Made in the USA NOMMA
36 West Pennsylvania Avenue Walkersville, MD 21793

Custom Fabricated Louvers by Hercules Custom Iron, LLC.

Free Area with Your Louvers

Free Area with Your Louvers

The free area is known as the minimum area in that air can pass through a louver.

Finding the perfect balance between airflow and energy usage is important for building a sound HVAC and exhaust system, and that is where custom louvers come in handy. No building out there is complete without them, but it is very important to know that the way they’re made and installed dictates how well they’ll work. Read on to learn more about free area with your property’s set of louvers from Hercules Custom Louvers!

What Exactly Is Free Area?

The free area is known as the minimum area in that air can pass through a louver. It is simply the total opening spot that is unobstructed by frames and blades. Usually, higher free area will mean improved and enhanced airflow, but it will also allow for better penetration of debris and rainwater.

How to Properly Calculate Free Area

To calculate the free space, take the total open area (remove any obstructions, blade, and frame out from the equation), and divide the figure by the overall opening of the wall. This will help give you a comparison of the louvered openings to the wall openings. Free areas are usually around 35% to 60% of a wall opening. Usually, a bigger percentage is better since much more air can enter through any smaller wall opening, possibly reducing the overall costs. However, this has to be very balanced against a water penetration that a higher free area will likely bring. A well-designed louver set will maximize free space while minimizing any water penetration too.

How Other Louver Factors Impact Free Space Performance

It is very important to remember that free areas all differ by shape, size, screens, and the louvers’ models. These various factors can have a big impact on the free space you get, so make sure you consider all of these factors while picking louvers for your building. A louver that is around four feet wide by eight feet high might not have the same free area as a louver that is eight feet wide by four feet high. Each louver model has different blade shapes and spaces, so they carry the free space for a given size of a louver. If you’d like to learn more about louver-free space and free area before your installation, our professional team at Hercules Custom Louvers will be more than happy to tell you all about it!


When you are ready for quality louvers, the professionals at Hercules Custom Louvers are ready to help. For more information and to learn how we can meet your custom louver needs, contact Hercules Custom Louvers online or giving us a call at 1-800-331-2590. We will ensure your investment serves your property for years to come! For updates and to see projects we’re working on, visit us on FacebookTwitterTwitterYouTube, and Pinterest.

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Hercules Louvers
36 West Pennsylvania Avenue Walkersville, MD 21793
Phone: 1.800.331.2590