What is a Range Hood Damper? And How Does It Work?

September 04, 2023 8 min read

The range hood is pivotal in maintaining a clean and healthy kitchen environment. However, many may not realize that the range hood consists of several components, including the range hood damper. The range hood damper plays a crucial role in ensuring that the hood functions appropriately by regulating the airflow and preventing unwanted particles and odors from entering your kitchen.

In this article, we'll take a closer look at what a range hood damper is, how it works, the different types available, and how to choose the right one for your needs. So, whether you're looking to replace an old damper or want to learn more about this vital kitchen appliance, keep reading to find out everything you need about range hood dampers.

What is a Range Hood Damper?

A range hood damper also called a draft regulator, is a small device installed in the ductwork of a kitchen ventilation system to regulate airflow. It controls the direction of air movement, allowing air to flow through the range hood and preventing it from flowing back into the kitchen. This helps to remove cooking fumes, smoke, and moisture and maintain healthy air quality by preventing air, dust particles, and debris from entering the kitchen.

How Range Hood Damper Work

Range hood dampers control the direction of air movement, allowing air to flow out of the kitchen through the range hood and preventing it from flowing back into the kitchen when the range hood is not in use. In conjunction with a range hood fan, the damper helps to remove cooking fumes, smoke, and moisture from the kitchen.

The range hood damper can open and close based on the fan's speed because it is designed with springs and pivots sensitive to air pressure changes. When the fan is turned on, the increased air pressure causes the damper to open. When the fan is turned off, the decreased air pressure causes the damper to close.

Here is a step-by-step breakdown of how they work together:

  1. The range hood fan is turned on, creating negative pressure in the kitchen that draws in air and cooking fumes through the range hood.
  2. As the air and cooking fumes are drawn into the range hood, they pass through the range hood filter, which removes grease and other particles.
  3. The air and fumes then pass through the range hood damper, which is located in the ductwork of the kitchen ventilation system. The damper is designed to open and close based on the fan's speed.
  4. When the fan is turned off, the damper remains closed, preventing air from flowing back into the kitchen from the outside. This helps to maintain the healthy air quality in the kitchen.
  5. The damper opens when the fan is turned on, allowing air to flow out of the kitchen and through the range hood.
  6. As the air and fumes flow through the ductwork, they are expelled outside through the exhaust vent.

It is important to note that not all range hood dampers are the same. Different types of dampers are available on the market, including gravity, butterfly, and motorized dampers. Every kind of damper has pros and cons, and the type best for a particular kitchen will depend on several factors.

Types of Range Hood Dampers

The main types of range hood dampers are:

1.   Gravity Dampers

A gravity damper is a type of range hood damper that operates using gravity to open and close. It consists of a simple flap attached to a hinge and is designed to swing freely in one direction, opening up to allow air to pass through when the range hood fan is turned on and closing shut when the fan is turned off.

Gravity dampers are typically made of lightweight materials such as aluminum or galvanized steel and are designed to be installed in a horizontal duct run. They are easy to install and require minimal maintenance, making them a cost-effective option for homeowners.

However, gravity dampers have limitations in terms of air control. They are less effective in preventing backdrafts and can sometimes be noisy when the flap swings open and shut. Additionally, their construction may be less durable than other dampers and unsuitable for commercial kitchens or high-demand settings.

2.   Butterfly Dampers

A butterfly damper is a range hood damper that uses a set of blades resembling butterfly wings to regulate airflow. It is typically installed within the ductwork and can be manual or motorized.

When the range hood fan is turned on, the butterfly damper opens to allow air to flow out of the kitchen. When the fan is turned off, the damper blades close, preventing air from flowing back into the kitchen. The blades can be adjusted to control the air flowing through the ductwork.

Butterfly dampers are typically made of aluminum or galvanized steel and are popular for those seeking greater control over their kitchen ventilation system. They are well-suited for applications requiring precise airflow control, such as in commercial kitchens or for individuals with specific ventilation needs. Motorized versions can be controlled with a switch or remote control.

3.   Backdraft Dampers

A backdraft damper is a range hood damper designed to prevent the backflow of cold air from the outside to the inside of a kitchen. This type of damper is typically installed at the point where the range hood ductwork exits the building to the outdoors.

Backdraft dampers use a one-way flap that allows air to flow out of the kitchen through the range hood ductwork but prevents air from flowing back into the kitchen from the outside. The flap is spring-loaded and held closed by the air pressure inside the ductwork. When the range hood fan is turned on, the airflow pressure opens the flap, allowing air to escape through the ductwork to the outside. When the fan is turned off, the flap closes again, preventing outside air from entering the kitchen.

The main advantage of a range hood backdraft damper is its ability to prevent outdoor pollutants such as smoke, dust, and allergens from entering the kitchen. They also protect against wind-induced downdrafts, which can cause smoke and fumes to backflow into the kitchen. Backdraft dampers are commonly used in kitchen ventilation systems in areas prone to high winds or close to sources of outdoor pollutants, such as highways or industrial areas.

