# What is the carbon footprint of rock wool insulation per kg?

Canonical: https://senseible.earth/answers/rock-wool-insulation-carbon-footprint-per-kg

Rock wool is made by melting basalt and slag, often in a coke fired cupola, then spinning fibres and curing a binder. Coke combustion is the main CO2; carbonate fluxes add process CO2. Divide by kg of finished product.

## Sources

- Scope 1: coke or gas in the melter, curing oven fuel.
- Process CO2 from any limestone or dolomite in the charge.
- Scope 2: spinning and fan electricity.
- Scope 3: binder, packaging, slag bought in.

## Electric melters

An electric melter moves most of the CO2 into Scope 2 and cuts it if the power is renewable.

## 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.

- [Glass wool per kg](https://senseible.earth/answers/glass-wool-insulation-carbon-footprint-per-kg)
- [Limestone calcination CO2](https://senseible.earth/answers/process-co2-from-limestone-calcination)

Sources: [IPCC 2006 Guidelines](https://www.ipcc-nggip.iges.or.jp/public/2006gl/), [CEA CO2 Baseline Database](https://cea.nic.in/cdm-co2-baseline-database/?lang=en), [GHG Protocol Corporate Value Chain (Scope 3) Standard](https://ghgprotocol.org/corporate-value-chain-scope-3-standard)

Last reviewed 2026-10-22.