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Roxul vs Fiberglass Insulation for Soundproofing Purposes

Silent Home Hub Roxul vs Fiberglass Insulation for Soundproofing

Noise is like a bad backache that’s nearly impossible to get rid of — UNTIL we’re given the options to reduce their presence.

Now, what exactly are these options? There are two ways you can SOUNDPROOF EFFECTIVELY: with Fiberglass or Roxul.

Both rockwool insulation and fiberglass have their own value in soundproofing noise. If you’re confused about which one to choose, it’s time to read our guide below.

For this Roxul and Fiberglass insulation for soundproofing comparison, we’re going to count their stand-out features and explain everything you need to know about them as insulation materials!

Table of Contents

What is Roxul or Rockwool Soundproofing?

Roxul is a company and commonly known for its product: STONE WOOL. They manufacture stone wool insulation for all kinds of places — a classroom, music studio, media rooms, or a home office.

You may know rockwool insulation as mineral insulation, too. Rockwool insulation is made possible by spinning molten rock and minerals together. The end result is wool-like insulation for your rooms!

We can measure how much rockwool can absorb noise with the Noise Reduction Coefficient or NRC.

With NRC, the HIGHER the rating, the MORE you’ll find efficient sound absorption. The rating is between 0 and 1.

Due to rockwool’s dense and porous material, its NRC RATING IS AT .95!

What is Fiberglass Soundproofing?

You may know fiberglass as one of the most versatile, lightweight soundproofing methods out there. You can use fiberglass for a lot of noise-improving purposes.

True to its name, fiberglass contains tiny particles of glass fibers woven with fiber-reinforced plastic. Fiberglass insulation absorbs sound waves. It blocks them, too, but it’s less efficient with that purpose.

GREAT NEWS: Fiberglass has an NRC rating of .90 – .95!

With that in mind, fiberglass is better for a home office, but not for corporate offices or studios. We’ll go more in-depth with both of these product’s features below.

Face-Off Features: Roxul vs. Fiberglass Insulation for Soundproofing

Roxul mineral wool and fiberglass soundproofing share SIMILAR FEATURES when it comes to noise and sound insulation.

It’s time to find out which soundproofing insulation wins for each feature. Follow the five rounds below!

Round 1: NRC Rating

The NRC rating or Noise Reduction Coefficient rating measures how well a product can absorb noise. We’ve already mentioned this before, so we’re sure you already know the winner! But let’s dive into more detail.

Fiberglass Insulation

Fiberglass has an NRC rating of .90 -.95.


Some manufacturers create fiberglass models that RANGE FROM .50 to 1.15!

Imagine that!

NRC ratings are between 0 and 1. You can’t go under 0 – there’s no perfectly reflective material.

But as you can see above, you can go over 1, making a perfect noise absorbent material even more effective. Owens-Corning products may fluctuate with these ratings here and there.

As long as the rating is .75 or higher, YOU CAN TRUST the material to absorb sound efficiently!

Roxul/Rockwool Insulation

At first, we found rockwool’s ratings at .95. However, it has more up their sleeve.

Some of Roxul’s products — from Safe n Sound to acoustic soundproofing — go up to a rating of 1.05! You can trust Roxul’s sound absorption ability no matter what you buy.

Winner: The numbers don’t lie. Fiberglass can absorb sound waves better!

Round 2: R-Value

If the NRC rating can measure how much thermal insulation can absorb sound, the R-value measures how much it can resist it.

In addition to noise resistance, this value can also measure how much it can resist heat and how heat transfer will likely take place.

JUST REMEMBER: The higher the R-value, the more resistant the material is.

Fiberglass Insulation

You can install fiberglass as fiberglass batts or as loose cellulose. There are two different R-values for each.

The fiberglass batts material has an R-value rating range of 2.2 – 2.9.

Meanwhile, the loose-fill type material ranges from 2.9 to 3.8. Like the rating above, Owens-Corning products can fluctuate with how much sound transfer the matter can resist.

Roxul/Rockwool Insulation

Roxul has a much higher rating than we expected! Their R-value rating starts at 3.3 – 3.7. This sound-blocking choice has a higher density, so its thickness keeps absorption at its best.

Winner: It’s tricky as they have almost the same values, but we’ll go with Roxul for this round. Their starting range has a much higher resistance compared to fiberglass.

Round 3: Versatility

More often than not, sound insulation also doubles as fireproofing and protection from the elements. So, it’s time to ask: what else can your chosen insulation do for you?

