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Should Ductwork Be Replaced After 20 Years?

Your ductwork does an important job. Not only does it regulate the temperature in your home, but it prevents allergens and dust and can also affect your energy bills. If you’ve moved into a home with an old system or just replaced your furnace, you may be wondering when your ducts need to be checked out. 

You should replace the ductwork in your home after 20 years or much sooner. Ductwork is usable for up to 20 years, but the effects of deterioration and long-term use minimize their efficiency around the fifteen-year mark. So, you should change your ductwork whenever you see signs of deterioration. 

Knowing when to replace your furnace or boiler may seem like a simple task, but your ductwork is essential to smooth energy consumption in your home. In the rest of this article, we’ll talk about the purpose of ductwork and why it’s not a good idea to let it break down. We’ll also talk about the signs of failing ductwork and the first steps to replacing it. 

When Should Ductwork Be Replaced?

Your ductwork expands, contracts, and can rust. Not to mention that dust builds, circuits become less powerful over time, and your furnace will be harder on your ducts the older your furnace is. Obviously, the ductwork needs to be replaced at one point or another. But when? Do you need to check it as often as an air filter, or can you go years without checking it like a furnace?  

You should replace your ductwork every fifteen years or sooner if you’re sensing some issues. Your ductwork can affect the efficiency of your furnace and the quality of your air, so it’s essential to get it replaced every fifteen years even if it appears to be in good condition.

Your system’s performance relies on the age of your furnace, which directly affects the health of your ductwork. It’s recommended that you change your furnace every fifteen years or so, but with all the new upgrades and energy-efficient models coming out, you may be better off doing it sooner. Regardless, you can kill two birds with one stone if you get your ducts inspected or worked on simultaneously as your furnace. 

Read: Ductwork Insulation: Everything You Need To Know

The Purpose of Ductwork

Ductwork is an often forgotten but wildly important part of any home.

Your air conditioner or furnace could very likely not function without ductwork. Ducts are the things within your walls or ceilings that transfer air from your furnace or air pump into the rest of your home. 

In the best of scenarios, efficient ductwork can change quite a bit for your home. It can make your energy bills lower, heat your whole house efficiently, and even affect the air quality of your entire home.

If you don’t have any ducts and are starting to get worried, don’t stress. Ductless systems are growing in popularity, and many high-efficiency systems are switching to a ductless model.

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Read: How Hot Can Ductwork Get?

The Consequences of Old Ductwork

If your furnace is running poorly, it’ll negatively affect the quality of your air ducts because their systems are intertwined. In turn, the heat, efficiency, and air quality will also decline. This isn’t the only thing that can affect the quality of your ductwork, though. Having furniture pushed in front of vents or keeping all the doors in your home closed can also reduce heat efficiency and even clog up your ducts. 

Even if you have a terrific, high-end furnace, your ductwork will sour your air quality if it isn’t replaced efficiently. The consequences can negatively affect your family’s health and flare up asthma issues in anyone who has asthma.

This YouTube video highlights how old ductwork will affect your furnace and your home: 

If having an old system isn’t your problem, but you have some suspicions that your system needs a replacement, this is possible, too. While some people may point you toward ductwork cleaning if your system isn’t ancient, it’s not always the right way to solve a duct problem. Air duct cleaning isn’t efficient for problems like mold and won’t solve your ductwork issues if your system is old.

Read: How Hard Is To Replace Ductwork?

How Will I Know When My Ductwork Needs To Be Replaced? 

When things go unaddressed, it can end up becoming a big problem. Who among us hasn’t ignored a clunking in their car just to find out if they had come to the auto shop a month earlier, there wouldn’t be an entire system to replace? Our homes, especially our HVAC systems, can feel like the same high-risk game of “is this a problem or not”. So, how will you know when your ductwork needs to be replaced? 

If you feel your ductwork isn’t performing efficiently, it’s making tons of noises, or it’s over fifteen years old, you should consider replacing your ductwork. Inefficient, failing ductwork will make temperature zones in your home inconsistent, raise your energy bills, and even emit a foul smell. 

If you’re worried about your ductwork, it may be time to call a professional to assess the system.

There’s no harm in getting a second opinion from a trusted HVAC expert, even if you’re unsure. You can attempt a few fixes by yourself, such as sealing leaks with duct mastic and checking for leaks, but a total replacement needs professional work. 

Read: Does HVAC Purify Air?

Signs of Failing Ductwork

A few tell-tale signs indicate that your ductwork is failing, inefficient, or obsolete. An easy indicator is its age. If your ductwork is over fifteen years old, there’s a good chance it isn’t working as it used to in its hay day, and a replacement might be in order.

As discussed, your ductwork is supposed to help warm or cool air travel efficiently from your temperature system and then control your home’s climate. If you’ve noticed that your home isn’t getting as warm or cool as it used to, you should check for leaks or see if your system has become inefficient. Additionally, inefficiency is a sign that your ductwork needs either some work or a complete replacement.

Changing your energy bills is another sign that your ductwork isn’t working as well as it used to. If your furnace or air system works hard to heat your home, it’ll be reflected in your energy bills. Different issues with your furnace can cause this problem, but it can also be your ducts. If you haven’t changed your usage, but your bill is going up, your ducts may be the culprit.

Another good indicator that your ductwork needs to be examined is a foul smell. It won’t always mean that you need a replacement, but it could indicate that there’s vermin living within your vents or mold growing. If even mild molding occurs, you’ll need to replace your ducts. 

Read: How To Increase Airflow In Ductwork

Next Steps For Getting New Ductwork 

Once you’ve decided you want to get your ducts looked at, you can call an HVAC professional in your area. Many states and counties have energy offices as a part of their government to help homeowners and business owners become more energy efficient. You can contact them especially if you don’t want to work with a professional who tries to sell you on something regardless of your problem. 

When you get the estimate for your ductwork, you can consider either entirely replacing your ducts or taking the opportunity to switch to a new energy system. There are tons of ductless options, which might be a good fit for you, depending on your priorities. 


You should replace your ductwork every fifteen to twenty years, but you should also examine it if you’re suspicious about its efficiency. Hard usage, mold, and a litany of other problems can reduce the average lifespan of ductwork, so look out for signs of an inefficient system.