🎯 Why It Matters
Airflow is the primary metric for cooling capacity. Higher CFM = more heat removed. But airflow alone is misleading — always consider the system's static pressure. A fan's free-air CFM (zero back pressure) drops significantly when installed in an enclosure or duct.
📐 How to Read
Always check CFM at the expected operating pressure, not free-air. Fan curves show CFM vs static pressure. The actual operating point is where the fan curve intersects the system resistance curve.
📏 Typical Values
Small electronics: 2-20 CFM. Server/telecom: 50-200 CFM. Industrial cabinets: 200-1000 CFM. HVAC ducts: 500-5000 CFM.
🔗 Related Parameters
Static Pressure, Fan Curve, System Resistance, Noise Level
❓ Frequently Asked Questions
Is higher CFM always better?
No. Excess CFM wastes energy and increases noise. Size airflow to match the enclosure's actual heat load. A fan rated 100 CFM in free air may only deliver 40 CFM when installed behind a filter — always account for pressure drop.
How do I convert CFM to m³/h?
Multiply CFM by 1.699 to get m³/h. For example, 100 CFM = 170 m³/h. For rough estimates, you can use CFM × 1.7.
Why does installed CFM differ from rated CFM?
Rated CFM is measured in free air with zero back pressure. When installed, grills, filters, and enclosure resistance create back pressure that reduces actual airflow. Always derate by 30-50% for filtered enclosures.