Best Insulation For Soundproofing

by Jennifer Porterfield | Last Updated: November 1, 2021
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Insulation isn’t just important to keep your home warm in the cold winter months, it can also help in soundproofing your home.

Best Insulation For Soundproofing

If you play a lot of music, have a large loud family, or just in general make a lot of noise, then soundproofing your home is the best way to avoid annoying your neighbors.

It’s important to know that there is usually a difference between insulating products and soundproofing materials.

Usually, the soundproofing qualities of the insulation are not a priority for most manufacturers, as they instead want to focus their product on keeping your home warm. 

Saying that there are a few standout products that can keep the cold out and the sound in, so let’s take a look at the best insulation for soundproofing you can buy.

And just to help you out even more you can take a look at the buyer’s guide at the end to learn about the different types of insulation normally found in homes, so you can choose the best option for you. 

Roxul Rockwool 80 Acoustic Mineral Wool Insulation

Rockwool Acoustic Mineral Wool Insulation 60-6lbs per sheet...

Roxul is no stranger to the soundproofing world, having become most well known for their acoustic fabric panels that can be found in recording studios and homes worldwide.

This insulation is made out of a similar material that has been modified to also work as insulation, so you should have no trouble in keeping the sound in your home. 

This is a batt insulation product, with the panels coming in a 48 by 24-inch size no matter what density you choose. This size is ideal for filling the spaces between wall studs or ceiling and floor joints.

If you don’t want to install this as an in-wall insulation though, the mineral wool can also be used as acoustic panels on its own by simply sticking them to your walls.

The panels come in a range of densities ranging from 1 inch to 4-inch versions. While you may think that the thinner the panel the less effective it will be at noise reduction, this is not the case with the Rockwell insulation.

This insulation has a noise reduction coefficient (NRC) of  0.8, meaning that it will stop 80% of airborne frequencies. 

How well the insulation works at reducing noise will depend on the density that you buy, whether that be the Rockwell 40, 60, or 80, but it will still be able to reduce an impressive amount of noise no matter what size you get. 

Like a lot of soundproofing material, Rockwool insulation is better at absorbing high frequencies than lower ones, which is something you may want to consider before you buy.

In the 125 Hertz (Hz) range, its NRC score drops slightly to 0.7, but getting a bigger insulation panel, like the 4-inch Rockwool 80, will raise this score to 1.03 NRC. 

While this is one of the best soundproofing materials on the market, it is also hydrophobic meaning that it won’t hold moisture and get damp, and is also made out of a Class A fire-resistant material.

This product guarantees to keep sound within your home and makes sure you’re also kept safe and warm by the insulation. 

Pros

  • Insulation levels don’t change with time/age – a lot of insulations lose their value and their ability to retain heat over time, but this does not seem to be the case with Rockwool insulation. Even after years, your home should still be kept warm by this insulation. 
  • Can insulate from outside noise as well as keep sound in – If you live on a busy street then this insulation can keep the sounds of the outside environment out of your home, making your life a lot more peaceful.

Cons

  • High cost – unfortunately, if you want a premium product then you will have to pay a premium price. This type of insulation usually costs around 10% than fiberglass insulation, which is one of the most common types found in homes. However other types of insulation don’t work as well in soundproofing your home, so if that’s the factor you are focused on most then this will still be the best option for you. 
Rockwool Acoustic Mineral Wool Insulation 60-6lbs per sheet...
89 Reviews
Rockwool Acoustic Mineral Wool Insulation 60-6lbs per sheet...
  • Mineral Wool Insulation in 6 pounds per unit density.
  • Great as Acoustic insulation or as a soundproofing material
  • Cost effective and Very High NRC Rating, better than Owens Corning 703
  • Water repelling - hydrophobic- Class A fire rating
  • Rigid Boards, perfect for making acoustic panels and bass traps

Auralex Acoustical Mineral Fiber Insulation

Auralex 2MF24 2 Mineral Fiber Insulation; 6-2'x4'x2 Panels...

Auralex is another company that is no stranger to producing high-quality soundproofing products. They make some of the best bass traps, sound diffusers, and resilient channels on the market, so it’s no surprise that they have branched out into insulation. 

Like the previous product, this is also batt insulation that comes in panels. The panels have the same dimensions of 48 by 24 inches, so they’re perfect for fitting between wall studs or joints. 

Depending on how thick the panels are will impact how much square footage of wall/floor space you can cover with a single pack of the material.

So if you buy the 2-inch version you will get 6-panels that covers a total area of 48 square feet. If you get thicker panels then these come in packs of three, which will be enough to cover 24 square feet. 

Like most soundproofing insulations, this one will block higher frequencies better than low ones. Still, as this insulation is made of high-quality mineral fiber it has an NRC of 1, meaning that it will block 100% of airborne frequencies.

