HVAC Engineering
The AHU sizing mistake that shows up six months later
Selecting an AHU from a catalogue instead of the heat load produces a system that runs, and fails validation.
- Published
- Reading time
- 1 min
- Written by
- Airvon engineering
An AHU sized against nameplate capacity rather than a calculated heat load and air-change requirement will often pass commissioning and still fail performance qualification months later, once occupancy, equipment heat gain, and seasonal extremes are all live at once.
The fix is sequencing: heat-load calculation first, air-change requirement second, AHU selection last. Every downstream number (duct sizing, filter staging, fan static) inherits from that order, not the reverse.