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Insulation Coming out of Vents | Reasons and Solutions

It can be concerning to find insulation at the entrances and exits of your HVAC vents. Something has almost certainly gone wrong!

However, if you’re in this situation, don’t worry, we’re here to help! This article will cover everything you need to know about why this is occurring, as well as how you can be sure of the root cause and take the necessary steps to fix it.

Insulation can come through vents that have been chewed by rodents, damaged by falling objects, or worn by time. Insulation can also enter the ducts during repair or maintenance of the ducts.

Rodents Have Made Holes in the Ducts

Sometimes, rodents will make their way into spaces in the home where ducts are found, like attics and crawl spaces, because of the shelter and warm temperatures (which can be made worse by bad venting).

Unfortunately, rodents being in these spaces can lead to damage and issues in your home, including holes being created in the ducts.

Rat inside a flexible duct

If your ducts have holes from rodents chewing them, insulation from the room around the ducts and from the ducts themselves can fall through the holes or be pushed through by the rodent, air current, etc.

This is especially true for duct insulation and loose-fill insulation. The duct’s insulation would be nearest and also chewed small enough to fall in, and loose-fill insulation is made up of small pieces.

From there, the insulation can enter your ductwork system, be blown around inside the ducts, and ultimately end up coming out of your vents.

Concurrent Signs

One thing that may indicate this is happening is hearing noises made by the animal moving around in your attic or crawl space, especially at night, since many rodents are nocturnal.

If this is happening, you will also find rodent droppings or notice an unpleasant odor from the animal’s urine in the attic/crawl space.

A more subtle sign involves household pets. If they are acting strange for seemingly no reason, it could be that they are sensing other animals in the home.

You would likely notice that your HVAC system was functioning differently if it had a hole in it, although this wouldn’t necessarily indicate rodents as the problem.

The changes you’d notice in your HVAC’s functionality include an overall decrease in efficiency, as well as inconsistent temperatures in your home.

Confirming the Reason

It is simple to find out for certain that this is happening. All you need to do is go into your attic or crawl space and inspect the ducts.

If this is occurring, you should find holes in the ducts where the rodents chewed them. In addition, you may find nests, droppings, or urine as I mentioned before.

Solution and Prevention

Ideally, if the holes are large, the best solution long-term would be to replace the entire duct (or section between two elbows). However, there are other options.

It is possible to seal the holes, but it should be done properly to ensure the seal will last and work effectively.

One way you can cover up the holes is by using foil tape along with applying duct mastic for good measure.

It’s important to note that you cannot use regular duct tape to seal the duct, as the heat and nature of the ducts will cause the adhesive to wear down quickly.

You can also attach a metal sheet over the hole in the duct, but this is slightly more complicated.

To prevent rodents from getting to your ducts, it’s important to perform routine maintenance, as well as use rat traps or other rodent deterrents to keep them away.

Holes and Splits Caused by Mechanical Damage

Holes and tears in the ducts can also happen from other causes. This can include natural causes, as well as accidents that lead to damage.

For example, other items or home infrastructure may fall on top of the ducts, causing damage like holes or splits.

In addition, over time, the ducts will experience normal wear and tear, and holes/splits can be a part of the normal wearing-down that occurs over time.

For air conditioning ducts, condensation can form at the edges of the ducts due to the cold temperature of the air, which can lead to rust.

The bottom line is this—there are several things that can happen to create holes through which insulation may fall and end up in your vents.

Concurrent Signs

The only sign that this is happening will be changes in the performance of your HVAC system, similar to the issues I mentioned for holes created by rodents.

The main things you’ll notice are uneven temperatures in the home, poor performance, odors, strange noise, and an overall decrease in efficiency of the HVAC system.

Confirming the Reason

To figure out if this is your issue, inspect the ductwork. Look for signs they aren’t working, and use your hand to feel for air escaping from the ducts.

Man wearing a personal protective equipment, inspecting the ducts using a light

Unfortunately, this may be time-consuming because the damage could be anywhere along the length of the duct and there are many different things you could be looking for.

In short, you should inspect every inch of the HVAC ducts and look for anything that seems out of the ordinary.

Solution and Prevention

In these situations, the solution is dependent on the circumstances.

In the case of items falling onto the duct or normal wear and tear causing holes, you will need to replace the entire duct, or repair the hole.

Please refer to the previous solutions section for further information on this fix.

In the case of rust, the solution depends on how long the rust has been present. It may be fixable without replacing the entire duct if its caught early, but if it has spread you will likely need a new duct.

Unfortunately, there isn’t a lot you can do to prevent these issues, as they stem from natural occurrences and random accidents.

What you can do is consistently perform maintenance and make a point to routinely check on your HVAC system to ensure it’s working correctly and damage-free.

Poor Installation or Repairs

If you have recently had a professional install your ducts or do repair work on them, then this may be the cause of the insulation getting in your vents.

If the ducts aren’t fitted properly at the joints, it can leave spaces and cracks where insulation can get into the HVAC system.

In addition, it’s possible that the insulation was pinched between the joints while the ducts were being worked on.

Insulation isn’t likely to be pinched during installation because insulation is laid down after ductwork is installed.

However, it could be possible for this to happen after a repair, as the ducts will be worked on and altered while insulation is present.

Concurrent Signs

As always, the main sign of this happening would be performance issues with your HVAC ductwork system.

If you’ve noticed any issues with temperature, unusual sounds coming from the system, unpleasant odors, or any other strange occurrences, it’s possible something was done wrong when working on the ducts.

Man holding his nose because of the bad smell coming from the ducts

Please note that this alone doesn’t indicate that installation or repair issues are the problem. To figure that out, refer to the next section.

Confirming the Reason

It is tricky to confirm this as it’s hard to identify installation/repair mistakes if you don’t have advanced knowledge of HVAC systems.

My suggestion is to think about the signs that something is wrong, and think about the time frame in which those signs have presented themselves.

Were your ducts newly installed? Did someone do repairs on your duct system right before you started having trouble? Compare events to see if it makes sense for this to be true.

Otherwise, you can just go along examining all the joins in your ductwork. It will be quicker than looking for splits and holes because you only have to look at the joins.

Solution and Prevention

If you are able to confirm this as your main issue, you will need to hire another professional to come and assess what’s wrong and fix the issue.

Unfortunately, there isn’t a low-cost way to combat this issue, and since the work was done incorrectly the first time you will want to invest in making sure they are fixed properly this time.

When it comes to preventing this issue, human error is something that’s hard to prepare for. However, there are still a few steps you can take.

Before hiring someone to install ducts in your home or do repairs for you, do some research on your available options before choosing someone to work for you.

Look at online websites and reviews, explore the newspaper or business directory for your town to look into every option possible, and ask family and friends if they have any recommendations.

Vents Blowing out Dust | Reasons and Solutions


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