Insulation

Glass Wool.

Glass wool has a lower CO₂ footprint than stone wool, but both are good choices from a lifecycle perspective — the energy savings they provide are many times greater than production CO₂.

Key Figures

Carbon Footprint (GWP): 0.85 kg CO₂-eq/kg
Density: 10–50 kg/m³
Expected Lifespan: 50+ år

What is glass wool?

Glass wool is made from melted glass — typically with up to 80% recycled glass — and spun into fine fibres. It is light, inexpensive, and has good insulating capacity. Used primarily for attic insulation and lightweight facade constructions. Carbon footprint is lower than rock wool because the melting temperature is lower.

Carbon Footprint Compared

Cellulose insulation 0.12 kg CO₂/kg

Glass wool ← this material 0.85 kg CO₂/kg

Mineral wool (stone wool) 1.05 kg CO₂/kg

EPS 3.29 kg CO₂/kg

Negative carbon footprint (green) indicates carbon storage. Data based on EPD averages from ECO Platform and estimates per EN 15804.

Typical Applications

check_circle Attic insulation
check_circle Exterior walls in lightweight construction
check_circle Partition walls with acoustic requirements
check_circle Ventilation ducts

In Renovation

Glass wool is the classic choice for retrofitting insulation in older attics. Easy to blow into attic spaces and install in rafter bays. Inexpensive and effective solution for a homeowner with a limited budget.

Questions about glass wool

Is glass wool cheaper than rock wool?

Typically yes — glass wool is 10–20% cheaper than rock wool for comparable properties. It is slightly more compressible and lighter, but has slightly lower fire safety and sound absorption.

Can glass wool be used outdoors?

Glass wool is not suitable for moisture-exposed structures. It loses insulating capacity when absorbing moisture. For exterior facade insulation, rock wool facade batts approved for the purpose should be used.

How is glass wool disposed of?

Glass wool can be delivered to specialist reception facilities. Isola and other producers offer take-back programmes. It should not be mixed with regular construction waste.

What is the right density for different purposes?

Low density (10–16 kg/m³) for loose-fill attic insulation. Medium density (25–35 kg/m³) for walls. High density (50+ kg/m³) for roofs and facades.

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