When it comes to soundproofing and noise reduction, choosing the right insulation material is crucial. Two of the most commonly used materials for sound insulation are fiberglass and rockwool (also known as mineral wool). Both materials have their advantages and limitations in reducing sound transmission, but understanding their differences can help you make an informed decision. In this blog, we’ll compare fiberglass and rockwool for soundproofing applications.

1. Soundproofing Effectiveness

• Fiberglass: Fiberglass insulation is made from fine strands of glass and is typically less dense compared to rockwool. While it does provide some level of soundproofing, it is generally not as effective at blocking sound transmission as rockwool. Fiberglass is more suitable for general insulation rather than heavy-duty soundproofing applications. It works better at absorbing mid to high-frequency sounds but may not be as effective at blocking low-frequency sounds.
• Rockwool: Rockwool is denser and more fibrous than fiberglass, which makes it significantly better at soundproofing. Its dense composition allows it to absorb sound more effectively, especially low-frequency noises. Rockwool is highly effective in applications where you need to block or reduce both airborne sound and impact noise, making it ideal for soundproofing walls, ceilings, and floors. It is often used in home theaters, music studios, offices, and industrial applications.

2. Density and Structure

• Fiberglass: Fiberglass insulation is typically lighter and less dense than rockwool. While it helps in reducing the transmission of sound waves to some extent, it does not absorb sound as effectively as rockwool. The porous nature of fiberglass helps in absorbing sound to a certain degree, but it’s not the most ideal material for rooms where noise control is critical.
• Rockwool: Rockwool insulation, on the other hand, is much denser, which gives it superior sound absorption qualities. Its fibrous structure traps sound waves more effectively, reducing the amount of sound that passes through walls or ceilings. The greater density of rockwool helps prevent sound from penetrating from one room to another, making it a preferred choice for high-performance soundproofing.

3. Frequency Range and Acoustic Performance

• Fiberglass: Fiberglass is more effective at absorbing mid and high-frequency sounds, such as voices, machinery hums, or air conditioning units. However, it is less effective at reducing low-frequency sounds like bass-heavy music or traffic noise. While fiberglass will reduce general sound levels, it might not perform well in environments where low-frequency noise needs to be minimized.
• Rockwool: Rockwool excels at absorbing both low and high-frequency sounds. Its dense structure makes it more effective at preventing low-frequency noise, such as bass or impact noise (e.g., footsteps, furniture moving). This makes it an ideal choice for areas where noise from machinery, industrial equipment, or heavy traffic is a concern.

4. Fire Resistance

• Fiberglass: Fiberglass insulation is naturally fire-resistant since it is made from glass. It can withstand temperatures up to 500°C (932°F), making it a safe option for many insulation applications. However, it does not provide as much fireproofing as rockwool in more extreme conditions.
• Rockwool: Rockwool insulation is highly fire-resistant and can withstand temperatures of over 1,000°C (1,832°F). This makes it an excellent choice for soundproofing in fire-rated applications. It not only provides effective soundproofing but also acts as a fire barrier, preventing the spread of fire in buildings.

5. Moisture Resistance

• Fiberglass: Fiberglass insulation can absorb moisture, which can compromise its soundproofing performance. If exposed to high humidity or water, fiberglass can lose its ability to absorb sound and may encourage the growth of mold or mildew.
• Rockwool: One of the key advantages of rockwool is its moisture resistance. It does not absorb water easily, and even in damp environments, it maintains its soundproofing and thermal insulation properties. This makes it ideal for use in areas with high moisture levels, such as basements or bathrooms.

6. Health and Safety

• Fiberglass: Fiberglass insulation can irritate the skin, eyes, and respiratory system due to the tiny glass fibers it contains. It’s important to wear protective clothing, gloves, goggles, and a mask when handling fiberglass to avoid irritation.
• Rockwool: Rockwool insulation, while generally safe to handle, can cause skin irritation and may release airborne fibers during installation. However, it’s typically less irritating than fiberglass. It’s still important to wear protective gear when handling rockwool to minimize exposure to the fibers.

7. Cost

• Fiberglass: Fiberglass insulation is typically more affordable than rockwool. It is a widely available and budget-friendly option for general insulation needs, including basic soundproofing in residential and commercial settings.
• Rockwool: Rockwool is generally more expensive than fiberglass due to its superior soundproofing and fire-resistant properties. However, if you need high-performance sound insulation or are dealing with fire-sensitive environments, the investment in rockwool may be worth it.

8. Environmental Impact

• Fiberglass: Fiberglass insulation is made from recycled glass, which reduces its environmental impact. However, the production of fiberglass can be energy-intensive, and it is not always recyclable at the end of its lifespan.
• Rockwool: Rockwool can be made from recycled slag (a byproduct of steel production) and recycled glass. It is generally considered an eco-friendly option, although its manufacturing process can be energy-intensive. Like fiberglass, rockwool may not be recyclable in all regions.

Conclusion: Which Is Better for Sound Insulation — Fiberglass or Rockwool?

When comparing fiberglass and rockwool for soundproofing, rockwool is the clear winner in terms of sound absorption, low-frequency performance, and overall effectiveness in blocking sound. If you are looking to soundproof areas that are exposed to heavy noise, such as music studios, home theaters, or industrial buildings, rockwool will deliver superior results.

However, if your primary goal is thermal insulation or if you are working on a tight budget, fiberglass may be a suitable choice. It is a more affordable option, though it may not provide the same level of noise reduction, especially in situations where low-frequency noise is a concern.

For projects where soundproofing performance is crucial, investing in rockwool is likely the better option. Its higher density, superior fire resistance, and ability to absorb a broader range of sound frequencies make it the ideal choice for effective soundproofing.

Need help with soundproofing your space? Contact us today for expert advice on the best insulation solution for your needs!