How much CO2 does denim washing add per garment?
Add the laundry's boiler fuel, dryer fuel and electricity for a month, multiply each by its emission factor, and divide by the pieces washed. Heavy stone and enzyme washes take far more heat and machine time than a rinse, so split by wash recipe where you can. Dryers often use most of the heat.
What goes into a laundry's figure
- Boiler fuel for hot water and steam: PNG, LPG, coal, briquettes or furnace oil.
- Tumble dryer fuel, if dryers are gas-fired rather than steam-heated.
- Electricity for washers, extractors, dryers, laser and ozone machines, compressors and the ETP.
- Chemicals, enzymes and pumice are Scope 3 purchased goods; add them if the buyer asks for a cradle-to-gate figure.
Splitting by wash recipe
Pieces washed is a fair divisor only when recipes are similar. Otherwise give each recipe a weight from metered steam or gas per batch, or from machine minutes times load, and share the month's emissions by weighted pieces.
Re-measure the weights when you change a recipe, for example when ozone fading replaces a bleach step.
Laser and ozone: what changes
Laser and ozone finishing replace hand scraping, potassium permanganate spray and some bleaching baths. They cut water, chemicals and hot rinse steps, but they add electricity. Count both sides: lower boiler fuel per piece, higher kWh per piece at 0.710 kg CO2 each.
Keeping washing separate from stitching
Report laundry per piece as its own stage. Buyers add it to fabric, stitching and freight, and a combined factory figure hides where the heat goes. If the laundry is a jobworker, it is your Scope 3; ask for its monthly bills and wash counts.
Worked example: one month at a denim laundry
- Boiler PNG: 8,000 scm x 2.05 = 16,400 kg CO2
- Dryer LPG: 6,000 kg x 2.98 = 17,880 kg CO2
- Electricity: 50,000 kWh x 0.710 = 35,500 kg CO2
- Total: 69,780 kg CO2 for 100,000 pieces = 0.70 kg CO2 per piece on average
- By recipe: 40,000 stone and enzyme washes at weight 3, 60,000 rinses at weight 1, so 180,000 weighted pieces
- 69,780 / 180,000 = 0.388 kg per weighted piece; stone wash 1.16 kg, rinse 0.39 kg per piece
Recipe weights are illustrative; take them from your own batch metering.
What Senseible does here
Senseible reads the laundry's PNG, LPG, coal and electricity invoices (Scope 1 at IPCC 2006 defaults, Scope 2 at 0.710 kg CO2 per kWh) and keeps chemical purchases in the Scope 3 evidence trail. Product reports are self-declared drafts; wash counts and recipe weights come from your production register.
Sources: ISO 14067:2018, Carbon footprint of products, 2006 IPCC Guidelines, Volume 2: Energy, CEA CO2 Baseline Database, version 21.0
Last reviewed 2026-10-18.