Result
Preliminary calculation: This tool is for quick sizing and information. In real projects, load calculation, selection and commissioning require engineering calculations and a site survey. Results are approximate values.
Formulas
P_electrical [kW] = V̇ [m³/s] × Δp [Pa] / (1000 × η_fan × η_motor × η_transmission)SFP [W/(m³/s)] = P_electrical × 1000 / V̇As filters get dirty, pressure loss increases and fan power rises. Airflow control with a frequency converter and low-pressure-loss components reduce SFP. According to the fan laws, when airflow is halved, power drops to roughly one eighth.
- Filter class and replacement timing directly affect fan energy
- EC fans provide high efficiency at low loads
- Lowering duct velocities reduces pressure and power
Frequently asked questions
What is SFP?
Specific fan power; the electrical power consumed per unit of airflow. A lower value indicates higher efficiency.
How can I reduce fan power?
By reducing pressure loss (clean filters, low velocity), choosing a high-efficiency fan/motor, and adjusting airflow to actual need.
Why is a belt-driven system worse?
The belt-pulley transmission creates extra loss; direct-drive EC fans do not have this loss.