How to Calculate Furnace CFM for Electric Heat
To calculate the CFM for an electric furnace, use the following formula:
CFM = (Volts × Amps × 3.41 × Efficiency) / (1.08 × ΔT)
Where:
- CFM: Cubic Feet per Minute (airflow required)
- Volts: Incoming voltage to the electric strip heaters
- Amps: Current draw in amps to the electric strip heaters
- ΔT: Temperature rise across the heat exchanger in °F
- 1.08: A constant that includes the specific heat of air and the density of air at standard conditions
- 3.41: A conversion factor from watts to BTUs
- Efficiency: Efficiency of the furnace (default is 99%)
Use the form above to input the values, and the calculator will provide the required CFM.