Coil Sizing Calculator

Size heating and cooling coils for AHUs from airflow and temperature requirements.

Air Conditions

Coil Configuration

Coil Capacity
--
BTU/hr
Face Area Required
--
sq ft
Capacity (Tons)
--
Actual Face Velocity
--
ft/min
Est. Pressure Drop
--
in. w.g.
Suggested Coil Size
--

Coil Sizing Basics

Face Area = CFM / Face Velocity

Sensible Capacity = 1.08 x CFM x (EAT - LAT)

Total Capacity = 4.5 x CFM x (h_entering - h_leaving)

  • Face velocity: 400-550 fpm for cooling coils, up to 700 fpm for heating
  • Rows: 3-4 for comfort cooling, 6-8 for process cooling
  • Fins: 8-14 FPI; higher fin count = more capacity but more pressure drop

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