Duct Calculator
Optimize your HVAC design with the ThermoFlowPro Duct Calculator. This professional-grade tool allows engineers to size air ducts accurately based on flow rate (CFM), air velocity, and friction loss. Whether you are designing for constant volume or variable air volume (VAV) systems, our calculator provides instant results for rectangular, round, and oval ducts, ensuring your ventilation system operates efficiently and quietly.
Version : 1.0.2
Key Calculation Methods
Equal Friction Method
The most widely used method for sizing supply, return, and exhaust ductwork. Our tool helps you maintain a constant friction rate (e.g., 0.1 in. w.g. per 100 ft) throughout the system to balance airflow.
Velocity Reduction Method
Ideal for residential and simple commercial designs where keeping air noise to a minimum is a priority. Set your maximum velocity limits, and let the tool calculate the required duct dimensions.
FAQ
- Q: What is the standard friction rate for duct sizing? A: A common industry standard is 0.1 in. w.g. per 100 feet of duct length, balancing fan power and duct size.
- Q: Why is aspect ratio important? A: Keeping the aspect ratio (Width:Height) close to 1:1 or less than 4:1 reduces friction loss and saves material costs.