AHU Sizing Calculator
The AHU Sizing Calculator finds the supply airflow, coil capacity, and fan motor for an air-handling unit from its cooling load. Example: for a 50 kW cooling load for a 300 m² space with 40 people, Supply airflow = 8325.1 CFM, Coil capacity = 30.39 TR, Fan motor = 11 kW (per ASHRAE 62.1 | ASHRAE 90.1 | ASHRAE 2021 Ch.1 | SMACNA).
How it works
Computed from your inputs per ASHRAE 62.1 | ASHRAE 90.1 | ASHRAE 2021 Ch.1 | SMACNA.
Worked example (HVAC & Cooling)
Inputs: a 50 kW cooling load for a 300 m² space with 40 people.
| Result | Value |
|---|---|
| Supply airflow | 8325.1 CFM |
| Coil capacity | 30.39 TR |
| Fan motor | 11 kW |
Computed live by WorkHive's calculation engine; standard: ASHRAE 62.1 | ASHRAE 90.1 | ASHRAE 2021 Ch.1 | SMACNA.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a 50 kW cooling load for a 300 m² space with 40 people.
- The calculator returns Supply airflow, Coil capacity, Fan motor, computed per ASHRAE 62.1 | 90.1 | Fundamentals.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a air handling unit sizing calculator CFM?
The AHU Sizing Calculator is a free online tool that computes finds the supply airflow, coil capacity, and fan motor for an air-handling unit from its cooling load. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following ASHRAE 62.1 | 90.1 | Fundamentals. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive AHU Sizing Calculator in WorkHive: free, no sign-up needed for the calculators.