MCDLG Newsstand

Options for Louvers

In this article, we discuss the accessories and optional features that you can add to a louver. From aesthetic changes to functional enhancements, you have options for your louvers.

Your choice begins with finding the best louver for the task at hand, but it doesn’t end there. Consider the available options and accessory parts, too. Louver options can be purely aesthetic, or they can add additional functions to your louver. It is important to understand what these options add to your louver and how they may affect its performance. We begin with aesthetic options and accessories.

Finishes – Mill, Powder Paint Coats, and Anodizing

Aesthetics are important to louver design. Your louvers will be a part of your building’s exterior. When it comes to aesthetics, finishes are the first option that comes to mind. You can choose to keep your louvers with the standard mill finish, which is bare metal and nothing else, but they might not work with the rest of your building. Powder paint and anodized finishes add color to dull metal.

Architectural powder coatings are applied through a multi-stage process. First, the louver is washed multiple times to remove any impurities from its surfaces. Then, the louver receives a base coat after cleaning, and before the powder coating is applied. The powder coat is applied to the louver through a process called Electrostatic Spray-assisted Vapor Deposition (ESAVD). During ESAVD, static-charged powder paint is applied to the grounded louver with a spray gun. The paint is attracted to the louver as it leaves the nozzle, ensuring a good coat with minimal wasted paint.

With the powder coat applied, the louver is placed in an industrial oven to bake. The baking process disperses the powder coat evenly across the louver and cures the finish. The complete powder paint process ensures a long-lasting color finish, resistant to fading, chalking, and marring. Powder paint finishes are expected to last for 5 years for the basic powder coat, and up to 20 years for the high-end powder paints. You may also choose to add an extra clear coat to the powder coat finish, for an extra layer of protection. This clear coat can extend the life of the finish to 30 years. Manufacturers will offer warranties on their finishes.

A finished louver in the middle of the drying process

Pictured: a louver in the middle of the drying process. Once fully dry, the louver's finish will be resilient to fading, chalking, and marring.

You can also apply an anodized finish to your aluminum louver. Anodizing adds a protective coat to the louver to prevent rusting and other signs of wear. To receive an anodized coating, a louver is immersed into an acid electrolyte bath and subjected to an electric current. A cathode is placed into the bath, while the louver becomes an anode. To summarize the process, oxygen ions are released from the electrolytes in the bath and combine with the aluminum atoms on the surface of the louver. In a sense, the anodizing process is a fast and controlled form of natural oxidation. The result is a permanent protective layer that helps the louver withstand the elements. Manufacturers will apply a clear coat to give the louver an added shine. You may choose to add special dyes to the clear coating to add color to the finish. Options for dye are limited to a few colors and the resulting color may vary depending on the metal alloy used to build the louver. Anodizing is available for aluminum louvers only because the process works best with aluminum’s porous surface. Steel louvers are not guaranteed to receive the benefits of anodizing.

Powder paints are the most versatile option of the three finishes at a mid-range cost between mill finish and anodizing. Mill finish, or no finish, will be the cheapest option, but will leave your louvers unprotected from the elements. Mill finish louvers are more prone to corrosion. You will have more colors to choose from with a powder coat, plus the option to color match to the exact color you are looking for. On top of that, you can add an extra clear coat to further protect the finish. Consider a nice powder paint for your louvers or go for the metallic anodized finish. Turn your louvers into works of art and protect them from the elements!

You can choose from the standard mill finish, powder paint finishes, and anodized finishes.

From left to right: Standard mill finish, powder coat finish, and anodized finish with bronze.

Custom Shapes

There is more to louver aesthetics than the finish. You can design louvers in other shapes, beyond the usual square and rectangular frame. These are often referred to as custom shapes. Manufacturers can typically build louvers as a circle, a semi-circle, an oval, or a triangle. Check the manufacturer’s literature for a complete list of custom shapes. You can often place multiple louvers within the same opening to achieve a new shape, like something resembling an arch way. Custom shapes are only limited to your creative and artistic flair.

