Testing Damper Issues | Replacement Cost Of HVAC Dampers

Test HVAC Dampers

Heating, ventilation, and air conditioning systems keep building occupants comfortable and safe. However, when one component does not work, people indoors will not feel the comfort they are expecting.

Therefore, HVAC dampers, like other HVAC components, are a crucial part that needs checking now and then.

How do I test my HVAC dampers? First, place the damper in the open position and check the registers to see whether airflow begins. It is most likely a poor damper if the damper is closed and giving little or no airflow. Next, turn on your HVAC system and check the registers for airflow.

Checking the damper can often be difficult, especially if you do not know what you are looking for. Therefore, before proceeding to test your dumper, you must be aware of how it works.

What Is An HVAC Damper?

Controlling the airflow in a room is usually as simple as adjusting the vent in that room. It appears to be the most sensible course of action.

However, you must change the vent angle if you wish to slow or halt the airflow completely. This method might work well, but it is not the most effective approach to manage airflow.

HVAC systems, it appears, are equipped with balancing dampers. These are simple mechanisms that you can use to seal off sections of a duct system.

However, you can spot the register where the duct meets the floor, ceiling, or wall. The damper is around 4 to 6 feet from the main duct trunk. Therefore, it is much closer to the central unit of your HVAC system.

So, how does closing this differ from closing a vent? Because it is closer to the center, that suggests you are shutting off a section near the air source, whether hot or cold. It will compel the system to reroute the air to another location in the house.

It means you get the proper amount of hot or cold air from the furnace or air conditioner. In addition, it makes the entire system more practical because it runs to keep your home at a comfortable temperature.

Some of you may ask how long these dampers last? While there is not one thing that lasts forever, there are things that can last a long time. One of these items is HVAC dampers. But then again, things could only last depending on how owners regulate it.

While your central air conditioning system is likely to be 15 years old, your dampers should last much longer. HVAC dampers are predicted to last for more than 20 years. Now that is a pretty long time.

Of course, like with any appliance, you might anticipate this number to be lower if you use it excessively or infrequently. If the dampers had been stock for years, they become clogged with airborne threats.

An AC with airborne threats is no longer safe. It will need extreme cleaning.

It is suggested that you do not switch them back and forth hundreds of times a day. The switching of dampers multiple times a day will put more stress and create wear and tear faster. Unless you are ready to waste money, never attempt this.

However, it is possible to have a long relationship with your damper. But only if you check it up once in a while and if you use it correctly. If you have not observed an issue in fewer than twenty years, there certainly is none.

You now know the basic things about HVAC dampers. Let us proceed to understand how they work.

How Do HVAC Dampers Operate?

This inquiry may appear to be a rehash. However, this part will cover the actual mechanism of the dampers and operations of both manual and motorized dampers.

There are two types of HVAC dampers: manual and automatic.

1. Manual Dampers

A manual damper features a lever outside the air vents and ducts, for example, rectangular manual dampers. It can operate the manual system plates and valves.

The majority of these dampers are similar, allowing operators to adjust airflow throughout the system. In addition, they are recognized for being long-lasting and can last for years.

Because the blades are easy to access and modify, these dampers are ideal for small establishments and residential locations. However, automatic dampers outperform manual dampers in terms of precision.

2. Automatic Dampers

Automatic dampers are well-known for their user-friendliness. It contains a small motor that controls the dampening plates and valve shutting and opening.

The capacity to control is the fundamental difference between automatic and manual dampers. The former can be controlled remotely and is ideal for a high-ceilinged facility, whereas the latter requires someone to adjust the valve.

Testing Damper Issues

In terms of monitoring airflow in your systems, zone dampers are usually quite reliable. There are times, though, when zone dampers fail and cause heating or cooling problems.

Several variables might create damper problems, but thankfully, systems tend to fail in predictable ways. System failure may not sound good, but this case is an exception. Moreover, it often makes the problems straightforward to diagnose.

Identify The Damper

First, you need to locate the dampers. You cannot modify anything until you have identified your dampers. For the most part, this should be straightforward. However, some readers may find themselves in situations where altering the dampers is not a possibility.

Some homes, especially newer construction, do not have balancing dampers attached to the ductwork. In all honesty, this housing is a terrible cost-cutting strategy.

Most modern home renovations, the dampers, if they exist, have been covered over by drywall in other homes. Shine a flashlight into all the ceiling vents in your finished basement.

It will allow you to see whether what you believed was a functional vent is an access panel.

On a more positive note, having a premium system will be easy for you to regulate the dampers. This system allows automatic HVAC damper regulation.

But, let us be honest, if you have this system, you are probably not reading this article. Most automatic dampers are taken care of without the need of you going through many troubles.

