Cat 11 Starter Kit: Use of Sold Products

If product use drives emissions: define a functional unit, estimate use-phase impact, and document assumptions

Scope 3, Made PracticalCoreStarter Kit30 min

What you'll accomplish

  • Determine if Cat 11 applies to your products/services
  • Define a simple functional unit (per unit, per hour, per transaction, etc.)
  • Build a minimum viable estimate of use-phase emissions
  • Create an improvement plan (better usage data and energy assumptions)

Who this is for

Sustainability teams

Defining use-phase Scope 3 assumptions

Product teams

Providing product usage context and units

Finance teams

Validating disclosure assumptions

Quick start (60 minutes)

  • Run the relevance test (Template 1)
  • Define functional unit (Template 2)
  • Document usage assumptions (Template 3)
  • Draft methods note (Template 4)

Relevance test

Cat 11 is relevant when:

  • •customers consume energy or fuel to use your product (devices, equipment, vehicles, appliances)
  • •or your product causes significant energy use downstream

If your offering does not materially drive downstream energy use, Cat 11 may be low or not applicable.

Templates

Template 1 — Relevance Test

Cat 11 Test

Does our product require energy/fuel during customer use? (Y/N)
Is that energy/fuel likely material? (Y/N)

If "No" → document Cat 11 as not applicable or low relevance.

Template 2 — Functional Unit Definition

| Product | Functional unit | Why this unit | Notes |
|---|---|---|---|

Examples:

  • • per device-year
  • • per operating hour
  • • per transaction
  • • per customer-month

Template 3 — Usage Assumptions Log

| Product | Assumption | Value | Source | Confidence (H/M/L) | Notes |
|---|---|---:|---|---|---|

Template 4 — Cat 11 Methods Note (copy/paste)

Cat 11 Methods Note (Internal)

Scope:
Functional units:
Usage assumptions:
Data sources:
Limitations:
Plan to improve:

Common pitfalls

  • ✗Overconfidence in assumptions (document uncertainty)
  • ✗No functional unit (numbers become meaningless)
  • ✗Treating Cat 11 as universal (it's product-dependent)

Change log

v1.0 (2026-01): Latest release