Is Fiberglass Insulation Good For Soundproofing :Flammable, FireProof, Combustible?

What is Fiberglass insulation and is fiberglass insulation safe for Soundproofing

When deciding to soundproof your house, is fiberglass insulation really a great choice? Or you need any other installations such as Rockwool or Roxul.

According to the US Energy Department, around 47% of US houses use many types of insulation, and around 25% of them use fiberglass insulation in their houses so Is fiberglass insulation safe???

Now, that proved that you can trust it but do you want to know about my experience after installing fiberglass insulation in my house?

What problems I have faced when installing it and how do I feel right now? Is my electricity bill went down or am I successful to make my house fully soundproof.

In this guide, I have shared all my experiences with trustworthy information about what is fiberglass insulation, hits ingredients, types of fiberglass insulations, and so on.

It’s going to be very interesting!. So let’s first begin with what is fiberglass insulation is.

What Is Fiberglass Insulation?

Fiberglass insulation is a thermal and soundproofing material. That provides you 2 major benefits

  • First is fiberglass insulation maintains thermal insulation inside your home year-round.
  • Second, it will protect your house from all types of noise such as traffic noise, construction sites, neighbors’ busy noise, and so on.

Fiberglass insulation is a combination of the medium and high density of glass fiber that can absorb from high to low levels of noise.

Around 50 to 60% of manufacturers use recycled glass to make fiberglass insulation. This is really a great option if you have residential or commercial projects, so you can save a few dollars by using it.


Because it is a little bit cheaper from all of the insulations. But is it really a good soundproofing material?

This is very simple to judge, any type of soundproofing and insulating material you just need its measuring formula.

Am I right?

In Soundproofing and Insulation, we have STC and R-value. Do you know about it? No.

Let’s try to understand a little bit of information about What is STC and R-Value so that you can determine, is fiberglass insulation good for soundproofing your house or not?

What is R-Value

R-value (Resistance value) is some sort of measurement formula that tells how well this material is for thermal insulation. It means, higher the R-Value the better the performance you will get from a material.

The approximately better R-Value is from R-13 to R-38, so if the material is providing this R-value of resistance. Then you don’t need to wander here and there.

For example, if you are living in Russia then you probably need a high R-value of insulation but If the house is in Kuwait so the R-value should be down.

So if you are living in the coldest place then I recommend to you to use a material that provides the best insulating power otherwise you will freeze!.

Because, if the material has a higher R-Value then the flow of heat and sound from walls, calling, and a window will less pass through.

In this way, you can save around 10 to 20% on your electricity bill also. According to the US Department Of Energy electricity consumption will drop down by 10 to 15% of all the US houses if they started insulating their houses.

What is STC

STC (Sound Transmission Class) is a number that tells how the material is well to reduce the soundwaves through the walls, ceiling, window, and door.

If you want a noise-free environment then you should have an STC number above 50. For more on What is STR, NRC, and R Values I strongly suggest reading the exclusive guide which I earlier shared.

Fiberglass Insulation: How It’s Made & Why This Is Important

Fiberglass insulation mainly works in residential houses that’s why its manufactures are using simple thermoset tiny plastic petals.

That provides more flexibility to use it anywhere and this can be fit at any place in your house. Moreover, Its thermal and insulation properties will combine all the things and provide you noise-free and thermal environment.

According to WordPress, the final product from fiberglass doesn’t have any defect of the surface; it means the whole surface is defect-free.

So if you compare it from wool and foam then you will get defeated. Because additionally, this is much heavier and thicker than any other insulation so that fiberglass insulation blocks every soundwave at the outside and thermal at the inside.

Fiberglass needs a large scale of production and that has 3 major levels first one is the collection, cropping, and the last sneezing.

After all these, you will get world-class fiberglass insulation that has the capacity to absorb any type of noise.

But if you are living near a busy traffic place or construction site then you need some extra soundproofing material, if your focus is soundproof only.

Fiberglass Insulation Requirements

Although you can judge your fiberglass insulation according to the above measurements, those are just measurements. How can you calculate those?

Those measurements are related to technical aspects only. But we have some other parameters so you can check your fiberglass.

1. Should be Moisture Resistance

Fiberglass should be moisture resistant. I mean when installing the fiberglass in your house the installer should check first that fiberglass must be fully dried or not.