Fiberglass Soundproofing

Fiberglass, whether loose or in batts, are perfect for residential and commercial buildings.

While fiberglass is far from flammable, some of the products used in the installation process might be. Paper and foil backings can catch fire, too! It might be best to be on the lookout when you install fiberglass into your rooms.

However, fiberglass can RESIST mildew and moisture. You don’t have to worry about your interior walls rotting out.

It also acts as a way to control the temperature within your rooms. It INCREASES heat energy efficiency by slowing down both hot and cold air gaps. You get improved air quality, too!

Roxul/Rockwool Insulation

Roxul offers a range of possible installations for your place. Whether you need your interior walls, ceilings, or floors soundproofed, Roxul has you covered.

Roxul does acoustic wall insulation for both interior and exterior walls. That way, you can prevent sound from coming in as much as it comes out. Facades, partitions, and party walls are also no concern.

Even your floor and ceiling joist can benefit from sound attenuation, too. Anything’s possible with Roxul in control.

While Roxul is fireproof, it’s also water-repellent. You can resist elements along with sounds. As a result, the soundproofed wall isn’t susceptible to rotting, mildew, or fungi.

Winner: It’s a tie. Fiberglass is great for moisture, temperature, and airflow. However, Roxul works well for every kind of insulation possible! Plus, it’s also fireproof and water-repellent.

Round 4: STC Rating 

The STC or sound transmission class rating measures how well your choice of insulation reduces sound from transmitting.

Like all the ratings we’ve discussed above, the higher the rating, the better the insulation is.

Fiberglass Soundproofing 

Fiberglass insulations’ STC rating is at 36.

While the rating isn’t that high to block out noise, the resulting sound is still intelligible.

What does this mean?

You’ll still get some noise through your walls, but it won’t be as disturbing. You can choose density levels for more padding when needed.

Rockwool Insulation

Roxul insulation — especially when installed as batts — is definitely higher! Their STC rating is at 50. With this rating, you have MORE PRIVACY in your rooms.

Loud speech is hardly audible, and the wool insulation will definitely muffle the sound of musical instruments.

Winner: There’s no contest. According to the ratings, Roxul reduces the most sound!

Round 5: Durability

Remember: soundproofing is an investment. We have to ask ourselves about the cost-efficiency of what we get.

For fiberglass and Roxul insulation, we have to take durability into account. How long can both products last? After all, you want the most sound attenuation for your money.

Fiberglass Soundproofing

There are no current measurements on how long fiberglass will last. However, it’s not likely to decompose. We can just trust that this sound-proofing method is installed correctly.

Over time, there is a drawback: fiberglass can compress and reduce how many sound waves it can block.

Rockwool Insulation

Roxul claims to last for the rest of the building’s lifetime. Rock wool shouldn’t decay as it only has inorganic soundproofing materials.

In the end, like fiberglass, you can only trust people to install it properly into floor joists, walls, the ceiling — or wherever you prefer to place your soundproof insulation.

Winner: Once again, it’s a tie! Both of them aren’t likely to decay, so you can trust them to last for a lifetime. Investing in either form of sound blocking is going to last you for a long while.

Overall Winner

Were you keeping track of how the two sound blocking choices faced one another? There’s a definite OVERALL WINNER: Roxul!

Despite the two ties, Roxul wins the sound transmission ratings and R-values.

Of course, these ratings won’t guarantee perfect sound blockage. Still, they’re an excellent standard to rely on when choosing your sound blocking products.

Stand-Out Features

Roxul or Mineral Wool Insulation is More Fireproof

Fiberglass isn’t flammable, so you don’t have to worry about spreading fire if you choose fiberglass. However, if you want extra protection for your house, you may want to go with mineral wool.

Fiberglass METLS at around 600 degrees Celsius (1100 degrees Fahrenheit). Meanwhile, Roxul has more fire resistance. Its melting point is at 1000 degrees Celsius, or 1800 degrees Fahrenheit.

If you live somewhere where fires are a common occurrence or just want that extra layer of protection, go for stone wool.

Both Fiberglass and Rock Wool are Eco-Friendly — the Latter with a Cost

Fiberglass is a sustainable sound-blocking solution due to its primary sand component. It’s energy-efficient, and best of all, it’s MEANT TO LAST.

Yes — 110% guaranteed to last.

