What is Louver Free Area?

The louver free area represents the percentage of the louver’s face area that is open and allows airflow. It’s a critical value, as it impacts the efficiency and energy use of HVAC systems. Knowing the free area percentage ensures that air can move through the louver as intended, maintaining effective ventilation.

Formula for Calculating Louver Free Area

To calculate the free area percentage of a louver, use the following formula:

$\text{Free Area Percentage} = \left( \frac{\text{Total Open Area}}{\text{Overall Face Area}} \right) \times 100$

In this formula:

• Total Open Area is the actual open space in the louver (the sum of the spaces between blades).
• Overall Face Area is the total area of the louver face, including both open spaces and structural parts (height x width of the entire louver).

Example Calculation

Let’s say you have a louver with a total face area of 500 square inches and an open area of 300 square inches. Using the formula:

$\text{Free Area Percentage} = \left( \frac{300}{500} \right) \times 100$

$\text{Free Area Percentage} = 60\%$