Glass sustainability

Flat (float) glass

Producer EPDs (EN 15804+A2, cradle-to-gate A1–A3) give standard 4 mm float glass at about 9.64 kg CO₂e/m² (Guardian) and 10.3 kg CO₂e/m² (AGC). The functional unit is per m² of 4 mm glass, not per kg — glazing is specified by area. Low-carbon float variants sit lower (e.g. producer "NEXA"/low-carbon ranges). A derived per-kg figure (~1.0 kg CO₂e/kg) exists for rough mass work but the per-m² EPD is the primary result.

Container glass

FEVE's European LCA gives container glass at about 0.95 kg CO₂e/kg at ~32% cullet, on a cradle-to-cradle boundary. Because the boundary and functional unit differ from flat glass, the two cannot be compared directly — MatQuo's comparison tools block that pair rather than show false precision.

Cullet & what changes the footprint

Recycled glass (cullet) is the biggest lever: melting cullet needs less energy than raw batch, so higher cullet lowers energy and CO₂ (roughly a few percent per +10% cullet for container glass). Furnace energy source and pull rate also matter. EU glass packaging recycling was 74.9% in 2023, just below the 75% 2030 target.

Transport

Glass is heavy, so freight mass is significant. Estimate sheet weights with the flat glass weight calculator (2500 kg/m³) and lane emissions with the freight CO₂ calculator.

Methodology & limitations

Flat glass: cradle-to-gate (A1–A3), per m² of 4 mm, producer EPDs — datapoints, not a sector average. Container glass: cradle-to-cradle, per kg, FEVE 2016 LCA (verify against newer LCAs). The two boundaries are not interchangeable.