The Condenser - Water Infiltration and Louvers

The Condenser - Water Infiltration and Louvers

In this Condenser, we look at the dangers of water infiltration through your louvers. How much damage can it do? Learn more on the MCDLG Newsstand.

Louvers - Protection from Rainfall

Louvers are installed in ventilation intake and exhaust points to protect your HVAC system from damaging elements, like rainfall. Louvers can have a variety of other functions, based on their design, but their primary function is to protect interior spaces from damage. While important, this protection can drag down system performance.

Protective features, like drainable troughs and catches, can make it more difficult to pass air through the louver. Why not choose a louver with smooth blade profiles? Can you get away with using a non-drainable louver? What happens when water infiltrates your HVAC system?

Two straight blades demonstrating water penetrationA smooth straight blade can work in light rain. You will need more blade features to protect against heavy rain and severe weather.

The Dangers of Wate Infiltration

Remember that louvers are often installed in hard-to-reach places. They aren't always easy to access and maintain. Even a small amount of water can damage ductwork, if left unchecked over time. Water damage can take two forms in your duct: rust and mold. You won’t have to worry about your extruded aluminum louvers, but other metal components may rust when subjected to water. This can include the hardware used to fasten the louver to its opening.

Do you have severe weather requirements for HVAC? Consider adding severe weather louvers from Arrow United Industries. We are ready to help you with your next project!

If these components fail, the louver could be unseated from the opening and cause considerable damage to the HVAC system. Water may also damage connected ductwork, resulting in loss of air pressure or other severe damage. In severe weather, water may infiltrate the duct to other system components, like control dampers or fans. Damage to these components can cause the whole HVAC system to fail, putting excess strain on other components further down the duct.

Rust damage on a duct and an unseated louverRust can build up around the opening, which can unseat the louver and cause it to fall out of the opening.

Water can also attract mold and mildew as it collects near the louver opening, which impacts indoor air quality. No one wants mold at the source of air intake. Internal filters may be able to catch mold spores as they pass through the system, but this won’t address the issue at the intake point. It can be difficult to reach and remove a louver to clean these areas. The best practice is to keep the interior dry by choosing louvers with drainable features.

Mold damage in a ventilation openingMold is a critical concern in HVAC. It's best to keep openings dry to prevent mold from growing at the ventilation source.

The Importance of Choosing the Right Louver

Don’t take an unnecessary chance to improve air efficiency. Use louvers that keep interiors dry throughout the year, such as louvers with drainable features or louvers tested for wind driven rain. Drainable louvers and severe weather louvers reject rainwater and quickly remove it from the intake point before it can pass into the duct.

Always meet your project’s requirements before considering system efficiency. Choosing the right louver is a balance between protection and performance.

For more on louvers, check out these Newsstand articles:


Do you have a question on something we haven't covered here? Or maybe you need help from industry experts? MCDLG can help. Contact us by clicking on the button below.

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  • Louvers & Dampers
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