Cellulose vs Fiberglass Soundproofing: Which is Better?

Cellulose vs Fiberglass Soundproofing
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Cellulose vs fiberglass soundproofing, which is the real winner? In this post, I will be discussing these two materials and their characteristics. If you want to learn more, feel free to read the whole post.

Cellulose and fiberglass are two of the most well-known soundproofing materials. In fact, if you have been in the soundproofing projects for quite a while now, you might probably hear these materials.

But if you are a beginner to soundproofing, you might be wondering which of the two materials is actually better.

When comparing cellulose vs fiberglass soundproofing, which one really works? Well, I think that these two materials share certain similar characteristics. However, there are major differences that separate these materials from one another.

For instance, fiberglass does not absorb moisture as much as cellulose. This is because it is made of synthetic materials, unlike the cellulose that is mainly made of organic materials.

In terms of installation, for better results, it takes more cellulose to insulate a room. The denser the cellulose the more effective it is. And when installed wet, it usually takes time for the material to completely dry.

These are just a few of the differences between cellulose and fiberglass. But there are more and subtle differences between the two.

The Differences between Cellulose and Fiberglass Soundproofing

In this section, let us discuss the differences in a little bit detailed way. Let’s start with cellulose insulation first.

Cellulose insulation is known for its ability to prevent conductive heat flow. This material is made of almost organic ingredients such as recycled materials. And due to its composition, cellulose is environmentally friendly and cost-effective.

Cellulose is not only effective insulation but also soundproofing material. you can apply it in your attic and other spaces you want to soundproof or insulate.

The second material that is commonly used for insulation and soundproofing is fiberglass. Like cellulose, fiberglass is also commonly used to insulate attic or other areas of the house.

But unlike the cellulose, fiberglass is made of synthetic materials making it less environmentally friendly. However, like the cellulose, it is one of the most cost-effective soundproofing materials you can use for your project.

The fiberglass does a very good job of containing warm air. Not only that, but it also blocks outside noise and soundproof space where it is installed.

Cellulose vs Fiberglass Soundproofing: Quick Comparisons

Here is the quick overview of the differences between cellulose and fiberglass:

Main similarities

  • They are both soundproofing materials
  • Both insulation materials
  • Versatile and can be both used for different home improvement projects

Main differences

  • Cellulose is organic; fiberglass is inorganic
  • Color differences (cellulose is grayish-white while the fiberglass is pink)
  • Differ in R-value and weight

Although these materials slightly differ from each other, they both captured the attention of people especially those who are looking for a quick and effective solution to noise.

The additional thing that makes people use either of the two is energy reservation purposes. If you are looking for ways on how you can minimize your electricity consumption, these materials can help.

Both materials could serve several benefits but in different ways. To help you decide which one you should buy for your soundproofing project, I further discuss the difference between cellulose and fiberglass below.

Detailed Comparisons between Cellulose and Fiberglass Soundproofing

Aside from basic differences that I have mentioned above, there are other features that these materials also differ or similar in many ways:


If you already have used insulation materials for your project before, you might notice that these materials have R-values. These values pertain to the ability of the materials to block thermal transfer. The higher the R-values, the better they are in insulating the space you want to insulate.

Interestingly, both cellulose and fiberglass have the same R-values. The values could range from 3.5 to 3.7. The changes depend on the part of the house where the materials are installed.

The other factor that could also affect the R-value is the way you install these materials. For instance, if you install any of these materials densely or loosely, the R-value may change.

In like manner, using cellulose and fiberglass in areas with extreme cold temperature, the R-values may diminish. You’ll notice this change both with cellulose and fiberglass.

Air Leakage

If you are looking for a material that will block or prevent air circulation, either cellulose or fiberglass is not effective for the job.

The cellulose, however, can slow down airflow especially when it is installed on the walls. But if you applied in your attic, the material is ineffective in blocking the wind that flows from the outside.


In terms of the installation process, both materials are installed in different ways. For instance, the fiberglass installation process is in two forms, batts and blown-in.

Most people prefer the batts installation because it is much easier than blown-in. But it is not without drawbacks. The batt installation is prone to errors and ineffectiveness. This is because it requires a lot of cuttings around the electrical outlets, wires, and pipes which create gaps. If this happens, the results will not be as you desired.

The blown-in installation, on the other hand, is more difficult and requires technical skills to get the job done properly. It usually involves the use of a machine to pump the loose insulation into the wall cavity to fit everything in place.

