Our HVAC Louvre Size Calculator is a convenient and accurate tool designed to help you determine the appropriate size of louvres needed for your HVAC system. By simply inputting the airflow rate (CFM), face velocity (FPM), and free area ratio, this calculator will provide you with the exact louvre size required to ensure optimal air distribution and system efficiency.

Ideal for HVAC engineers and technicians, this calculator simplifies the process of sizing louvres, saving you time and ensuring precise measurements.

Use our HVAC Louvre Size Calculator to streamline your project planning and ensure your HVAC system operates at peak performance.

To use the HVAC Louvre Size Calculator, follow these simple steps:

1. Airflow Rate: Enter the airflow rate in the input box. This is the volume of air flowing through the system. Select the appropriate unit from the dropdown menu:

- Cubic feet per minute (CFM)

- Cubic meters per second (CMS)

- Liters per second (LPS)

- Cubic meters per hour (m3/hr)

2. Face Velocity: Enter the face velocity in the input box. This is the speed at which air passes through the louvre. Choose the correct unit from the dropdown menu. Typical face velocity values for HVAC applications are:

- Feet per minute (FPM): 300 to 700 FPM, with 500 FPM being a common choice

- Meters per second (MPS): 1.52 to 3.56 m/s, with 2.54 m/s being a common choice

3. Free Area Ratio: Enter the free area ratio, which is the percentage of the louvre's total area that is open to allow airflow. This value is usually expressed as a decimal between 0 and 1. In HVAC systems, a common free area ratio is between 0.5 and 0.7, indicating that 50% to 70% of the louvre area is open. The louvre design graphic below the calculator gives a rough idea of the entered free area value.

4. Calculate: Click the "Calculate" button to determine the required louvre size. The calculator will display the louvre size in both square feet (sq. ft.) and square meters (m²), ensuring you have the necessary information for any measurement system.

Click here to read about how to carry out the calculation for estimating louvre sizes.