A circular louver

Custom shapes turn square louvers into works of art! Choose from circular, triangular, oval, or any shape that fits your project.

Exercise caution when ordering a custom shape. Changing the shape of the louver will change the way it performs in the opening. AMCA tests are only applied to square and rectangular louvers. Therefore, the data collected from each test assumes the louver is a traditional square or rectangle. Louvers rated by AMCA may not keep their ratings when designed as a custom shape.

Frames – Flange Frames, Sill Extensions, and Subframes

Louvers are typically mounted into ventilation openings on the side of your building. From there, they provide inlets and outlets for your HVAC system while protecting the interior from unwanted elements like rainfall. The frame of the louver can sit flush with the wall, recessed within the opening, or protruding from the opening like a telescope. Whichever way you install it, there are optional parts available for the louver’s frame.

Flanges are metal sheets installed along the perimeter of the louver, either on the face side or rear side. Flanges cover the seams created between the louver’s body and the edges of the opening. A flange frame is any louver frame with flanges installed. You can add flanges to the head, sill, jambs, or on all sides of the louver. Add a finish to the flanges to match the louver or pick a contrasting color to make the louver stand out. Flange frames are an aesthetic accessory that creates a seamless look between the louver and the wall receiving it. Learn more about flange frames with a short read from the MCDLG Condenser: Flange Frames and Seamless Design. Consider adding flanges to your louver’s frame.

Flanges can be added to any side of a louver to cover the seam of the opening.Flange frames extend past the louver face to cover the seams created by the opening. Flanges can be added to sills, heads, or jambs.

When recessed, the louver may have trouble draining water from its sill. This can cause excess water to collect inside the opening. Sill extensions are added to the louver’s sill to fix this problem. The extension piece is installed on the louver’s sill and extends over the edge of the opening. This provides a better path for water to follow as it drains from the sill. This feature also protects building features beneath the louver by directing water away from the building’s surface. The sill extension can be ordered to match the color of your louver, or in a different color to add a nice contrast. Consider adding a sill extension when installing a recessed louver.

Subframes are auxiliary frames that surround the base frame of the louver. Subframes are mounted into the opening first, so that the louver will be installed inside the subframe. With the right equipment, you can do several things with this setup. You can add a latch and hinges between frame and subframe, to turn the louver into an easy-open hatch. Additional hardware can make the louver removable from the subframe or restrain the louver in place. Subframes can receive a finish to match or contrast its louver. If you want to add new features to your louver, then consider adding a subframe. When ordering, be sure the subframe fits in the intended opening and that the louver will fit within the subframe. 

Need to brush up on the parts of a louver? Read our Condenser article: Anatomy of a Louver.


Aesthetics are important, but functional options make louvers more versatile. These options can provide new features or enhance the louver’s current capabilities.

Drain Pans

Drain pans are metal collection pans with an open face. The louver will sit in on top of the drain pan, such that the louver is facing the open side of the pan. The back side of the pan will cover the sill area of the louver, so that excess drainage does not accidentally drain back through the louver. These pans are designed to capture and expel any water that collects around the sill.

Drain pans curve downward, like a ramp, towards its open face. This design allows the water to fall naturally out of the face. Drain pans are an excellent option for louvers designed to resist rainfall. You can also apply a finish to the drain pan, to match or contrast with the louver. In some instances, like hurricane and wind driven rain louvers, the drain pan will be a standard feature. If you are expecting heavy rainfall, then add a drain pan to your louver.

Screens – Bird Screens and Insect Screens

Louvers prevent unwanted elements from passing into the ductwork beyond. Sometimes unwanted guests, like birds or insects, can pass through the space between blades. From there, they can cause all kinds of trouble. Add a screen to your louver and prevent these unwanted guests from entering your HVAC system. Louver screens are typically installed on the back side of the louver.