As you can imagine, this process is more difficult and arduous. However, if done correctly, you’ll get better results.

Cellulose requires only one installation technique, the blown-in. However, this strategy can be more difficult when done with cellulose than with the fiberglass.

Using any of the two materials may require a technical know-how. If you can’t do it your way, then maybe you can seek help from professionals to do the job for you.


If you are hiring professionals to do the soundproofing or insulation job for you, the costs may be similar for both materials.

The blown-in installation for both cellulose and fiberglass may cost about a dollar per square foot. The fiberglass batts installation, however, is less expensive. The common costs may vary between $0.30 to $0.50 per square foot.

But of course, the price may vary depending on the geographical location you are living in. Different contractors may have different price ranges on their service.


In terms of fire-resistance, cellulose and fiberglass have varying strengths. Fiberglass is known as a non-flammable. This is because it is made of synthetic fiber materials or glass.

However, under extreme heat, the glass may melt. This means that the fiberglass has a certain ceiling in terms of its capability to stand against fire.

In like manner, cellulose can also be flammable when exposed to the extreme heat. This is unsurprising because this soundproofing or insulation material is made of recycled organic material such as paper.

The paper components were treated chemically to make the material stronger and resilient to extreme environmental conditions. But the same ingredient makes the cellulose vulnerable to fire.

This tells us that, both materials can be flammable when exposed to extreme heat like fire. This is something that we should remember when using these materials in our homes.

Health Issues

More than a decade ago, health issues were once a concern of many homeowners regarding the use of fiberglass insulations. It was believed that this material contained a cancer-causing ingredient which caused some fears.

The fear was coming from the fact that, when fiberglass dries, the fibers could become airborne if disturbed. This usually happens during the insulation process. When airborne, the small fibers could be inhaled which, overtime becomes a health risk.

Thus, if you are installing fiberglass, it is very important that you protect yourself first before anything else. Wear protective gear such as a mask to avoid inhaling the airborne materials.

But if the fiberglass is installed correctly, it will not cause any threat to the people living in the house. The caution should only be considered during the installation process.

The cellulose, on the other hand, has no health threat issues. This is because the cellulose is made of organic and harmless materials.


Both cellulose and fiberglass are designed to last long. To prevent rot and decay, the cellulose is undergone chemical treatment. As a result, this material is resilient enough against moisture.

The fiberglass, on the other hand, because it is mainly synthetic, it does not rot or decay. But the only problem is that when compressed due to moisture it will lose its R-value. In other words, it loses its ability to block thermal transfer.

Environmental Issues

When it comes to environmental impact, the cellulose is a safer and more environmental friendly. It is made from recycled papers making it biodegradable and harmless to the soil and air.

The fiberglass, when dried could become airborne that may cause some health issues. And because fiberglass is synthetic, the production process also contributes to air pollution.

Extreme Temperatures Resiliency

Cellulose and fiberglass react differently to extremely cold temperatures. When exposed to the freezing point, the fiberglass loses its R-value by half. Thus, if you are living in areas that experience below-freezing temperatures, I don’t recommend using fiberglass.

Cellulose, on the other hand, has no problem with cold temperatures. It does not lose its R-value even when exposed to below freezing temperatures. This makes cellulose more resistant to extreme cold temperature than the fiberglass.

If you are living in cold areas, using cellulose rather than fiberglass is a good idea.

Final Thoughts on Cellulose vs Fiberglass Soundproofing

Cellulose and fiberglass are both soundproofing materials with both strengths and weaknesses. I strongly believe though that either of the materials has perfect use. So before buying any of the two, you should know first the soundproofing needs for your project. This way you’ll be able to choose the best soundproofing material.

I hope that this post helps you figure out the material you need. Also, I hope that you’ve taken important information about how cellulose and fiberglass differ from one another.

Frequently Asked Questions about Soundproofing

Aside from knowing the difference between cellulose and fiberglass, people also ask many questions about soundproofing. The following are a few examples:

  1. What is the difference between soundproofing and acoustics? Soundproofing is the process of keeping the sound in the room or blocking the outside noise. Acoustics, on the other hand, is the process of preventing the sound from bouncing off or echoing. Both soundproofing and acoustics are crucial in music recording.
  2. Is it really possible to create a soundproof barrier? Absolutely. With the appropriate material and strategy, you can build a soundproof barrier. You just need to know the characteristics of the soundproofing materials you’ll be using. Doing so allows you to achieve the desired results.

To learn more about soundproofing, just feel free to visit my Soundproofing Guide.

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