The duct stops here
Ducts are the tubes that move air from your HVAC system to different parts of your home.
Newer AC units may require updated ducts in order to work efficiently (or at all).
You may be able to avoid replacing your ductwork as long as it doesn’t show signs of damage, corrosion, or pest infestation.
Both ducts and AC units tend to have a life span of about 10 to 15 years.
You may be able to repair certain portions of your ductwork instead of replacing the entire system.
If you’re about to replace your home’s air conditioning system, you may wonder whether you should replace your ductwork. Most ductwork lasts between 10 and 15 years, which is about as long as ACs last. So, if your AC and ductwork are both toward the end of their life spans—or several years older—it’s often worth replacing your ductwork with your AC.
However, you don’t always need to replace your ductwork when you refresh your AC. How can you tell which camp you and your shiny, new HVAC system will be in? Here’s how to determine if you need to replace ductwork when replacing your AC.
Your ductwork is, put simply, your system of ducts—the tubes, often metal, that allow air from your HVAC system to circulate through your home and get into every room. Without ducts, your air conditioner would be useless because the chilled or heated air wouldn’t go anywhere (unless, of course, you have a ductless AC unit, like a window unit or some types of mini splits).
Here are some scenarios in which you may need to have your ductwork replaced alongside your AC unit.
In a similar vein, your ductwork may simply not be the right size to fit your new HVAC system or air conditioning unit, in which case your unit’s performance may be compromised, and your energy bills might go way up. Under these circumstances, it can actually be more cost-effective in the long run to have your ductwork replaced.
Even very sturdy ductwork doesn’t last forever, and if your ductwork is damaged or corroded, having your AC replaced may be a perfect opportunity to replace your ductwork, as well. Some signs that your ductwork may be damaged include:
Higher-than-average energy bills
Strange AC unit noises or odors
Uneven heating or cooling throughout your home
Excessive dust in your home
Noticeable debris or dirt around your air vents
These signs could indicate leaky ductwork that might allow mold and bacteria to grow or even become infested with pests. Long story short: If your ductwork has gone bad, you’ll definitely want to replace it (even if you’re not getting a new AC unit).
Uneven heating and cooling can indicate a problem with your ductwork or be reflective of an outdated design or poor maintenance.
For example, maybe your home has an addition that’s newer than the rest of the home, and the ductwork to that addition was retrofitted after the fact. If the installation wasn’t done properly, the addition might not get the same kind of heating or cooling effect as other parts of your home, a problem that may require a wholesale redesign of your ductwork (or, at the very least, some repairs).
Similarly, previous patch jobs on existing dated ductwork systems can mean cracked, aged, or leaky ductwork that doesn’t properly heat or cool your home. Inefficient or outdated ductwork can make your HVAC work harder and still not heat or cool your home properly.
"Quality ductwork will increase the efficiency of your HVAC, sometimes even by 20-30%. This is so because there is reduced air leakage due to better insulation and more optimized airflow. Because this makes your HVAC work more efficiently, it really doesn't have to work too hard to keep the desired temperature; thus, its energy consumption is lowered directly."
— Yashar Mosaferi, President of Klondike AC, Casper, WY
If the idea of having your entire ductwork system replaced is making you sweat, rest easy: You may be able to simply have portions of your ductwork repaired instead. If your ducts aren’t very old or deteriorated, your local duct installer may be able to simply repair any problem portions and connect your new AC unit directly to your older duct system.
Keep in mind that your ducts will need replacing at some point, so it may make sense to do everything at once. The cost to replace ductwork can range between $455 and $2,180 while repairing ductwork costs between $130 and $2,000, on average. Prices will depend on the size of your home and the extent of the replacement or repair.
Usually, ductwork is not included when you purchase a new HVAC system; it needs to be purchased separately. As far as installation, you’d need to speak with your local duct installer or HVAC technician directly to learn what their services include, but having your entire ductwork system replaced is likely to be more expensive than simply having your new AC unit installed without ductwork replacement.
Most AC units, with the proper care, will last between 10 to 15 years, on average. Window units last between 8 to 10 years. You can extend the life of an AC unit by regularly replacing its filter, cleaning its coils, and scheduling an annual tuneup.
The best type of ductwork will vary based on a person’s budget, home, and the type of HVAC they install. Generally, sheet metal is considered to be the most energy-efficient type of ductwork; however, it tends to be expensive. Alternatively, flexible and fiberboard ducts offer some of the best insulation for an HVAC system, but they require more regular maintenance to stay in good shape.
