EPD Compare
A Claude Code skill that compares 2+ products on GWP and other environmental impact metrics. Validates comparability, normalizes declared units, generates percentage deltas, and checks LEED v4.1 MRc2 eligibility.
What it does
Type /epd-compare with products to compare — from parsed EPDs, research results, sheet references, or pasted data. The skill validates comparability (declared units, system boundaries, PCR alignment), generates side-by-side impact tables, calculates percentage deltas relative to the lowest-impact option, and checks LEED v4.1 MRc2 eligibility.
Install
Claude Desktop:
- Open Customize → Browse plugins
- Click + → Add marketplace from GitHub
- Enter
AlpacaLabsLLC/skills-for-architects - Install the Sustainability plugin
Claude Code (terminal):
claude plugin marketplace add AlpacaLabsLLC/skills-for-architects
claude plugin install 05-sustainability@skills-for-architectsOr symlink just this skill:
git clone https://github.com/AlpacaLabsLLC/skills-for-architects.git
ln -s $(pwd)/skills-for-architects/plugins/05-sustainability/skills/epd-compare ~/.claude/skills/epd-compareUsage
After parsing or researching EPDs:
/epd-compare compare the CLT EPDs I just foundOr with inline data:
/epd-compare concrete A: 320 kg CO2e/m3, concrete B: 280 kg CO2e/m3, concrete C: 410 kg CO2e/m3What it checks before comparing
- Declared unit alignment — warns if units differ and normalization isn’t possible
- System boundary — flags cradle-to-gate vs. cradle-to-grave mismatch
- PCR alignment — notes when products use different Product Category Rules
- EN 15804 version — flags +A1 vs. +A2 differences (AP/EP units may differ)
- Validity — marks expired EPDs
- EPD type — distinguishes product-specific from industry-average
Sample: CLT comparison
Generated from: three CLT EPDs (Stora Enso, Arboreal, Kalesnikoff)
Comparability check: ✓ Declared unit: All 1 m3 ✓ All product-specific, third-party verified ⚠ System boundary: Stora Enso cradle-to-grave, others cradle-to-gate — A1-A3 comparison valid ⚠ Standard: Stora Enso & Arboreal EN 15804+A2, Kalesnikoff ISO 21930 — GWP comparable ⚠ Biogenic carbon: Use GWP-fossil for fair comparison across CLT producers
| Metric | Stora Enso | Arboreal | Kalesnikoff | Unit |
|---|---|---|---|---|
| GWP-fossil (A1-A3) | 52.6 | 111 | 124.5 | kg CO2e/m3 |
| GWP-biogenic (A1-A3) | -762 | -857 | — | kg CO2e/m3 |
| GWP-total (A1-A3) | -708 | -743 | 124.5 | kg CO2e/m3 |
| PENRE (A1-A3) | 816 | 1,700 | 2,352 | MJ/m3 |
GWP-fossil (relative to lowest): Stora Enso — baseline · Arboreal +111% · Kalesnikoff +137%
Recommendation: Stora Enso is the clear leader on fossil GWP — less than half of the North American alternatives. For North American projects, Kalesnikoff has a shorter supply chain. All three qualify for LEED MRc2 Option 1 and Option 2.
Output saves as a markdown comparison report.
Pairs with
/epd-parser— parse EPD PDFs to get data for comparison/epd-research— find more EPDs to compare/epd-to-spec— use the lowest GWP from the comparison as a spec threshold
Related skills
EPD Parser
Extract structured environmental impact data from EPD PDFs
EPD Research
Search registries and manufacturer sites for Environmental Product Declarations
EPD to Spec
CSI specification sections with EPD requirements and GWP thresholds