Furthermore, if you are not sure if you have one, look for miniature motors with wires connecting to your dampers. Do not look for actual handles, which may not exist in modern houses.

Aside from those two scenarios, finding your dampers should be simple. First, examine the main duct trunks extending from your furnace, whether in a utility room, crawl space, basement, or elsewhere. Installers usually place dampers between 2 and 6 feet from the main stem.

Troubleshooting Manual Damper

While the system is functioning, check the airflow of the registers. Observing any changes in airflow along the duct line will help you pinpoint the source of the problem.

Close a specified damper using the damper handle on manual dampers. Check the registers linked with that particular damper to see if airflow has stopped while the remainder of the system flows.

Then, reopen the HVAC damper and double-check the HVAC register. You have a damaged one if you feel airflow when the damper is closed or no airflow when the damper is open.

Troubleshooting Automatic Damper

Automatic damper troubleshooting is a distinct process. First, turn the system on and set the zone thermostats to a setting that ensures enough ventilation. Next, inspect the associated HVAC zone registers for airflow.

You may have a defective HVAC damper if you have minimal airflow, but the room does not keep its temperature. Another reason is you have lots of airflows, but the room is drafty.

In most cases, faulty dampers are among the least expensive problems you will encounter in the HVAC system. Therefore, the first step in diagnosing HVAC systems is to eliminate this issue.

Some damper issues can be subtle. Next is to determine if your damper needs replacement.

Signs Your HVAC Damper Needs Replacement

Checking whether your damper is working is the quickest method to detect whether something is wrong with it. This one is a simple procedure that does not necessitate the assistance of a specialist.

  • To begin, determine which zone the damper influences. Then, you can identify which areas of the house should be able to alter airflow. Next, follow the ductwork from the damper. Make sure you have easy access to these registers.

  • Decide whether the damper is manual or automated at this point. A handle for adjustments should be fitted to the ducting when using a manual HVAC damper. A motor controls an automated damper. If you do not know what you have, a visual inspection should reveal it.

  • Turn on your air conditioner and inspect the vents. It is a good indicator if the damper is open and there is airflow out of the register. But you are not out of the woods yet.

Check to determine whether there is an interruption of airflow by closing the damper. If that is the case, do not be concerned.

If your automatic damper appears to be in good operating order, do not replace it just yet. The HVAC damper itself may be in top working order, but the thermostat in the cooling zone is not. It indicates that the control panel believes the zone temperature is higher than it is. It is a simple test to perform.

  • Check to see if the thermostat is still operational. When you try to use it, does it turn on? You might be able to remedy your problem by just replacing the dead batteries. If that does not work, you may need to replace the thermostat.

  • Examine the settings of the thermostat. The thermostat’s internal thermometer is a crucial component that can stop working the way it should be over time.

    Also, purchase a low-cost thermometer and place it close to the thermostat. The next time the room is cooled, leave it there. Check to see if the room is at the proper temperature when the HVAC stops pushing air.

  • Check the primary settings once more. There is always the possibility that there was a misunderstanding during the installation of your automated dampers.

    Check to see if the room in question is in a separate cooling zone. If that is the case, you are dealing with a programming issue.

If you feel that it needs replacement, below will be an estimated replacement cost.

Replacement Cost Of HVAC Dampers

The cost of replacing your damper motor will range from $200 to $500. Therefore, a new motorized damper might cost anywhere between $100 and $200.

A contractor will need about two hours to complete the installation, with labor charges ranging between $150 and $300.

Factors Affecting The Cost Of Replacing HVAC Dampers

Are you unsure how much it will cost to replace your damper motor? Here are a few factors to think about that could affect the total cost of the part and installation.

1. Damper Motor Model And Maker

Damper motors are the same. Again, there are many brands to pick from, each with its size, shape, and voltage.

Although their fundamental function is the same, their efficiency and pricing will differ. However, ticket price should not be your only consideration. In addition, different damper systems necessitate distinct damper motors.

Therefore, it is advisable to consult an HVAC specialist to ensure you obtain the correct damper motor for your unit.

2. Labor

The time it takes to remove and replace will depend on the severity of the damage. In addition, your specific location and surroundings, like previous installations, can make the work easier or more difficult for your specialist. As a result, labor prices can fluctuate.

Some people do not have the money for professional replacement. So, to help out, here are ways to replace the dampers yourself.

Do It Yourself HVAC Damper Replacement

  1. Locate the existing dampers in the basement ductwork. You should see it either on the supply side of the furnace plenum or in the register boot.

    Check for support in the first section of ductwork closest to the damper, such as brackets, hangers, straps, or wires. If it does not work, add a support strap.

