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The Condenser - Louver Screens and Uninvited Guests

Are critters making home in your HVAC system? They may be coming through the louvers. Learn how to stop uninvited guests with louver screens!

Louvers are made to allow air flow into a building and keep everything else at bay. All louvers have free area between their blades for air to pass through into the duct work. And larger louvers will have more free area.

Screens protect louvers from uninvited guests, including insects and birds

More free area means there is more space for air to pass between louver blades, which means lower pressure drop and better air performance for the louver. But it can also mean more space for unwanted elements to get through the louver.

With enough free area, birds and insects can infiltrate the louver's free area and enter your duct work. These unwelcome guests can set up homes in your duct and wreak havoc on your HVAC system. 

So, how do you close up a louver? You need that free area to let air through, right? You can choose to install a louver screen on the back side of your louver. 

Louver Screens

Louver screens are installed on the interior side of a louver, to keep critters out while minimizing the impact on your louver’s air performance. 

Louver screens are made from aluminum or steel wire, twisted into links that make up a mesh like a chain link fence. This mesh can be installed in its own frame, with quick release clips or vandal proof fasteners, for easy removal and re-mounting. Or, fix it directly to the back of the louver with screws.

Screens are typically installed on the back of the louver

A screen will provide protection from uninvited guests at the cost of air performance. This cost depends on the type of screen you use.

The Common Visitors - Birds and Insects

Birds and insects are common visitors for louvers, especially in elevated places. Installing a louver screen is the best way to keep them out.

There are two types of louver screens: bird screens and insect screens. Insect screens have smaller links than bird screens, leaving no room for smaller critter to get through.

Pictured is a bird screen installed over an insect screen, for dual layer protection

Bird screens have large links, allowing air to pass through unhindered. These screens have a minor affect on the louver's air performance: the large links have little impact on the louver's free area and allow air to pass through with ease. However, smaller critters can still make it through the larger links.

Insect screens are more effective at keeping everything out, but they will have a greater impact on the louver’s air performance. The smaller links of the insect screen mean less space for air to pass through the louver. This means the louver will have less free area between the blades and a greater pressure drop as air tries to pass through the screen. Depending on where the louver is installed, you may want to take the hit to air performance to keep smaller critters out.

Closing the Door on Uninvited Guests

Consider louver screens if your louver will be frequented by birds, flying insects, or other critters. These can be larger louvers, louvers in high places, or louvers in humid areas with lots of bugs. A bird screen will keep larger critters out while maintaining the louver's air performance. Insect screens will affect your louver's air capabilities, but their smaller holes with keep insects out of your ductwork.

Don't let unwelcome guests into your HVAC system. Close the door and keep your duct work clear. Consider installing a louver screen on your louvers.Bird screens can be installed on severe weather louvers


Have you added screens to your louvers? Which type have you seen more often: bird screens or insect screens?  Share your experience with louver screens in the Comments section below. We want to hear from you!


Continuing Education - Transparent Office (Square)MCDLG & Continuing Education

MCDLG offers free self-paced courses online through AEC Daily. 

Our louver course, An Introduction to Louvers, goes over all of the basic stats, terms, and principles involved in choosing louvers for any application. Visit AEC Daily to browse our online courses

This course provides continuing education credits for a variety of institutions, including AIA's LIUs. Learn the basics of louvers and earn credit, at your own pace. Visit the MCDLG course page on today!

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