How to soundproof heating ducts? If you have heating, ventilation and air-condoning systems in your house, you might probably ask the same question.
This is because, in many instances, HVAC systems may allow noise or sound to travel to almost all parts of the house.
The part of the system that does this is the duct system. This component of the entire system provides passage for the air to circulate throughout the house.
The heating duct is known to cause noise. The sound travels through the entire system and therefore reaches different parts of the house including the library, movie theater, master’s bedroom, etc.
In most cases, the noise causes disturbance to movie watching, reading in the library, or to your sleep.
If this bothers you every day, you might be wondering how to curtail the sound.
So how to soundproof heating ducts?
There are many ways to soundproof heating ducts. One of the best strategies is using the lining ducts with duct liner. This is a great way to inhibit the sound from traveling throughout the length of the duct system.
What is a Heat Duct?
Before diving into the techniques on how to soundproof heating ducts, let’s first talk about what is a heating duct.
As mentioned, a heat duct is a part of the HVAC system that provides an air path throughout the home or commercial spaces.
In most cases, a heat duct is made of round or rectangular tubes that made up the entire branching network.
Heat ducts are made of metal sheets, fiberglass duct board, or insulated plastic. These materials are installed within walls, ceilings, or floors.
What is the purpose of a duct heater?
Duct heaters, as the name suggests, serve as air flowing ventilation systems that regulate the temperature of the room or indoor spaces.
This system provides temperature during winter or cold seasons.
However, because ducts are made of round or rectangular tubes, the same structure has a drawback.
One of the common problems is noise distribution. The sound travels through the duct system that reaches all corners of the house.
This invades the quietness of the house. For many years, this problem was something I constantly dealt with at home.
The situation was we had a home movie theater located in the basement of our house where we regularly watch movies.
But the problem was that the sound from the basement freely traveled through the heat registers that reaches all over the house.
By the way, I used the metal heating ducts.
The funny thing is that the sound could be clearly heard in other parts of the house almost like being in the movie theater.
Needless to say that the sound is loud and clear. The sound from the bass had a worse impact. As a result, we couldn’t increase the volume of the speaker to keep the disturbance minimal.
This was a huge problem back then. If you have children in the house, the problem can be worse than what I used to experience many years ago.
I did a lot of research hoping to find a solution. Unfortunately, even the contractors nearby, the ones who install HVAC systems had no idea how to solve the problem.
So I started experimenting. The strategy that I found effective for me was lining the ducts with duct liner. This strategy stops the sound from traveling from the register to the other end of the pipe.
The other way that I found useful is using acoustical ducts instead of using regular pipes. But this is only possible if you have access to the ductwork.
This process though can be arduous and time-consuming on your part. But it is definitely worth a try if you can.
You can also use Dynamat. This material is a great sound blocker. You can install it inside the duct where the sound enters.
Dynamat is a sound dampening material that blocks the vibration on the metal sheet.
If you are currently constructing your basement, you can add Dynamat Extreme all over your ductwork. This worked well for me too. The sound decreased to almost unnoticeable.
Additional Effective HVAC Sound Insulation Techniques
Some HVAC contractors actually give useful tips on how to install a duck work system that does not produce noise or disturbing sound.
However, these techniques only work if you are currently constructing the HVAC system. But if you have a noisy heating duct, there is not much you can do other than soundproofing.
Here are the HVAC Sound Insulation Techniques
There are two things you can do:
1. Use a Large Return Duct
There are many reasons as to why return air ducts produce noise. One of which is the size of the material being used.
Undersized air duct or register is one of the common sources of noise or disturbing sound.
So the solution is to use a large return duct. The recommended size is 14” in diameter. This should reduce if not eliminate the sound created from the airflow.
2. Use a Long Insulated Flex Duct
The second doable and effective way is to install the long insulated flex duct in a snake form between the furnace and the return box. But make sure that there are no sharp bends.
Although these techniques are only suitable during the construction of the ducts, in some instances, they can be applicable to a finished structure only if you have access to the system.
If you have access, that gives you an opportunity to fix it by replacing the duct with wider and longer duct.
Related Question:
Is an insulated ducting quieter? Yes. Insulated ducting decreases the sound that is coming from the airflow. In addition, it also decreases radiant heat.
Final Thoughts
Soundproofing heating ducts, like other soundproofing projects, can be challenging. It may require not only soundproofing materials but also creativity and patience.
In fact, everything I learned from my projects is the byproduct of being patient.
I would like to emphasize here that I am not an expert in soundproofing. Everything I shared in this post is coming from my experience and research.
Furthermore, I don’t guarantee that every technique I mentioned will work. There are many factors that could determine the success of any soundproofing project.
Nonetheless, I hope that the tips I shared on how to soundproof heating ducts in this article will help you to make your heating ducts quieter.
For more information, don’t forget to visit my Soundproofing Guide.
