A Guide to Get Started With HVAC Dampers

Air quality in O'Fallon, MO
Updated August 23, 2024

An HVAC damper is a device that regulates the airflow in and out of your home. It’s used in heating, cooling, and ventilation systems. It’s important to understand how they work and what they’re used for to maintain your system and keep it running efficiently.

A damper is usually placed near the end of each duct run and has three positions: closed, half-open, and fully open. The closed position blocks airflow completely, while the half-open allows only partial airflow. The fully open position allows maximum airflow out of the ductwork.

Contact Us for AC Service Today!

When Can You Open and Close the HVAC Damper?

The short answer is that you can open and close anytime the temperature in your home or building needs to be altered, according to Hoff Heating & AC in O’Fallon, MO, where the temperature fluctuates dramatically.

The longer answer is that you should open or close your HVAC damper when the outdoor air temperature is higher or lower than the indoor air. Opening the damper allows more fresh air, lowering its temperature as it passes through the building’s ducts. Closing down the damper restricts airflow outside, forcing your heating or cooling system to work harder.

If you have a forced-air furnace or central AC unit, closing down your ducts can improve furnace efficiency by allowing it to run at lower temperatures while providing adequate heat for the heated space. For example, if you live in an area where outside temperatures are consistently below 40 degrees F, opening up your air ducts might not make sense because it would lower indoor temperatures too much when outside temperatures are cold. In this case, closing down your ducts helps conserve energy by reducing how much fuel is required for heating.

Functions of Dampers

Most HVAC systems have dampers installed. There are some exceptions to this, but most of the time, you will find them in your system. If you do not have one installed, then it is time to call an HVAC contractor and have one put in.

HVAC duct dampers are primarily used to regulate airflow through the HVAC system. However, they can also be used as part of an exhaust or supply system. In this article, we’ll discuss the basic functions of dampers and how they work with other components in the HVAC system.

Airflow Regulation

Airflow regulation is one of the most basic functions of an HVAC damper, but it’s also essential for the proper functioning of any forced air heating or cooling system. Dampers control how much air can enter or leave your home through the ductwork by regulating the opening size and determining how much pressure builds up behind it when closed. This pressure can be used by other components in your HVAC system, such as blowers and fans, which require pressure to operate properly.

Types of Dampers

There are two main types of dampers according to how they are controlled: motorized and manual. Both work by closing off the flow of air, but they do so differently:

Motorized Dampers

Motorized dampers are designed to automatically open and close based on the demand for heating or cooling in a room. They work by sensing when heat or cold is needed and then opening or closing accordingly.

Manual Dampers

A manual damper is installed in your ductwork grille to control airflow. You open or close the damper when you want to control airflow. Manual dampers are typically used for smaller home heating systems, such as furnaces and heat pumps.

They are used in a forced-air system to control airflow through registers and grills. It is opened and closed manually by turning a handle or knob. These dampers are often used in combination with registers so that you can direct airflow.

Other types of dampers include:

Butterfly Flat Dish Damper

A flat disc that has a circular opening at one end and a flap at the other end. When the flap is open, air flows through the opening. As you move away from this position, the flap closes off the opening until it reaches its fully closed position, where there is no longer any airflow through the unit.

Blade Damper

A flat plate that rotates on a central axis to close off different-sized holes in a vent or ductwork system. Blade dampers are commonly found on bathroom exhaust systems and kitchen range hoods. They are also used in furnace vents and ductwork systems.

Guillotine Damper

This type of damper uses a series of blades that swing outwards when activated by an actuator inside your system. In this situation, there is no need for an actuator since gravity will cause these blades to swing outward once they have been opened up by someone working on your system.

Louvered Dampers

A louvered damper consists of multiple blades that move in unison to control airflow through the ductwork. They are also known as a “Venetian” style louvered damper because they look like the louvers found on Venetian blinds. While these are not commonly used in residential HVAC systems, they may be found in commercial applications such as industrial ventilation systems or large-scale power plants.

Inlet Vane Dampers

These are usually found on clothes dryers. They allow hot air to escape from the dryer while preventing cold air from entering. It helps maintain a consistent temperature inside the dryer so that your clothes will dry faster and with less energy consumption than they would if they were dried outside due to wind or other factors.

Common Problems Associated With HVAC Dampers

HVAC dampers can develop problems for several reasons. Listed are some of the most common problems:

Damper seals leak

Damper seals are one piece of material installed around the perimeter of an opening and then secured to the frame or wall by screws or nails. Over time, these seals can become worn out or damaged, allowing air to leak through them when they should be closed.

Damper motors break

The motor that operates your damper may be faulty or broken, causing it not to open or close when you want it to. In addition, it can lead to overheating in your home because heat cannot escape from your ductwork properly.

Damper motors fail prematurely

Sometimes, it’s not just one part of your damper that fails, but rather multiple parts fail at once (such as both motors).

It may not be easy to close or open if your damper sticks. This can cause problems because it can prevent airflow from moving through the ductwork. If this happens too long, the air conditioning unit will overheat and need repair work done immediately.

Hoff Heating & AC has been serving the O’Fallon, MO community for many years. We offer a range of services, such as repairs and installations. Our technicians are fully trained to handle any situation and can walk you through the process every step.
We also offer indoor air quality services to ensure your home or office is safe from harmful contaminants. It can include everything from duct cleaning to mold removal. If there is anything we can do for you, please do not hesitate to contact us today!