There are two types of louver screen: bird screens and insect screens. Bird screens have large holes, resembling a chain link fence, to block birds from entering through the louver. Insect screens will have tiny holes, like a mesh, to prevent insects from passing into your ductwork. Here are a few differences to consider when choosing one screen over the other:

  • Bird screens have larger holes, which would not block small insects from passing through the louver. Insect screens will block anything trying to get through.
  • Bird screens have a minor effect on the louver’s air performance. Air can pass through the screen with relatively little resistance. Insect screens will have a significant impact.
  • Bird screens can receive a finish to match or contrast the louver. Painting an insect screen is not recommended.

Consider these differences before selecting a screen. If you know that unwanted guests will be an issue with your louvers, install a screen and keep them out of your HVAC system!

Insect and bird screens keep these critters from entering through your louver.

This image demonstrates a bird screen installed over an insect screen. Yes, you can have both! This configuration can provide the best level of protection at a cost of the louver's air performance.

Blank-Off Panels

In some instances, you may not want air to pass through part of the louver. It may seem hard to believe, but there are also times when you will want a louver to block air flow. Designers and architects can use louvers to compliment other features along the building’s envelope.

For example, you could mount a louver into an opening with no ductwork behind it. Air flow would wreak havoc on this louver and could potentially unseat it from the opening. If the louver serves a functional purpose, then an adjustable louver is the best option; they can open and close their blades. For purely aesthetic louvers, you can use a blank-off panel to close off part of the louver or block off the entire louver.

A full blank-off panel attached to the back of alouver

Blank-off panels block airflow from passing through the louver. This can be important if you need the louver for aesthetic purposes only.

Blank-off panels are solid sheets of metal fastened to the back side of the louver. Once in place, the panel will block air from passing through the louver. With blank-off panels, you can keep the look of a louvered surface without worrying about air flow. Blank-off panels can also be designed to cover part of the louver, instead of the entire back. Panels can also receive a custom finish to match the louver. Consider blank-off panels for louvers that serve a more artistic purpose.

Actuators – For Adjustable Louvers

Adjustable louvers have blades that can rotate to open or close, like a control damper. These louvers can open periodically, to allow air in only when it is necessary, and close to keep out unwanted elements like snow and rainfall. Adjustable louvers can be equipped with an actuator to facilitate the louver’s opening and closing actions.

For a full breakdown on actuators, read our Newsstand article: Actuators - Making Adjustments

To summarize, actuators can be one of three distinct types. Manual actuators are operated by hand, while electric actuators use power and pneumatic actuators utilize air pressure. Manual actuators are not typically used in adjustable louvers since louvers are installed on the sides of a building. The actuator would be in a hard-to-reach place, making it difficult for the operator to adjust the blades.

Electric actuators are considered the best choice for louvers, since they can operate the louver remotely, can rotate blades automatically, and require less maintenance. Pneumatic actuators can also automate blade rotation but require a centralized air compression system. Pneumatic actuators must also be replaced on a routine basis. Adjustable louvers work best when they can open and close as needed. Automate your adjustable louvers with actuators.

You have options for louvers: custom shapes, finishes, add-on parts; for form and function!

Louver Options

As you can see, there are plenty of options for louvers; from aesthetic enhancements to functional upgrades, to automating blade rotation. Turn your louvers into versatile air control devices with these optional accessories.

Which options have you added to your louvers? Are there any must-have options for your projects? Share your thoughts on louver accessories in the Comments section. We want to hear from you!

MCDLG & Continuing Education

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

Our louver course, Louvers for Style and Aesthetics, goes over the basic stats, terms, and principles involved in choosing louvers for any application. You will also learn to use louvers to enhance the aesthetic of your building.

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!

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. 

Click here to contact MCDLG


Get printed materials from MCDLG with our PDQ Portal

Sign up to our PDQ Portal for printed materials from MCDLG brands.

Mestek Commercial Damper and Louver Group

MCDLG is a collective of top-tier HVAC brands.
  • Arrow United Industries
  • Air Balance
  • Cesco Products
  • Louvers & Dampers
  • Airline Louvers

We build every louver and damper from the ground up to meet your specifications. Our team works to ensure that you get the best solutions for your project's requirements.

Want to know more? Contact us online through the MCDLG Contact page. We are ready to help!

Click here to contact MCDLG 

Subscribe to Email Updates