  1. Control Dampers

A control damper is a range hood damper used to regulate the volume of air flowing through a kitchen ventilation system. It is a more advanced version of the gravity and butterfly damper and is commonly found in larger commercial kitchen ventilation systems.

Control dampers use a set of blades to adjust the amount of air that passes through the ductwork. The blades are connected to a motor or actuator that can open or close them, allowing the user to adjust the airflow as needed. Control dampers can be manually or automatically operated, and some models can be linked to a building automation system for remote control.

They have precise air control, which can help maintain consistent indoor air quality, and the ability to adjust airflow to meet changing kitchen ventilation needs. They are also easy to install and maintain. However, they are more expensive than gravity dampers and butterfly dampers.

Control dampers are most commonly used in large commercial kitchen ventilation systems, such as in restaurants and hotels. They are often installed where the range hood connects with the central ductwork and is used with a wall or roof cap and other types of dampers to ensure optimal airflow and air quality in the kitchen.

4.   Balancing dampers

Balancing dampers are commonly used in large kitchen ventilation systems with multiple exhaust hoods and ductwork. They are often installed at the branch points where the ductwork divides into smaller sections. Balancing dampers can be manually adjusted to control the airflow between the different areas of the ductwork and balance the system's pressure. They can also be automated using motorized actuators that adjust the damper's position based on sensor signals that monitor the airflow and pressure. Balancing dampers are designed to prevent excessive pressure in any one section of the duct system, which can cause air leaks, reduce efficiency, and increase energy consumption.

5.   Shut off dampers

Shut-off dampers are a type of range hood damper that can completely shut off the airflow in a kitchen ventilation system. These dampers are usually used in emergencies or when maintenance needs to be performed on the system.

Shut-off dampers use a rotated blade or disc to block or allow airflow. They are often motorized and controlled by a switch or automated system.

The main advantage of shut-off dampers is their ability to quickly and effectively stop airflow in a ventilation system, which can be important in a fire or other emergency. However, they can also be expensive to install and maintain and may not be necessary for all kitchen ventilation systems.

Shut-off dampers are most commonly used in commercial kitchen ventilation systems where fire suppression systems are required by code. They may also be used in residential systems for added safety measures.

How To Choose the Right Range Hood Damper

A range hood damper is an essential component of a kitchen ventilation system, which helps to exhaust smoke, fumes, and moisture from the cooking area. When choosing the suitable range hood damper, several factors should be considered, including the type of vent hood, the ductwork size, the air volume required, and the local building codes.

Firstly, it is essential to consider the type of range hood. There are two main types of range hoods: ducted and ductless. Ducted range hoods require an external exhaust system to vent smoke and fumes, while ductless range hoods recirculate the air through a filter. If you have a ducted range hood, you will need a damper that fits the ductwork and can withstand the air volume generated by the fan.

Secondly, the size of the ductwork is also a critical factor. The damper should match the ductwork size to ensure proper airflow and ventilation. A damper that is too small for the ductwork can cause back pressure, reducing the range hood's performance and damaging the fan motor. On the other hand, a damper that is too large for the ductwork can lead to air leaks, which can reduce the efficiency of the ventilation system.

Thirdly, it is important to consider the air volume required for the range hood. The damper should be able to handle the maximum air volume generated by the fan. The air volume is measured in cubic feet per minute (CFM), and the damper should be rated to match or exceed the CFM of the range hood fans.

Finally, local building codes should be considered when choosing a range hood damper. Some building codes require specific types of dampers, such as fire-rated dampers or dampers with backdraft prevention. It is important to consult local building codes and regulations to ensure compliance with safety standards.

When selecting a range hood damper, choosing a model compatible with the range hood and the ventilation system is essential. It is recommended to purchase a damper from the same manufacturer as the range hood to ensure compatibility. Proper installation and maintenance are also crucial for the damper to function correctly. The damper should be installed in a location that allows easy access for cleaning and maintenance. Regular cleaning and inspection of the damper are necessary to prevent blockages and ensure proper airflow.

A makeup air kit with dampers can be designed to provide fresh air to a building or space experiencing negative air pressure while also allowing for airflow control. The kit typically includes a fan, ductwork, intake vents, and dampers that can be adjusted to regulate the amount of airflow entering the space. The dampers are usually installed at the intake vents and can be adjusted manually or automatically to control the flow of air entering the building. This allows for greater flexibility in managing the ventilation needs of the space and can help eliminate poor indoor air quality while reducing energy costs by preventing over-ventilation.

Final Thoughts

A range hood damper is a very nifty device that offers an inexpensive solution to a problematic downside of external venting. Most dampers work with the thermostat to help maintain optimum airflow in the kitchen area. You can effectively vent your kitchen without worrying about backdraft, polluted air, or pathogens finding their way back in.