# How do I calculate the carbon footprint of an exhaust silencer?

Canonical: https://senseible.earth/answers/exhaust-silencer-carbon-footprint-per-unit

Weigh the steel or stainless steel shell, pipes and baffles per silencer and multiply by supplier figures. Add bending, welding, coating and testing energy, then divide the plant's energy by units passed. Count catalysts separately if fitted.

## Material

- Steel or stainless steel sheet and tube.
- Packing and heat shields.
- Catalytic converter if fitted.

## Process

- Tube bending and pressing.
- MIG welding.
- Heat-resistant coating and leak testing.

## Per unit

Report per silencer by vehicle type, and show the catalytic converter as its own line.

## Worked example: exhaust silencer unit per unit (one month)

- Electricity: 30,000 kWh x 0.710 = 21,300 kg CO2
- LPG: 1,000 kg x 2.98 = 2,980 kg CO2
- Units produced: 30,000
- Plant total: 24,280 / 30,000 = 0.809 kg CO2 per unit
- Add steel and catalyst 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](https://senseible.earth/calculators/product-carbon-footprint)
- [Sheet metal stamping footprint](https://senseible.earth/answers/sheet-metal-stamping-carbon-footprint-per-kg)
- [Stainless steel utensils footprint](https://senseible.earth/answers/stainless-steel-utensils-carbon-footprint-per-kg)
- [Automobile industry](https://senseible.earth/industries/automobile)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-20.