How to Adjust Air Duct Damper of HVAC Unit?

HVAC units have become vital parts of our home and commercial areas. Without HVAC units, some sectors wouldn’t be able to function efficiently. However, running them at full capacity across every room costs you a lot. Not just the energy bills, but other costs like maintenance and repair will also be huge. To avoid that, we create zones using air duct dampers.

These dampers help you control airflow in different rooms. Moreover, they help in regulating temperature and humidity as well. This function significantly helps you save costs on energy and maintenance bills. In this blog, we will discuss in brief the dampers and how to fine-tune them to suit your requirements.

What is Air Duct Dampers?

They are the hinged devices mounted in the ducts of the HVAC unit. The purpose of the dampers is to control the airflow in your home or office. They get installed in the ducts at the points where you control the airflow, either for heating or cooling. They have a door or a plate, which opens and closes in order to regulate the flow of air.

Without them, you will have no way of achieving your preferred settings in a specific area. Some confuse them with vents installed in the walls. However, HVAC dampers are much larger. They are inside the duct, controlling the entirety of the airflow.

Types of  Dampers in HVAC

Depending on the purpose of the air duct dampers, they vary in size and shape. Let’s take a look at some of main types of dampers in HVAC systems.

  1. Manual Damper: 

Manual dampers are pretty old-fashioned. They have a valve outside the duct that you can use to control the airflow by moving it up or down. They don’t require much maintenance. However, you cannot achieve precise airflow values using this type of damper.

  1. Automatic Damper:

Automatic dampers use electronically controlled motors to control the opening and closing of the duct. These are much more precise than manual dampers. They also offer self-regulation where you can set a constant value of the airflow and the dampers move to always provide the right airflow.

There are further classifications of dampers too. Most dampers come under one of the above two categories. But, you can see that both of them need adjustments to suit your requirements. You have to be careful with fine-tuning your dampers. Tuning them properly means better energy usage and efficiency.

Do all HVAC Systems have dampers?

If you do not have an HVAC system that supplies different airflow and setting to different rooms, having air duct dampers is unlikely.

How to Adjust Air Duct Dampers?

You can follow the below steps to adjust your dampers the right way. If you are quite unsure about it, you can contact experts to handle your equipment.

Step 1: Turn on the system

The first step is to turn on the HVAC system. Ensure that your fan runs at optimal capacity and that your air duct dampers align with the direction of the duct. This ensures that the air is flowing without any disturbance.

Step 2: Maintain the same conditions in every room

Now, open all the vents in every room to let the air flow evenly across every room. This allows you to check if any of the duct valves are faulty. Also, you can determine which duct is for which rooms within the facility/home.

Step 3: Adjust the dampers: 

Using the levers, start by making minor adjustments. Remember that the duct is completely in an open position now. After adjusting your dampers, constantly look at the monitors to note the airflow, temperature, and whatever conditions you require for the room. Make sure that you adjust the dampers at small angles.

Step 4: Note down the values

Take note of the optimal values for each room. And label each duct lever with the name of the rooms. This will help you in future operations.


While reaching for the levers, always be extra cautious. Wear safety equipment to prevent any scratches or injuries that might happen due to sharp objects. You can always reach out to professionals in air duct dampers to help you out. Follow our website for more interesting articles.


Joyce is Managing Editor overseeing the coverage of Senonches.

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