Atlas AC Repair, LLC

Austin – Dallas – Fort Worth – Houston – San Antonio

Ductwork Replacement Cost Guide

The Cost to Replace the Ductwork is on Average $594.00 per Duct Run

Ductwork Replacement Cost Guide

Complete Ductwork Replacement Cost Guide
  • New Ductwork Cost – $694.00
  • Upsizing Ductwork Cost – $577.00


If you are looking to replace your system, its important to consider replacing your ducts as well. Ductwork may get dirty over time or you may have tears in the ducts themselves from wear and tear over time. A good rule of thumb when considering ductwork replacement is, if you have any cold or hot spots and your unit is not keeping up, it is worth it to get your ductwork checked out.  If your ducts have kept up but are getting old, its good to look into replacing them every 20 to 40 years depending on the type of duct. 

Ductwork Cost by Type

There are two types of ducts, flex and steel. Flex ducts are made from flexible materials that allow the duct to bend and fit through tight areas. Steel ducts are typically fixed into one permanent position and do not have much if any mobility, these are typically used for Commercial spaces. To replace a damaged duct it will cost you around $577.00, to upsize an existing duct it will cost you $594.00. A new duct run would run $694.00. To calculate your total ductwork replacement cost, take the type of service you need and multiply it by the number of ducts needed. 


We don’t replace metal ducts as most residential buildings in our service area are set up for flex ductwork. Metal ducts do have their benefits, they are more durable and longer lasting, have less air resistance and cant be chewed through by rodents. However, they are much more labor intensive due, you have to properly seal them to make sure they are air tight. Metal ducts also have to be insulated separately, which further increases the ductwork installation cost.  Metal ducts are also prone to rusting which can lead to indoor air quality issues. Although they do have some benefits, in our opinion the cons of metal ducts tend to outweigh the pros. 


Flex ducts tend to be the most common duct type used in residential settings. They are cheaper than metal ducts by about 40-50%, are less labor intensive and can be pulled through tight spaces that metal ducts would not work fit through. This allows for more ductwork if you are looking to convert your garage into a separate room or need more air flow in another part of your home. Flex ducts are corrosion resistant and can not rust. However they do have their cons, flex ducts have more air resistance than metal ducts and can be chewed through. In order to properly budget for the cost to replace HVAC ductwork its important to find the balance between the pros and cons of both types of ducts. 

Upsizing Ductwork Cost

Sometimes you may not need all new ductwork, you may just need your ductwork sized properly to your system. This happens commonly when the system size has been increased but the ductwork has not been upsized for the new, bigger system. When you have ducts that are too small, you can run into several issues such as reduced airflow which can lead to AC unit or Furnace issues. This causes increased wear and tear and can lead to expensive breakdowns. With ducts that are too small you will also experience increased noise due to the air moving at higher speeds, pressure imbalances which can lead to drafts in certain areas, and a reduced system lifespan due to the system being overworked. It’s important to realize that setting a budget for the ductwork installation cost can increase your systems efficiency and your air quality. 

New Ductwork

If you are needing to add completely new duct runs to your space, it will cost you $694.00. A new duct run will include new flex which is the duct itself, the collar which connects the flex to the plenum, the boot that connects the flex to the grille, and a new grille which is the vent that distributes airflow to the room.  The total ductwork cost will be dependent on how many new duct runs you are looking to get, to calculate it you would take the amount of new duct runs you need and multiply it by the price $694.00.

Existing Ductwork

If your ductwork is worn out and you are needing to replace existing ductwork it will cost you $594.00. An existing replacement includes new flex and collar. The flex will replace the old, worn out ducts themselves and the new collar would ensure a secure connection to the plenum. 

Upsizing Ductwork

If you are looking to upsize existing ductwork, it will cost $577.00 to upsize one size. A single size increase will come with a new flex, collar and reducer. The reducer will act as an adapter and connect the existing boot to the new flex. For example, if the original duct is 7″ and you are upsizing to an 8″ duct we could connect an 8 to 7 reducer so the new duct can fit the old boot. If you are upsizing more than one size it will run you the same price as a new duct run, $694.00. This is because when you are increasing the size that much, you will need a whole new boot and grille to ensure proper airflow in that duct. 

Damper Cost

Sometimes your ductwork is in good condition and you have the proper amount of supply vents but are still facing some imbalances. One way to address this without adding extra ductwork is to add Dampers to your duct runs. Dampers are plates that control air flow in a system into different zones. Each zone in the system is equipped with its own thermostat to regulate air flow base off of that areas specific temperature needs. There are several types of the dampers such as Zone Dampers and Air Balancing Dampers. Both serve their individual purposes but are typically combined together in order to properly maximize the value of your ductwork cost. 

Zone Damper

Zone dampers are typically added by the supply plenum, their function is to control airflow into the entire area. For example someone will adjust the thermostat, and that respective zone damper will open or close the vent accordingly. These dampers are automatic and help energy and cooling efficiency. 

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Air Balancing Damper

Air balancing dampers focus on making sure the airflow is balanced. These dampers are placed more towards the grilles of the ducts and are semi permanent solutions. This means they typically will not adjust automatically and once they are set you can have to take apart some ductwork to change their positioning. These dampers are put into place to guarantee even airflow from the flex to the grilles. 


CFMs or Cubic Feet per Minute is a measurement of how much air an HVAC System can move per minute. Each system is rated for a certain amount air flow and the appropriate sized ductwork is required. It’s important to contact an HVAC professional to properly calculate CFMs and size your ductwork as proper sizing guarantees system efficiency and the best comfort. Knowing your CFMs can help you properly budget for your ductwork replacement cost and give you peace of mind that your system will be performing to the best of its ability.

Duct SizeAirflow


You never want your ducts to be too small, when your return air is undersized the system cant pull in enough hot air to cool down. This leads to hot and cold spots and can cause the system to be constantly running to properly cool the space. This constant operation can cause system breakdowns that lead to expensive repairs or replacements. Since the unit is overworking itself, you will also have increased noise and utility bills as well. Properly sizing your ducts prevents these issues from happening and allows your system to work efficiently.

Too Big

When your ducts are too big, the system will only ever push out a set amount of air, if the air is not enough to match the size, you will have reduced air velocity and that can lead to hot and cold spots. This is because the air essentially becomes wasted since it is sitting in the ducts. Properly sizing your ducts are extremely important to your systems lifespan and your comfort.

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