If the installer finds an area that holds water then it should be dry before anything else.

2. Should be Fire Resistance

Fiberglass insulation does not require any additional fire chemicals treatment because it is made from recycled glass and sand. As you know these materials are naturally non-combustible.

3. Should Have Acoustical Properties

Why do you want fiberglass insulation? For soundproofing and thermal insulation, right?

So fiberglass insulation has the capacity to block and reduce the sound transmission through the walls, ceiling, window, and so on.

4. Should Build From Recycled Materials

Do you know manufacturers using recycled glass since 2000 to build fiberglass insulation? Around 3.6B KG of glass fiber has been recycled from this process since 2000.

This will work better from the newly made fiberglass so you have to ask, is my fiberglass insulation is made from recycled material or not.

So these are requirements of fiberglass insulation so if you are planning to install it then you can check these parameters.

Major Properties in Fiberglass Insulation

As you know fiberglass insulation has amazing thermal and soundproofing quality but how fiberglass gets those, do you know? Let’s understand the major properties that fiberglass insulation has and how you will benefit from them.

  • Fiberglass insulation is more resistant than steel components.
  • Only a single layer of fiberglass insulation will work as an electrical insulator.
  • Fiberglass insulation has naturally non-combustible properties that will also protect your house from fire. 
  • It also comes in tiny petals but this will not rotate in the cavity anymore so this will block more thermal energy inside.
  • If you have any electromagnetic window at your house then fiberglass insulation has dielectric permeability that easily transfers.

Now fiberglass insulation properties finish? No, this is just a trailer, the movie has not started yet.

Types of fiberglass insulation

Which fiberglass insulation is good? I know we have several types of fiberglass insulation but which one is best. Today, allow me, I have selected the 3 best fiberglass insulation that will help you for complete silence and thermal in your house.

1. Batts Fiberglass Insulation

Batts fiberglass insulation is a traditionally made insulation that comes in a tow material. The first one is Rockwool and the second one is fiberglass as well.

So which one is the best fiberglass batts insulation vs Rockwool batts insulation? 

Although both insulations are the best in my opinion, if your focus is only thermal insulation in your house then you definitely go with Rockwool batts insulation.

Or if you want to soundproof your house with thermal quality as well then I suggest you select fiberglass insulation.

Because batts fiberglass insulation creates a heavy vapor barrier inside your house that protects your house from climate change. So in my opinion fiberglass insulation is the best insulation for soundproofing walls.

2. Blow-In Fiberglass Insulation

Blow-in fiberglass insulation is also called loose-fill fiberglass insulation. That is usually made from molten glass and has the capacity to reduce the high level of sound waves.

Because it will easily fit any type of cavity and hole and provides you around R-15 To R-30 per inch of density.

Mainly blow-in fiberglass insulation used in the attic and floor in your house. Because this is the super expending material that can be fit in a very small area. So when the process work is going at your home then you don’t need any large area.

All you need is just a blowing machine to blow out the fiberglass insulation at the surface and you have a choice of how much thick layer you want at your house.

For better insulation and thermal you can add at least 3 layers. Use fiberglass insulation around ductwork and wrap it up so that it will provide proper thermal insulation.

3. Blanket Fiberglass Insulation

Fiberglass insulation also comes in a blanket form that can be usable at your house but this is an expensive way. If you want to use it then you need to pay extra for it.


Because this is the next level of blow in fiberglass insulation. After getting the tiny petals, machines give a shape that looks like a blanket.

That easily fits at the walls ceiling and floors as well. I think this is the better option of blow-in because you will get the flexibility to use it. And you can do it by yourself just put it in your hand moved inside the drywall.

4. Roll Fiberglass Insulation

This is the same as the blanket fiberglass insulation. The roll-fiberglass insulation comes in a bigger size so you can cut it according to your need.

Additionally, this is much thicker than any others so if you are living near a very busy street. Then I recommend you use it in your house attic and floor as well.

How can you manage a blow in fiber mess in your house? Literally, I do like blow-in fiberglass insulation because its small petals will spread in the entire house.

And I can’t do it myself on the other hand rolls, blankets, and batts fiberglass insulation is very easy to install.

Fiberglass Insulation Installation

Fiberglass insulation installation is not too hard but it is not too easy. In most cases, we don’t need any professionals but in some cases, we need them.