  2. With a utility knife, score the duct tape or foil on each side of the damper. One end will link to the register boot or plenum collar.

    The other will connect to a duct section or maybe an elbow. Using the scoring in the tape, remove the sheet metal screws. Alternatively, if it is loose and flaking, tear it off and undo the screws.

  3. Remove the nearest duct segment from the damper and suspend it carefully. Next, remove and discard the old damper motor.

  4. Brush mastic around the crimped edge of the damper. This process will provide significantly better air leak prevention than duct tape. Afterward, you may wish to retrofit your other duct parts as well. Finally, brush the duct or crimped boot surface as well.

  5. Slide the new crimped damper side into the register boot or the uncrimped end of your stiff, circular duct section. Face it away from the plenum collar. When the damper is open, the crimped end should point away from the furnace. It will allow the air to pass through the seam without leaking.

When using an automatic damper, keep an eye on the motor location actuator and spin the damper motor as needed. Set the motor actuator on the top or side of the duct for horizontal ductwork.

Reminder, do not put it on the bottom. If you set the damper vertically under a register, you can put the motor actuator wherever you choose.

  1. Press the uncrimped dumper side into the other side of the duct run. It will either be a start collar or the crimped end.

  2. At least three sheet metal screws, or more for large-diameter dampers, should be used to secure each end of the damper motor.

  3. Apply additional mastic to the joints. Paint another coat of mastic on the tape and the seams of the damper after embedding fiberglass mesh tape in the coating.

Do I Need To Ask A Specialist To Replace My HVAC Damper?

The question of whether or not to hire a technician boils down to one of money versus time. Damp replacement is not a dangerous job.

The only things at risk are time, strain, and parts if you follow standard safety precautions. But, for peace of mind, if you are not sure about something, call a technician.

The parts for an HVAC damper replacement can be as low as $200. However, a professional installation can cost up to $500.

The price you pay will vary from the local companies, your specific ductwork configuration (including accessibility). Also, it will depend on whether or not it is part of a larger maintenance project.

If you’re still not certain after reading this article, it is understandable. You may not have enough confidence to replace your ductwork.

Or it might not be worth the risk. But it is significantly more expensive to damage parts or your ductwork than to hire a professional.

Take Advantage Of Your HVAC Dampers

Individual Testing

Ensure that the vents are all open before starting. Try to find a friend or family member who can help you out. Let them stand beneath the vent at the opposite end of the ducting.

Power up your furnace blower by putting it to fan mode or turning on the heat or air conditioning. Next is to close one of the dampers by moving it to the vertical position.

However, it would be more convenient if you have someone to stand beneath the vents at the other end of the ducting. It would be easier to report on the airflow this way. Alternatively, if you are alone, you will have to get there alone.

You have closed the damper that controls the air from the building to the location with little air coming out. It is a good idea to name the duct after successful identification.

First, write the room each damper controls. After that, repeat the same with the second damper.

Seasonal Adjustments

You can adjust your dampers based on where and when you want the air to flow. However, we suggest doing it once you have determined the position of the airflow. Because warm air rises and cool air descends, you will want to follow these instructions:

During the winter, close the damper to the upstairs. The heat will be forced downstairs, keeping the lower levels warmer. Warm air rises, so it will eventually find its way upstairs to keep those rooms warm.

During the summer, close the damper to the downstairs and basement. It will force the air conditioner to the top level. It will also boost the cooling impact in the rooms that get the hottest during the summer.

Cool air will continue to flow down to keep the ground floor and basement from becoming overheated.

Overtime Monitoring

Of course, personal choice plays a role in comfortable temps. After devising a technique for managing your dampers, track the results over time.

It could take several days or weeks to find the correct mix. To further reduce the airflow, you might want to consider closing dampers partially rather than as a whole in some circumstances.

Another technique to fine-tune the operation of your HVAC system is to open and close vents in certain rooms or zones, using the same method as the dampers described above.

Switch The Dampers Back Every Season

Some people forget to switch them back and forth each season. As a result, adjusting the dampers to enhance airflow will be a short-lived success.

There are things you can do to remind you to change the dampers every season. For example, you can set an alert on your phone, write dates on a calendar.

You can also keep a calendar near the furnace where you change the air filters. These are all effective ways to remember to change the dampers every season.

Remember that moving the level vertically up and down closes the damper. The horizontal movement opens it and allows air to flow through.

So far, the advice you have received has focused on changes you would like to make during the summer and winter seasons. First, make that the damper has the appropriate labeling. It will be easy to alter these in the future.


If you are still confused about what to do or unsure, it is always best to call a professional. If you experience any cooling or heating issues, calling an HVAC contractor can make your problems fade.

You can also check for evidence that your damper is the source of the problem using the guidelines above.

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