Drainable vs non drainable louver 1

Drainable vs. Non Drainable Louvers: The Main Differences

There isn’t a one-size-fits-all solution when it comes to selecting the perfect louver for your application. Different scenarios require different types of louvers, each with their own unique features and benefits. This article will delve into the main differences between drainable and non-drainable louvers, two of the most commonly used types in the industry. Knowing the differences is the first step in determining the right type of louver for your application.

Understanding Louvers

Before we explore the differences between drainable and non-drainable louvers, it's essential to understand what a louver is. A louver is a ventilation product that allows air to pass through it while keeping out unwanted elements such as water, debris, and sometimes light and sound. They are widely used in various industries and buildings due to their ability to balance airflow with weather protection.

Louvers provide a mix of aesthetic and highly functional benefits. When used on the intake of an HVAC system, the velocities of the air passing through the louver can be quite high. Entrained water can be sucked into the louver, especially when coupled with wind-driven rain. Understanding this possibility helps determine whether the louver will need to be drainable or not for a given application.

Drainable vs Non-Drainable Louvers

Drainable vs. Non-Drainable Louvers

Drainable and non-drainable louvers appear quite similar upon first glance. The differences may seem subtle, but they are quite important. Let's uncover the differences:


The fundamental difference between the two types lies in their design. Drainable louvers incorporate integrated gutters within their blades and downspouts in their jambs, which allows them to capture and channel water away from the face of the louver.

As water collects on the face of a louver, the components of the louver are able to efficiently move the water away. Without these components, water is likely to fall into the airflow passing between the louver’s blades. On the other hand, non-drainable louvers have a straightforward blade design without any embedded gutters. Non-drainable louvers are more likely to draw in water in the passing airflow.

Water Penetration

Due to their design, drainable louvers are superior in reducing water penetration. The incorporated gutters and downspouts catch and channel water away before it can pass through the louver. As a result, drainable louvers are an excellent choice for areas prone to heavy rainfall or where water ingress needs to be minimized. Non-drainable louvers, while still providing a degree of water resistance, are less effective at handling large volumes of water.


When it comes to airflow, non-drainable louvers generally have the upper hand. Because of their simple, unobstructed design, they can allow more air to pass through, which makes them suitable for applications where maximizing airflow is a priority. The complex design of drainable louvers can slightly impede airflow, although this is typically a small trade-off for their enhanced water management capabilities.

Free Area

A louver’s free area represents how much of the louver’s face area is available for air to pass through. The higher the percentage of free area, the more easily air can pass through the louver. Non-drainable louvers often have higher percentages of free area than their drainable counterparts. Louvers with smaller free areas typically result in larger overall louvers being required so that airflow is not restricted and the air velocity through the louver is not excessive.


Non-drainable louvers are much simpler designs. Without the added gutters or channels for catching water, the blades are simpler to manufacture. The angle of the blades in a non-drainable louver is less important since water does not have to flow in a particular direction. The simpler design and assembly typically result in non-drainable louvers having slightly lower costs.

Damper Solutions from United Enertech

United Enertech understands that every project is unique and needs a tailored solution. Their wide range of drainable and non-drainable louvers are designed with this in mind.

Drainable louvers, such as the FL-D-2 and the FL-D-4, are engineered with deep drainable blades and downspouts, perfect for applications where water penetration is a significant concern. These models have been tested to AMCA standards to ensure high performance and reliability.

Damper Solutions from United Enertech

On the other hand, if maximizing airflow is your priority, their non-drainable louvers like the EL-4 and the SFL-4 series offer excellent air passage with a degree of weather protection. These louvers, too, are tested to AMCA standards and are available in a variety of blade angles and depths.

Choosing the Right Louver

Choosing between drainable and non-drainable louvers depends largely on your application and specific needs. While drainable louvers provide superior water management, non-drainable louvers are often the go-to choice for maximizing airflow and are often sufficient for the application.

At United Enertech, they are committed to helping you make the best choice for your project. The United Enertech team of louver experts is always ready to guide you through their diverse range of louvers, to help ensure that you select the perfect solution for your unique application.

For more information about their drainable and non-drainable louvers, or any other air control solutions, don't hesitate to contact United Enertech today! Bring your project to life with United Enertech's proven performance and reliability.

Contact United Enertech today.