Like in blow-in fiber we usually need a professional hand so the works have done well. Now I am covering a step-by-step process of how you can install batts insulation in your house.

This is the most common and very effective insulation. So let’s get into this.

  1. So first you need to take the first batt insulation and unface it into the stud bay. Start at the top and make sure to push up nice and tight. Because if you do very tightly then the R-value goes down and I think you don’t want to do that.
  2. When bringing it down to the bottom then use the knife and cut the extra piece. Make sure to tighten it between the stud so it can provide better insulation.
  3. If you face the electrical box while installing it then do not cut it down. Just split the backside of fiberglass then put it behind the box then slice the above part of the fiberglass. Then curl it inside.
  4. When encountering the air condition pipe then split the fiberglass in the middle and take the first piece and put it behind the pipe. Then put the second piece lay on top of that. Make sure to follow all the above things.
  5. Now, this is the time to seal the window then you can use spray foam and start the top and go slow at the bottom.
  6. Now, you need to take care of the wall. It means the joints from the attic and walls. So cut the square shape of batts fiberglass then push it back inside the joints. Make sure the paper is against the room.
  7. To prevent itchiness and rashes you need to use a 3mil polyurethane vapor barrier and cover the whole wall from it.

Still Confused!. Watch this video. 


Rockwool vs Fiberglass For Sound Absorption: Which One Is Best?

If you want better sound and thermal insulation or if you are confused about which one is best for your house?

Then I recommend you to read this difference between Rockwool and Fiberglass so that you can make a wise decision. 

  • Fiberglass is easier to install than Rockwool.
  • Fiberglass is an inexpensive material than Rockwool.
  • Rockwool is better at absorbing low-frequency sound waves than Fiberglass. 
  • Fiberglass is better to block all the noise from outside.
  • In Fiberglass Batts insulation will not rotate on its sight. 
  • Fiberglass is naturally a better thermal insulator that protects your house from outside climate change.

So this is the fiberglass insulation alternative if you want then you can also check it and other once.

Wrap Up With My Experience of Fiberglass Insulation

I didn’t feel the need to use any type of insulation because I was living in a cemented house. But later changing the house to the wooden materials, I felt the need for the insulations.

Because the weather and many types of noise disturb my silence. So I started researching on the Internet and found Fiberglass insulation best for my house.

Then I ordered it and called the professional because I didn’t have time to install it. In a day they installed blow-in fiberglass at the attic and floor and batt insulation at the walls and joints.

The major problem I have faced is the itchiness so again call the professional and ask them to give me advice to use polyurethane plastic film above the insulation. 

After all the things have been done I really feel the big change in the noise and thermal insulation. Now, I can easily work in my house and spend quality time with my family as well. Literally, my electricity bill goes down by 15%, I was shocked!. 

That’s why I thought this experience needs to be online so that anyone can understand fiberglass insulation. And I think I have covered all the necessary information about it.

So this is my experience. What is your experience with it? Have you already installed fiberglass insulation or you are planning it? Share at the comment section so the people understand.

FAQ: Fiberglass Insulation For Soundproofing

I have seen many people have many questions about fiberglass insulation. So I have tried my best to give appropriate information about it. So if you have your’s one then just comment down below I will answer as soon as possible. 

Q1. Is fiberglass insulation dangerous?

Ans: Literally, I have seen many people discussing don’t using fiberglass because it will give you cancer. Is it***? I don’t say anything.

According to my opinion and experience, I didn’t face any health issues yet. But I suggest you just ignore them because almost 25% of US houses already use Fiberglass, so how dangerous is it?

But I suggest you use plastic film and cover the whole walls after using batts insulation. That will plus your safety.

Q2. How much does it cost to insulate a 2000 sq ft house?

Ans: When installing the fiberglass insulation it depends on what form of fiberglass you select for your house. But on average it will cost you around 0.38 to 1.94$ per sq ft. So for 2000 sq ft, you need to pay 760 to 3880$. 

Thanks for reading!. Be safe and have a good day. 

Hey, I am Kirtish Vyas a YouTuber and believer in making life peaceful, a couple of years back I started soundproofing my house, bedroom, studio, and Car to reduce the unwanted noise, and the same experience I am sharing on SoundProofidea. Read More