating efficiency in system design.
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