Louvers and Openings

Louvers protect interior spaces from rain and other harmful elements while providing free area for air to flow through. They are commonly installed at air intake points, where your HVAC unit draws air into the system, but they can be placed in any opening that needs fresh air. Stationary blade louvers leave the interior open to the elements. The louver’s blades are angled to deflect incoming rain, which is fine for most scenarios. Certain applications require openings to close when they aren't in use.

Louver installed in a building — Louvers protect interior spaces from rainfall. It is important to keep ductwork dry.

You can add a control damper behind the louver to close off the duct. This can help keep the interior dry during rain, but each damper will add to project costs. These costs go beyond purchasing the damper. They need to be installed, which adds to the installation costs. These dampers will also need regular maintenance to ensure they open and close when needed. Adjustable louvers provide the benefits of a louver-damper combo, in one unit. You only need to install and maintain one unit for air control, instead of two.

Adjustable Louvers vs. Control Dampers

As the name implies, adjustable louvers are louvers with adjustable blades. Each blade will rotate along an internal axle that is tied to the louver’s linkage. If this sounds familiar, then it’s because you already know how a damper works. Adjustable louvers look identical to control dampers when compared side by side.

Although they look the same, there are key differences that set them apart.

An adjustable louver and a control damper — They may look the same, but it's important to spot the differences between adjustable louvers and control dampers.

Adjustable louvers may have a trough along the head of the frame, which captures rain at the top of the louver. Dampers won’t have this feature.
When fully open, adjustable louver blades will maintain a specific blade angle. Damper blades will maintain a straight 45-degree angle in the open position. When comparing the two, the adjustable louver will appear to be only partially open at its fully open position.
- Certain louvers and dampers can also modulate to other blade angles between fully open and fully closed. This requires adding a modulating actuator.
Adjustable louver blades will have blade features for capturing rainwater carried by the air stream, such as face troughs and catches. Damper blades will typically have a flat and featureless profile.
Adjustable louvers are installed on the outside of the building, where they are subjected to the elements. Dampers are built for indoor use, specifically in ductwork and in openings connected to ductwork.

Adjustable louvers have unique features that make them better suited for protecting intake points along the exterior of your building. Control dampers are better suited for ductwork. The full-open position of an adjustable louver maintains a specific blade angle so that they can deflect rainfall like a stationary louver. When a drainable louver is open, its drain troughs will align with the channels in the jambs. This provides an avenue for captured water to leave the louver through the sill. Adjustable louvers are designed to replace a louver-damper combo. They share many features with control dampers, but they are not the same.

Adjustable Blades

An adjustable louver blade and an adjustable louver

Several types of adjustable blades are simply stationary blades with an axle. For instance, an adjustable louver may come equipped with baffle blades like the one pictured above. The louver will perform similarly to a stationary louver with baffle blades, when fully open, but it won’t have the same performance metrics.

There are specific differences in their design that separate adjustable louvers from their stationary counterparts. Check the submittal for the adjustable louver to make sure it meets your requirements.

As we mentioned before, adjustable louver blades can also have drain features like troughs and channels. When the louver is fully open, these features align with drain channels in the louver’s jambs. Like a stationary drainable louver, the water is channeled to the adjustable louver’s sill. However, the adjustable louver will have a flat sill so that the bottom louver blade always has enough clearance to rotate.

A flat sill can make it difficult to drain water out of the louver during heavy rain. However, there are options available to combat an overflowing sill.

Options for Adjustable Louvers

Louver accessories for adjustable louvers

Adjustable louvers share many options with stationary louvers.

Drain Pans: Drain pans can help the louver drain excess water during a heavy rainstorm. The pan provides additional room for rejected water and a backplate to protect the sill from backsplash.
Blade and Jamb Seals: You can choose to add seals to the blades and jambs of the louver, to minimize air leakage when the louver is closed. These seals minimize the amount of air that passes through the louver when it is closed. Seals may come as a standard feature for some louvers.
Screens: Birds and bugs can fly between the blades when the louver is open, like a stationary louver. Add a bird or insect screen to the back of an adjustable louver to protect the interior from unwanted guests.
Finishes: Adjustable louvers can receive a paint finish to add a touch of color to the metal. These include powder paint finishes and anodizing. AWV offers no-cost color matching with all our finishes, so that you get the shade you want for your project.

They also share an important option with dampers. Actuators provide the means to control the louver’s opening and closing action. Adjustable louvers need the means to open and close on their own, which is why most louvers use electric actuators. Louvers are commonly located in areas that are difficult to reach, making it difficult to manually operate and maintain the actuator. If you’re interested in learning more, we discuss actuators and other louver accessories in this article.

A Brief Word on Combination Louvers

You may find that you like the look of a stationary louver. Those clean lines can add a touch of style to nearby surfaces. You lose that style when the louver is fully closed. To keep that look, you need a combination louver. Combination louvers contain one set of stationary blades and one set of adjustable blades. The stationary blades are situated along the face of the louver. This maintains the look of the louver even when the adjustable blades are fully closed.

An adjustable louver and a combination louver — Combination louvers keep their louvered look when fully closed.

Choose the Best Louver for the Task

Adjustable louvers are versatile. They can perform many of the same tasks as a louver and damper combo, but they may not always fit with what you need. Your louvers must meet the requirements of the project. For example, you may need wind driven rain protection and hurricane debris resistance at the opening. Most adjustable louvers are designed for standard weather protection. At AWV, we offer the LE-32C combination hurricane louver. The LE-32C is rated for AMCA 540 and AMCA 550. This louver would fit those requirements.

Understand what you need before making a final decision. Check the louver’s submittal to see if it works for your project.

An adjustable louver installed at the end of a duct — Adjustable louvers provide air control at the intake point.

AWV and Adjustable Louvers

Do you need a louver-damper combo for an upcoming project? Consider using an adjustable louver instead. At AWV, we build every louver to meet the unique needs of your building. Contact AWV today. We are ready to help you find the right louvers.

Adjustable Louvers for HVAC