How does glass wool compare to rock wool and fiberglass for thermal insulation? | Insights by FUNAS

1. What are the thermal performance differences between glass wool, rock wool, and fiberglass?

Thermal performance is measured by the R-value, which indicates the material's resistance to heat flow. Glass wool typically has an R-value between R-2.9 to R-3.8 per inch of thickness, while rock wool ranges from R-3 to R-3.3 per inch. This suggests that rock wool offers slightly superior thermal insulation per inch compared to glass wool. Fiberglass, made from fine strands of glass, also provides effective thermal insulation but may have a lower R-value per inch compared to rock wool.

2. How do these materials compare in terms of fire resistance?

Fire resistance is a critical factor in insulation materials. Rock wool is non-combustible and can withstand temperatures above 1000°C without melting or emitting harmful gases, making it ideal for fire-rated constructions and industrial applications requiring stringent fire safety measures. Glass wool, while also non-combustible, begins to melt at around 700°C and may release toxic fumes in the event of a fire.

3. What are the sound insulation properties of glass wool, rock wool, and fiberglass?

Both rock wool and fiberglass offer sound absorption properties, but their effectiveness varies. Rock wool's denser composition provides excellent sound insulation, particularly in environments with high noise levels, such as factories, theaters, and recording studios. Glass wool, with its lightweight, fibrous structure, effectively reduces noise transmission, making it suitable for residential buildings, offices, and schools where noise control is important.

4. How do these materials perform in moist environments?

Moisture resistance is crucial for maintaining insulation performance. Rock wool is highly resistant to moisture and water absorption, maintaining its performance even in damp conditions, making it ideal for use in basements, bathrooms, and other areas prone to humidity. Glass wool is generally resistant to moisture, but prolonged exposure can reduce its insulating properties and lead to mold growth if not properly installed.

5. What are the environmental impacts and sustainability of these materials?

Both materials are environmentally friendly options, but their sustainability profiles differ. Glass wool is made from recycled glass, making it an eco-friendly option with a lower environmental impact. However, the production process can be energy-intensive. Rock wool utilizes abundant natural resources and recycled content, is fully recyclable, and has a longer lifespan, contributing to its sustainability.

6. How do the costs of glass wool, rock wool, and fiberglass compare?

Cost considerations are essential in procurement decisions. Fiberglass insulation is generally more cost-effective, with prices around $0.50 per square foot. Rock wool insulation is typically more expensive, costing about $0.62 per square foot. While rock wool has a higher initial cost, its superior thermal performance and durability may lead to long-term energy savings and reduced replacement costs.

7. What are the installation considerations for these insulation materials?

Both materials are available in batts, rolls, and blankets and can be installed by cutting them to fit various spaces. Protective gear, such as gloves, masks, and goggles, is recommended during installation to prevent skin and eye irritation. Proper installation is crucial to ensure optimal performance and longevity of the insulation.

8. How does FUNAS insulation stand out in the market?

FUNAS insulation materials are renowned for their high thermal performance, superior fire resistance, and environmental sustainability. Manufactured using advanced technologies and high-quality raw materials, FUNAS products offer durability and efficiency, making them a preferred choice for both residential and industrial applications.

• Angi, "Mineral Wool vs. Fiberglass Insulation: Pros, Cons, and Cost," October 2025
• Wafa Glasswool, "Glass Wool vs. Rock Wool: A Comparative Analysis," July 2024
• Mirror Review, "Comparing Insulation: Rockwool vs. Fiberglass," August 2024