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Skill Claude Desktop · Claude Code

# /epd-compare

Side-by-side environmental impact comparison with LEED MRc2 check

[Install ↓](#install) [View on GitHub →](https://github.com/AlpacaLabsLLC/skills-for-architects/tree/main/skills/epd-compare) [New to skills? →](/articles/claude-code-cheat-sheet) [All skills →](/skills)

[Specifications](/skills?tag=specifications) [Analysis](/skills?tag=analysis)

## What it does

Type `/as: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:**

1.  Open **Customize** → **Browse plugins**
2.  Click **+** → **Add marketplace from GitHub**
3.  Enter `AlpacaLabsLLC/skills-for-architects`
4.  Install **Architecture Studio**

**Claude Code (terminal):**

```
claude plugin marketplace add AlpacaLabsLLC/skills-for-architects
claude plugin install as@skills-for-architects
```

Or symlink just this skill:

```
git clone https://github.com/AlpacaLabsLLC/skills-for-architects.git
ln -s $(pwd)/skills-for-architects/skills/epd-compare ~/.claude/skills/epd-compare
```

## Usage

After parsing or researching EPDs:

```
/as:epd-compare compare the CLT EPDs I just found
```

Or with inline data:

```
/as:epd-compare concrete A: 320 kg CO2e/m3, concrete B: 280 kg CO2e/m3, concrete C: 410 kg CO2e/m3
```

## What 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

-   [`/as:epd-parser`](/skills/epd-parser) — parse EPD PDFs to get data for comparison
-   [`/as:epd-research`](/skills/epd-research) — find more EPDs to compare
-   [`/as:epd-to-spec`](/skills/epd-to-spec) — use the lowest GWP from the comparison as a spec threshold

## Related skills

[01

### /epd-parser

Extract structured environmental impact data from EPD PDFs

→](/skills/epd-parser) [02

### /epd-research

Search registries and manufacturer sites for Environmental Product Declarations

→](/skills/epd-research) [03

### /epd-to-spec

CSI specification sections with EPD requirements and GWP thresholds

→](/skills/epd-to-spec)

[← All skills](/skills) [EPD to Spec →](/skills/epd-to-spec)