Troubleshooting Issues With HVAC Dampers

Published by Home Service Stars on

Does your home ever feel too hot or too cold when the seasons change? Most homeowners might assume that this is just your body needing to adjust to the changing temperatures, but then later may find it’s actually an issue with their HVAC system. If you find your HVAC just doesn’t seem to keep up with the changing temperatures, it’s likely because you need to adjust your HVAC dampers. 

HVAC dampers, also known as duct dampers, are movable plates inside your ducts. They help regulate your home’s airflow and redirect cool or hot air. We’ll go over some common issues caused by HVAC dampers and how to easily solve them without spending a dime. 

Troubleshooting Issues With HVAC Dampers

Aside from cooling and heating issues, there are some other common problems that could be because of your HVAC system. Even beginners can easily diagnose and solve these problems. Don’t worry if you’re not sure what’s wrong with your HVAC system. Common issues caused by HVAC dampers include:

  • Issues with airflow in some rooms.
  • Inconsistent airflow throughout your home.
  • Manual dampers in the incorrect spot.
  • Automatic dampers not adjusting. 
  • HVAC not produing the “right” type of air.

Most of the problems you can solve on your own, with either zero or little money spent to fix them. If you do have an issue you’re unsure about, you can always call Home Service Stars to speak with an HVAC professional in your area.

Also Read: How To Clean HVAC Coils

Where To Find Your HVAC Dampers

Not all HVAC systems use dampers. Zoning or zone control systems typically have dampers. If you don’t have this type of system and can’t find your dampers, you may not have them. There could be another issue with your HVAC system instead.

In most homes, you’ll find your HVAC dampers by your furnace. Your furnace system should have supply trunks and a ductwork system. This is how hot or cold air travels through your home. If you’re only having issues in certain areas of your home, make note of which rooms aren’t receiving the correct air. 

HVAC dampers are normally located close to the central unit. This should make it easy for you to find and adjust them. The damper handles should look similar to the ones pictured. Yours may look a little different depending on what kind of unit you have. 

Make note of how many dampers there are, and label which ones go to which room when you adjust them. 

How To Adjust Your HVAC Dampers

To get the airflow in the correct spot with the correct type of air, you just need to balance your dampers. Once you’ve found your dampers, make note of whether they’re manual like the one pictured or automatic. If you have automatic dampers that aren’t adjusting properly, you should call an HVAC expert to help fix the mechanism.  

Manual dampers have a small handle. This is used to open and close the ducts. All you need to do to “open” and “close” the ducts is to untwist the bolt and move the handle.

manual damper
To open and close your HVAC dampers, all you need to do is turn the handle as shown in the above picture.

Your HVAC system is likely set up in different “zones” of your home. This can help you direct air where it’s needed most, and can even help save up to 35% of your energy costs if adjusted correctly.   

Step One: Find An Assistant

Find someone to help and get a permanent marker. You can easily do this on your own, but it’s much easier with an assistant. With your assistant, make note of where all the vents in your house are, and open all the vents. You’ll want a strong airflow so your assistant can easily make notes when you’re testing. 

Carefully judge where you think each duct leads to. Tell your assistant to go to that vent, and turn your furnace on fan mode with the thermostat. You can always use heat or AC if your furnace doesn’t have this setting. 

Step Two: Confirm Where The Ducts Lead To

By moving the handle vertically, you’ll close the damper. If yours is different, be sure to label which position is closed and opened. Check with your assistant to see if there’s airflow in that room. If not, that damper could be leading to another room.  

Do this one damper at a time. Once you confirm where each damper leads to, label the damper by the name of each room.  

Step Three: Adjust The Damper For The Season

The best way to adjust your dampers is to start testing at the start of each season. Use sticker labels to indicate where to place the damper during which season. Be sure to bookmark our article so you can remember how to do this.

When the weather is warmer, you’ll want to close off the dampers leading to the lower levels of your home, like the basement. Heat rises, therefore, your basement and lower levels in your home won’t need as much airflow as the upper levels. You can also adjust your dampers so they’re only partially opened. On the other hand, all the rooms in the upper levels of your home should have fully opened dampers. 

When the weather is colder, you’ll want to get more airflow in the spaces you use the most. This will likely be the main floor of your home or in rooms you know will need more heat like a basement. 

It may take you a few days or a few weeks to get the airflow just right. Check each room daily to ensure the temperature is ideal, and make any needed adjustments. This is why we recommend sticker labels instead of permanent markers to do this.  

Also Read: Is Your Home Winter Ready?

Types of Dampers

If you had to manually switch your dampers, you should look into whether there could be another issue at bay. Here are some common designs for HVAC dampers. 

  • Blade dampers can regulate airflow in HVAC systems, chimneys, and ducts. These dampers are designed for control and strength. This makes the airflow easier to control and produces less noise. 
  • Butterfly flat dish dampers are highly efficient and low-maintenance. These dampers use multiple blades that can either restrict or completely stop airflow. They can prevent back-draft by only pushing air in a very specific direction. This is very useful for fire prevention. 
  • Guillotine dampers provide the best seal. They can completely block off airflow, which is great for homes that need to completely isolate the airflow in certain rooms. 
  • The inlet vane dampers provide better airflow and superior pressure control. They use multiple blades to “swirl” effect with the airflow. This can help with spaces that need full control over ventilation and airflow. 
  • Louver dampers are best for quick adjustments and strong blockaging. These are the most common type of HVAC dampers. 

There are two types of dampers you’ll find in HVAC systems.

Manual Dampers

Manual dampers use adjustable handles to change the airflow. You’ll have to adjust the levels on your dampers at the start of each season to optimize airflow. Manual dampers are durable and pretty low maintenance aside from having to adjust them. When you’re having heating and cool issues with manual systems, it’s likely because of the position of your dampers, which is a pretty quick fix. 

Manual dampers won’t automatically change to the perfect position. It may take some time to figure out where to position your dampers. These also aren’t remote systems, which can be a huge pain if your dampers are in a hard-to-reach place close to the ceiling. 

Automatic Dampers

Automatic dampers use motors to automatically change the position of the dampers when the seasons change. They’ll either automatically change positions, or you can do it with a remote. 

These dampers are designed to give your home the most optimal airflow based on the current temperature. This makes temperature control in your home seamless and more precise. However, if you’re having issues with airflow even after adjusting your automatic dampers remotely, there could be another issue with the motor or the thermostat.  

Questions About HVAC Dampers

If you need some more advice on how to adjust your dampers, what type of dampers to use, or which type of system you have, call Home Service Stars to get free advice from a local expert.

We work with only the best HVAC professionals and can connect you to an expert as soon as you call. Whether you’re having a problem with your system or just need an expert opinion, we can help you. 


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