Is Attic Insulation Soundproof?

Most people think about insulation as a way to regulate temperatures and keep energy costs as low as possible. While this is the primary function of any kind of insulation, some offer generous soundproofing capabilities to keep your home protected from noises both inside and out.

So, is attic insulation soundproof? It can be.

The quality of soundproofing will depend on several factors, including the type of sound you are dealing with and on the kind of insulation installation youโ€™re looking for. While budget and energy needs should always come first when choosing insulation, it never hurts to be aware of the added benefits of getting your attic insulated.

If youโ€™re looking to create a highly regulated acoustic environment for music production, youโ€™ll probably want to look into professional soundproofing panels made of wood, fabric, or foam. If you came here curious about the soundproofing benefits of insulating your attic, then read on to see what our guide has to offer.

Types of Sound

Before you go shopping for soundproof attic insulation, itโ€™s important to understand the types of noise that can affect your home.

  • Airborne โ€“ Airborne sound is characterized by its ability to transmit through air and structures using sound waves. Typical examples of airborne sound around the home include conversations carried on outdoors, barking dogs, traffic, and car radios. In attics, airborne sound could take the form of a noisy fan or HVAC unit. While it may be impossible to control these kinds of external sounds, it is possible to use insulation to your advantage by dampening and even absorbing them altogether.
  • Structure-borne sound โ€“ In the home, this is typically characterized by the impact of an object, person, or pet on the structures that support your environment. For example, your child bounces a ball on the floor upstairs, your dog knocks something over in the next room over, or your downstairs neighbor is having work done on the ceiling. These structure-borne sounds can be particularly annoying as they tend to cause vibrations throughout the building. Regardless, their severity can be lessened with the help of quality insulation.

What Is a Noise Reduction Coefficient?

When it comes to sound reduction, the quality of a material is measured by its noise reduction coefficient (NRC).1 NRC is determined on a scale of 0 to 1, 1 meaning that the material in question absorbs all sound. If your insulation has been measured at .75 NRC, that means it absorbs 75% of the soundwaves it comes into contact with.

Commonly used in acoustics, NRC can also measure the soundproofing capabilities of insulation. While universally measured in R-value, a measure combining the type of material with its density and thickness, insulation can actually offer soundproofing with high NRC levels as well.2

Soundproofing Quality of Common Insulators

Common insulation materials tend to offer two types of soundproofing. Absorption, typical of porous materials, allows sound to pass into the insulation while converting its energy into heat through friction. Dampening, typical of denser materials, acts to absorb the shock of soundwaves and transfers those vibrations into heat.

The following insulators work to absorb and dampen sound while keeping your atticโ€™s temperature regulated and your home energy costs down:

  • Fiberglass โ€“ Made from a blend of spun plastic and glass fibers, fiberglass is a cost-effective and reliable way to insulate your home. As if this werenโ€™t already enough, fiberglass insulation also comes with an NRC rating of 0.95-1 depending on the thickness of the installation.3
    Mineral Wool โ€“ Made from a blend of fibers spun from superheated igneous rocks like basalt and silica, mineral wool or rock wool is particularly adept and uses its density and porosity to absorb both kinds of sound. While an excellent choice for thermal insulation, mineral wool is both significantly more expensive than fiberglass and offers a nearly identical NRC rating of 0.95-1.05.4
  • Cotton โ€“ Also known as denim insulation, this insulator is made from recycled cotton and typically comes in sheets or panels. 10-15% more expensive than fiberglass, cotton insulation offers competitive NRC levels and is particularly good at absorbing high-frequency sounds.
  • Cellulose โ€“ Made from recycled newspaper shreds, cellulose or blow-in insulation is the cheapest insulator on the market. Depending on the quality of installation (cellulose tends to settle significantly) this insulator can reach 0.8 NRC for your soundproofing needs.5
  • Spray Foam โ€“ Last but not least, this expensive insulator goes from liquid to foam by expanding over 50 times its original volume once sprayed into place. Spray foam is offered in two variations: closed-cell and open-cell. The latter, which is low density, actually offers better soundproofing by filling more open spaces and absorbing more structure-borne sound. As stated above, however, it is by far the most expensive type of insulation on the market and may not quite meet your soundproofing needs with an upper limit of NRC 0.7.6

Control Your Soundscape with Attic Construction

At Attic Construction, we draw on over a decade of experience in attic cleaning, removal of different types of mold, insulation removal, locating rodent entry points and more, to provide the best service possible to our clients in San Diego, Orange County, and Phoenix. However you choose to soundproof your home, attic insulation can offer added protection while serving all of your energy needs.


  1. Audimute. NRC Ratings: What is a Noise Reduction Coefficient?ย 
  2. U.S. Department of Energy. How Insulation Works.ย 
  3. Better Soundproofing. Is Fiberglass Insulation Good for Soundproofing?ย 
  4. Snoring Source. Soundproofing Insulation Explained: Which Material is Best?,in%20the%200.8%2D0.9%20range.ย 
  5. Cellulose Insulation Manufacturers Association. Cellulose Insulation Provides Sound Control.ย 
  6. Tiger Foam Insulation. Open Cell Spray Foam.ย