No matter what type you have it brought in — in batts or as loose filling — you can make sure it stays in your wall, floor, or ceiling for a long time.

And on the other side of the ring…

Rockwool is bent on making sure its sustainability is top-notch. Stone wool is energy-efficient!

However, how it comes to be a sound-blocking choice isn’t the best environmentally-friendly solution. It’s also potentially harmful to your health.

While the components are naturally occurring in the environment, stone wool itself is an unnatural hybrid.

Sure, it won’t decompose or degrade. But the moment it leaves your ceiling or wall, it’ll end up in a landfill.

It’ll block sound waves effectively, but it’ll take a long time before it decays.

Some Considerations

Before you employ either soundproofing method, there are some considerations you need to take into account.


You can use batts or continuous rolls for both soundproofing solutions.

Batts have different widths and thicknesses, plus you can easily cut them up to fit into open wall cavities. Joists can accommodate these wall cavities well.

Remember to choose the right R-values for your place. Density can vary, too. Batts and rolls can come in different ratings!

You want to consider how to adequately soundproof if your wall has studs. Wood stud walls are easy enough to insulate when it’s already existing. You just fill up the cavity.

However, you may be considering building brand new interior stud walls. If that’s the case, make sure you UPGRADE THE WALL STUDS you’ve got!

Isolate your frame, make it thicker, and get plasterboard with a higher mass. Thickness and mass count into a much higher density for your place!

If you’re dealing with wall soundproofing, whether with studs or not, you want to make the most out of it.

Added Sound Attenuation

If you want more sound-blocking for your place, you can control what you want to add.

While you can fill traditional drywall panels with sound-blocking solutions immediately, you can look into building soundproof drywall panels, too.

Products like QuietRock are an EXCELLENT OPTION if you want soundproofed drywall for your place.

If you build drywall with added insulation at the proper density, soundproofing is much more effective!

Still need more soundproofing? Use Green Glue. Green Glue isn’t actually glue, but a compound you can spread all over your drywall.

You can decouple surfaces by using staggered studs. Insulate the cavity with high-density mass!

If all else fails, you can resort to cheaper, DIY soundproofing solutions.

You can add window films, soundproof curtains, and DIY acoustic panels. Even just getting furniture or rearranging what you already own can help control the transfer of sound!


BEFORE you choose a sound-blocking solution, money comes into play. Identify where you want sound transfer reduced — is it up at the attic or ceiling? Do you just want your wall soundproofed?

Then, take into account what already exists in your place as sound-blocking: Maybe you already have a soundproofed drywall. Maybe you have thick curtains, rugs, or plush upholstery where sound waves can bounce off of already!

You also have to choose which professional service will do the job to control sound in your place.

Prices may vary, but overall, you need to decide what’s best for your needs. Make sure you don’t break the bank!

The Verdict

Our winner is Roxul! It won our face-off with the MOST sound absorption and reduction. It’s pretty versatile, durable, and can resist fire and moisture as well. In the end, you end up benefitting more from it.

However, it doesn’t come without any drawbacks, like many soundproofing materials do. It’s not the most eco-friendly option, so make sure you’re investment is for the long-term.


Couple cuddling on a couch

We may think that soundproofing is a luxury, but noise can easily encroach upon your comfort and privacy. Even if you’re not running a music studio or in your office, you still need to block sound waves from coming in and out.

It can disturb you from the most mundane of chores, wake your children up, and even agitate your pets. Overall, in our opinion, soundproofing can increase your quality of life.

While Roxul is the winner, you may have different considerations and choose another form of sound attenuation. You might want to choose added soundproofing solutions with more thickness and density.

Just consider this as a guide and factor in your lifestyle and needs to the kind of thermal insulation you need.

We hope this helped! Are you ready to soundproof your house from the walls to the ceilings?


July 12, 2021 – updated article links, removed product links

June 24, 2021 – fixed article formatting, updated article links, optimized content

About the Author


Andrea has always been bombarded by the hustle and bustle outside her home. Living in the city doesn’t get any quieter. The never ending noise from construction, traffic, and dogs barking on the streets day in and day out drove Andrea to a breaking point.

For 3 years, Andrea committed herself to studying DIY hacks, performing soundproofing experiments, and installing noise-free solutions. Now, she lives a quiet life free of the stress from noisy environments.

She hopes to share this knowledge so that others don’t have to endure the noise reigning in their ears and live a peaceful, stress-free life.