The thicker the insulation the better it is at insulating from sound as well, so at 4 inches thick, this number increases to 1.05. 

As mineral fibers are fire-resistant, this is another insulation that has earned a Class A fire-resistant rating.

Also, according to the company it offers better sound insulation and acoustic absorption than standard fiberglass, so you don’t have to worry about sounds escaping your home. 

Pros

  • Can fit easily in your walls and floors – The size of the panels means that cutting them down to size to fit in spaces is very unlikely
  • Very high NRC rating – it can block 100% of airborne frequencies, meaning that outside noise won’t enter your home, and your in-home noise won’t escape outside

Cons

  • Unsure of how well it keeps heat in – this insulation definitely focuses more on the soundproofing benefits over the heating benefits, so we are unsure about how well it will keep heat in your home. Saying that mineral fiber insulation is a very good product for insulation and is used in many peoples homes so it most likely works well enough
Auralex 2MF24 2 Mineral Fiber Insulation; 6-2'x4'x2 Panels...
151 Reviews
Auralex 2MF24 2 Mineral Fiber Insulation; 6-2'x4'x2 Panels...
  • Specifically designed insulation for acoustical usage
  • Yields better bass trapping, overall absorption, thermal characteristics and transmission loss (isolation) than other insulation products.
  • Mineral Fiber insulation is considerably more dense than standard insulation
  • For best sound isolation, Auralex recommends incorporating the following products into your room construction in the options shown above

Acoustimac ECO Cellulose Acoustic Insulation

Acoustimac Acoustic Insulation ECO CELLULOSE - 4lbs per unit...

As usual for this list this insulation comes in panel form that is 48 by 24 inches, and as standard are 2 inches thick. While they weigh about a pound each, they have a density of around 4 pounds per cubic foot. 

The material performs very well in frequency ranges between 500-4000Hz, but once again shows signs of dipping in efficiency once you get to the lower sound ranges.

At the high end of the scale, you will be getting an NRC rating of 1.06-1.18, but once you get to the 125-200Hz range this drops to an NRC rating of 0.39-0.51.

Despite this, it’s still some of the most impressive performance ratings for soundproofing insulation. 

This insulation is not only perfect for people who will be making a lot of noise, but also for the more ECO-conscious customer.

Cellulose fiber is made out of renewable and recyclable or reduced materials, with the manufacturing process also resulting in almost zero waste. 

The Acoustimac ECO insulation is made from a blend of cellulose, paper, and cotton, so it won’t be difficult to trim to size to fit into tight spaces if you need to.

Also when you are cutting it doesn’t present the same dangers that fiberglass insulation does, as the materials in these insulations can irritate your eyes and lungs.

The worst you will get with this cellulose material is that you may inhale some dust, but it is harmless. 

Given that it’s made out of flammable materials, you may be concerned about installing it in your home.  But you really have nothing to worry about as the insulation is treated with fire resistant chemicals and has earned a Class A fire rating.

Pros 

  • One of the best insulations for the environment – as it’s made of natural materials and the manufacturing process makes almost zero waste, this is one of the best insulations for the ECO conscious
  • Very good at reducing noise – despite being made out of recycled materials, this is still one of the best insulations out there for reducing the noise coming from outside, as well as preventing noise from your home making its way outside

Cons

  • Over time it will become less effective at keeping the heat in – this is an issue with almost all insulations, as over time they break down and become less effective. Still, this is a process that takes over 20 years sometimes, so you won’t have to worry for a long time about this
Acoustimac Acoustic Insulation ECO CELLULOSE - 4lbs per unit...
22 Reviews
Acoustimac Acoustic Insulation ECO CELLULOSE - 4lbs per unit...
  • Shipped by the Case
  • Revolutionary Acoustical Material
  • Made of 100% Recycled Materials
  • People Friendly NO VOC'S

Foam It Green 602 Closed Cell Spray Foam Insulation Kit

Foam It Green 602 Closed Cell Spray Foam Insulation Kit

Foam insulation is one of the most convenient and easy to install types of insulation you get, as it’s able to seal and insulate any area in just seconds.

It works by expanding rapidly once you have sprayed it onto a surface, so by applying around an inch of this product wherever you need it, you could cover a huge area of around 602 square feet. 

When buying this product you will get everything you will need to apply this product correctly and safely. This includes:

  • Pressurized application canisters for foam delivery
  • 15-foot hose with an application gun
  • 10 nozzles
  • 3 fan spray tips 
  • Isocyanate-resistant gloves 
  • Tyvek suit

The foam is made by mixing the green and yellow components, with a light green color appearing when it is all mixed correctly. 

