Refrigeration Condenser Airflow Calculator
Air-cooled condenser CFM from heat of rejection.
Enter your values
ⓘ Live results
Results
- Required condenser airflow
- 1,235 CFM
- Fans at 3000 CFM each
- 1
- Approx condensing temp margin
- 16.2 F above ambient
Quick answer
Air-cooled condensers typically need enough airflow to keep the air-side temperature rise around 15-20F above ambient.
CFM = (THR in BTU/hr) / (1.08 x dT)
How to use the Refrigeration Condenser Airflow Calculator
- 1Get total heat of rejection (compressor work plus evaporator load) from equipment data.
- 2Choose an allowable air-side temperature rise, usually 15-20F.
- 3Divide by 1.08 x dT to find condenser fan CFM.
Worked example
Using the values the calculator loads with:
Inputs
- Total heat of rejection24000 BTU/hr
- Allowable air temperature rise18 F
Results
- Required condenser airflow1,235 CFM
- Fans at 3000 CFM each1
- Approx condensing temp margin16.2 F above ambient
Frequently asked questions
What is total heat of rejection?
It is the evaporator's cooling load plus the compressor's added heat of compression.
Coil fouling?
Dirty coils reduce effective airflow — increase design margin 10-15% for real-world dust and debris.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.