Generator Enclosure Ventilation Calculator
Cooling airflow for an enclosed standby generator.
Enter your values
ⓘ Live results
Results
- Estimated total heat load
- 716,520 BTU/hr
- Required ventilation airflow
- 33,172 CFM
- Note
- Includes ~40% margin over electrical output for engine/alternator losses
Quick answer
Generator enclosures need airflow to remove both radiator heat rejection and alternator/engine surface heat, typically several times the engine's own radiator fan flow.
CFM = total heat rejection / (1.08 x allowable dT)
How to use the Generator Enclosure Ventilation Calculator
- 1Take the generator's rated electrical output in kW.
- 2Apply roughly a 40% margin to account for engine and alternator heat losses beyond electrical output.
- 3Divide by 1.08 times the allowable enclosure temperature rise to size louvres and fans.
Worked example
Using the values the calculator loads with:
Inputs
- Generator rated output150 kW
- Allowable enclosure temp rise20 F
Results
- Estimated total heat load716,520 BTU/hr
- Required ventilation airflow33,172 CFM
- NoteIncludes ~40% margin over electrical output for engine/alternator losses
Frequently asked questions
Does the radiator fan handle this alone?
The engine radiator fan handles coolant heat, but enclosure ventilation must also clear residual heat around the whole unit.
Louvre sizing?
Intake louvres should be sized generously (low face velocity) to avoid restricting the radiator's own airflow.
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.