I know I’ve said this a lot: A duct can’t be too big. But something can…
Posted on:
Member Exclusive Content
Login & continue reading at acca.org »
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.
Manager of HVAC Design Education at ACCA
Ed Janowiak is ACCA's Manager of HVAC Design Education and can be reached at ed.janowiak@acca.org or 703-824-8878.
Latest posts by Ed Janowiak (see all)
- Hey Ed, should all condensation lines be insulated? - January 21, 2026
- Hey Ed, are the capacities in the AHRI ratings good for anything. - January 14, 2026
- Hey Ed, should the suction line of an operating air conditioner be sweating? - January 7, 2026
Posted In: Aside, Building Performance, Manual D