The foam is classified as a Class I E-84 fire retardant, so not as high as the other insulations on this list but still enough to protect you and your home.

It is also antimicrobial, so you won’t have to worry about any mold growth once you close up the surface you’re insinuating. 

While this insulation doesn’t give much of an indicator about how well it works at soundproofing your home, as it can be used to fill up any small cracks or holes that allow sound to escape, we can conclude that it works well at keeping sound as well as heat inside your home. 

Pros 

  • Super easy to apply– one of the biggest appeals of spray foam insulation is that it’s easy to apply as you just spray it on the surface and the foam does the rest of the work for you
  • Creates an air-tight seal – This keeps heat and sound in your home 

Cons

  • High installation costs – given how much equipment you need to install this insulation, it can be quite a pricy purchase
Foam It Green 602 Closed Cell Spray Foam Insulation Kit
151 Reviews
Foam It Green 602 Closed Cell Spray Foam Insulation Kit
  • Quickly Seals Out Air & Insulates
  • 17 Free Extras with Orders Over $250
  • Light Green Foam Reduces Waste
  • Appr. 602 square feet at 1 inch thick of cured foam
  • 24/7 Customer Support

Owens Corning 703 Fiberglass Board

Owens Corning 703 Fiberglass Board 2' QTY 6

Going back to the batt insulation, this one once again comes in panels of 24 by 48 inches, and is usually 2 inches thick, though you can get them in a range of thickness. These panels come in a pack of 6 so you will be able to cover a huge area. 

This product is made of inorganic glass fibers and the panels have a thermosetting resin binder. This can make them either flexible or rigid depending on how they are treated and how you want to use them. 

This insulation has an average NRC of 1 across all frequency ranges, though it seems to work best in the 500-2000 Hz range.

Still, it is still able to score over 0.86 NRC around 250 Hz which is quite impressive. At its lowest though, when faced with 125 Hz frequencies, it has an NRC of just 0.17. 

While fiberglass insulation is somewhat fire-resistant after being treated with chemicals, this insulation often comes with either a foil (FRK) or vapor barrier (ASJ) facing, which helps improve its fire resistance. 

Pros

  • The cheapest form of insulation – this makes it the most popular choice to be installed in homes. It is also one of the most effective at keeping the heat in
  • Includes vapor barrier  – this ensures that the insulation or the walls around it won’t become damp or moldy

Cons

  • Unsure of how well it soundproofs – fiberglass insulation, while very popular, can decrease in effectiveness over time, meaning that it won’t work as well in heating or soundproofing your home. 
Owens Corning 703 Fiberglass Board 2' QTY 6
83 Reviews
Owens Corning 703 Fiberglass Board 2" QTY 6
  • 703 is lightweight, resilient, easy to handle and fabricate on the job site
  • Resists damage and maintains structural integrity and efficiency
  • Reduces heat transfer, lowering operating costs
  • Efficiently reduces sound transmission

Buyers Guide

Now that you know of the best soundproofing insulations you can buy, let’s take a deeper look at the different types of insulations we have mentioned here so you can make the right decision for you and your home. 

Batt Insulation

This is a type of blanket insulation that usually comes in rolls or panels. They are usually as wide as the average space between the wooden studs in your walls/floor joints/ceiling beams, and come in a variety of thicknesses. 

You need to consider the base material of the insulation before you buy it, as this will affect how well it can insulate and soundproof your home.

The most common type of batt insulation is fiberglass, which is durable and fire-resistant. You need to wear protective gear when installing it to stop the particles from it getting in your eyes or airways. 

Foam Spray Insulation

Polyurethane foam spray is perfect for filling in any oddly shaped holes in your walls. The foam expands to fill the space and then hardens quickly so you don’t have to worry about waiting for it to dry.

While it may seem very convenient there are some downsides to this insulation. The main one is that it doesn’t have any kind of built-in thermal barrier, so it may not be as effective in heating your home as other products.

It is also not very fire resistant unless it has been treated with chemicals first. 

Saying that if you are only using it to fill up small spaces then this is a much better and safer option for you than cutting large rolls or panels of insualtion. 

Frequently Asked Questions

What R-value Rating Is Best For Soundproofing?

An R-value rating is the number that tells you how good a material is at resisting the flow of heat. The higher the number the better it is at keeping heat within your home.

When soundproofing your home, the best option is to use R-13 insulation in the walls and R-19 insulation in the ceilings. This is the best level of insulation to keep sound as well as heat in your home. 

Is Styrofoam A Good Sound Insulator?

While styrofoam can dampen or cancel out light noise on its own, it works a lot better when paired with denser materials.

It is however a good insulator and shock absorber on its own, but this is not enough to keep a lot of the sounds in your home.