Louvers and HVAC

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If you’ve ever been inside a stagnant room, you can understand the importance of adequate airflow. Air louvers are critical elements of design for heating, ventilation, and air conditioning. Let’s explore how these architectural elements impact comfort, the different types of louvers, and how these elements ensure air quality and safety inside buildings.

What is a Louver? 

A louver, sometimes spelled louvre, is a design element of blinds or shutters with horizontal angled slats used by architects, designers, and engineers. There are multiple types of louvers, and each has its purpose and functionality. Some are purely decorative, while others, such as air louvers and HVAC louvers, regulate airflow in different conditions or situations.

You have probably seen louvers in closet doors and window blinds. These styles are more on the decorative side, although they can be used to provide airflow between rooms or from outdoors to indoors.

Since louver slats can be stationary or adjustable, there is added versatility in how they are used. Movable louvers are popular for wood blinds, allowing light to filter into a room while preventing visibility.

3 Types of Louvers

  1. Decorative louver
  2. Stationary louver
  3. Adjustable louver

What is a Decorative Louver? 

In architecture and design, louvers can hide unattractive elements of a building that we don’t want people to see. For example, designers can place a louver over a panel door to allow easy access for maintenance while keeping the design visually appealing. These louvers come in all shapes and sizes and can be custom-made to fit any opening.

Stationary Louver Purposes

Decorative louvers are typically stationary because the primary purpose is to provide a visual element rather than primarily functioning as an air louver. Stationary louvers are the most common and are usually constructed from rigid plastic or metal with no moving parts. Stationary louvers are popular for sunscreens, window and door shades, and as access door covers that are purely decorative. Since stationary louvers don’t have moving parts, there are different considerations to make when using them, including spacing, sizing, and the number of blades.

Adjustable Louvers

An adjustable louver has movable parts that allow you to control the positioning of the blades. Movable blades allow adjustable louvers to be used in different settings and to give you more control over the airflow or temperature level.

Louvers in HVAC Design

Louvers can’t control the temperature and air quality of an entire building without help from other HVAC products. HVAC louvers can circulate hot or stale air from within a building to the outside while filling the inside space with cool, fresh air. HVAC louvers are also helpful in reducing the risk of mold by preventing moisture from accumulating inside a building.

What are Industrial Louvers? 

In addition to stationary or adjustable louvers, different louver applications impact the material and durability. For example, industrial louvers are made from wood or metal and are made to withstand extreme wind, rain, and snow. You’ll typically find industrial louvers in factories or warehouses and in some office buildings.

Industrial louvers can help provide higher air quality inside manufacturing facilities. Since poor air quality inside a building can contribute to or even cause cancer, infections, and chronic conditions, louvers help remove pollution such as:

Exhaust Louver Purposes

If you have a clothes dryer, you should have a vent that transports the hot air and extra lint outside your home. The opening of this vent is typically covered with an exhaust louver. This cover prevents animals such as birds from making a nest in your ductwork and stops rain and other moisture from being blown into the duct while allowing hot air to escape.

Exhaust louvers are also seen frequently in home and commercial building foundations. Louvers help regulate the amount of air in the space while preventing moisture from becoming trapped.

Louver System Questions

There are a lot of questions you should ask before selecting a type of louver system for your building. Understanding the needs of your louver, as well as the environmental conditions of the area you’re building in, will help ensure that you make the proper selection and that the louver meets your needs. 

Here are three things you should keep in mind when selecting a louver: 

  • Water penetration
  • Louver-free area
  • Pressure loss

What is Louver Water Penetration? 

If you live in a particularly wet area, knowing your louvers’ water penetration resistance is critical to keeping your space dry. According to the Air Movement and Control Association International (AMCA), water penetration resistance refers to the amount of water that can pass through a louver under specific conditions. This amount is calculated by dividing the weight of the water that passes through the louver by the amount of free area at a specific free area velocity and tells us at what point the louver will leak when exposed to water.

What is Louver-Free Area? 

Every louver has a louver-free area calculation. To calculate the louver water penetration, you need to know the louver-free area. This amount is found by dividing the total open area of the louver by the area of the wall opening. Higher percentage free areas are better because it allows for more airflow by using a smaller footprint. Typical free areas range from 35-60%.

Pressure Loss in Air Louvers

Pressure loss in louvers, also known as resistance to airflow, is the amount of wind resistance created by the blades and other design characteristics. Although there will always be some level of airflow resistance, the goal is to minimize the resistance as much as possible because too much resistance can damage the louver, cause higher energy use, and increase pressure. The amount of wind resistance is calculated by measuring the free area velocity and pressure differential of the louver.

How to Choose the Right HVAC Louver? 

Understanding how louvers work and what conditions your louver will need to operate in is the first step to ensuring that you are happy with the outcome – and that your building is protected. Unless you have extensive experience in HVAC design, speak with an expert who knows the regulations, environmental conditions, and other specifications of different louvers to see which style will work best for your needs.

Louvers play an important role in fire prevention and safety. When paired with fire dampers, brick vents, and other essentials, it’s easy to keep your space safe and secure.