Server Room Exhaust Calculator
Exhaust/supply airflow for a small server or IT closet.
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ⓘ Live results
Results
- Required airflow
- 948 CFM
- Heat load
- 10,236 BTU/hr
- Recommendation
- Consider dedicated cooling (CRAC/mini-split) instead of ventilation alone
- Redundancy
- Critical rooms should have N+1 cooling, not ventilation alone
Quick answer
Small server rooms without dedicated CRAC units can sometimes be cooled by ventilation alone if the heat load is modest, using CFM = watts x 3.41 / (1.08 x allowable rise).
CFM = (watts x 3.412) / (1.08 x allowable temp rise)
How to use the Server Room Exhaust Calculator
- 1Total the IT equipment's electrical load in watts (essentially all becomes heat).
- 2Choose an allowable temperature rise, typically 8-10°F.
- 3For loads above roughly 500-1000 CFM equivalent, dedicated mechanical cooling is safer than ventilation alone.
Worked example
Using the values the calculator loads with:
Inputs
- IT equipment load3000 W
- Allowable temperature rise10 °F
Results
- Required airflow948 CFM
- Heat load10,236 BTU/hr
- RecommendationConsider dedicated cooling (CRAC/mini-split) instead of ventilation alone
- RedundancyCritical rooms should have N+1 cooling, not ventilation alone
Frequently asked questions
Can ventilation alone cool a server room?
Only for small loads with a reliable, cool air source — most server rooms need dedicated, redundant cooling to protect uptime.
What temperature should the room be?
ASHRAE recommends 64-80°F (18-27°C) at equipment intake for most IT gear.
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.