How do I calculate the carbon footprint of a vehicle headlamp?
Weigh the polycarbonate lens, housing, reflector and electronics per lamp and multiply by supplier figures. Add moulding, coating, metallising and assembly energy, then divide the plant's energy by lamps made.
Material
- Polycarbonate lens and PP or other plastic housing.
- Reflector and its coating.
- Bulbs or LED modules, wiring and connectors.
Process
- Injection moulding.
- Hard coating the lens and vacuum metallising the reflector.
- Assembly and aiming tests.
Per unit
Report per lamp by vehicle type. LED modules add electronics that a bulb lamp does not have.
Worked example: plant energy per unit (one month)
- Electricity: 120,000 kWh x 0.710 = 85,200 kg CO2
- Lamps made: 60,000
- Plant total: 85,200 / 60,000 = 1.420 kg CO2 per unit
- Add plastics, reflector and lighting parts for the full figure
Inputs are illustrative; use your own bills and production records.
What Senseible does here
Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.
- Product carbon footprint calculator
- Injection moulding footprint
- LED bulb footprint
- Wiring harness footprint
- Automobile industry
Sources: GHG Protocol Product Standard, ISO 14067:2018, Carbon footprint of products (iso.org), IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults), CEA CO2 Baseline Database, version 21.0
Last reviewed 2026-10-21.