Choosing a building product involves more than accepting a “green” label. An Environmental Product Declaration (EPD) gives a project team documented environmental information to examine alongside specifications, price and availability. For owners and contractors, the useful question is whether the declaration supports the comparison being made.
What an EPD tells you
An EPD reports environmental information based on a product life cycle assessment. It identifies the product and describes the assessment boundaries and results. Germany’s Federal Environment Agency explains that these declarations support material selection, documentation and building life cycle assessments, with independent review as part of quality assurance. See its overview of construction product EPDs.
Treat the document as evidence to examine. Its existence alone does not establish that a product is the best choice for your project. Ask the supplier to identify the actual product covered, the declaration’s validity dates and its verification information.
Start with the carbon result and its unit
Global warming potential (GWP) expresses climate impact in carbon dioxide equivalents. An EPD reports that result relative to a stated quantity of material. New York City’s EPD guidance explains this relationship and the role of Product Category Rules, which establish the basis for collecting data for a product type.
Before placing two figures side by side, check the units and the products’ intended function. A number per unit of mass cannot simply be ranked against a number per unit of volume. Ask your designer or supplier to explain the conversion and the quantity required for the same application.
Check which life cycle stages are included
Many declarations report stages A1–A3, commonly called cradle-to-gate: raw material supply, transport to manufacturing and production. That figure does not automatically include delivery to your site, installation, maintenance or disposal. The NYC guidance describes both this common boundary and the broader life cycle stages an EPD may cover.
Write the reported boundary next to every figure in your comparison. If one document covers production and another includes additional stages, pause before drawing a conclusion. Request a comparison on a consistent basis.
Keep the product decision connected to the building
The U.S. Environmental Protection Agency describes production-stage embodied carbon as emissions associated with extraction, transport and manufacturing. Its construction materials resource page also points to tools for evaluating materials and guidance on reuse. These resources provide a starting point for discussing the carbon consequences of a purchase.
Use that discussion alongside the project’s technical requirements. For a roofing or renovation project, ask the responsible professional to confirm that an alternative meets the required performance before approving a substitution. Our guide to sustainable materials and construction techniques provides related background on material selection.
A practical supplier checklist
- Request the complete EPD and confirm which product it covers.
- Record its validity dates, verification details and Product Category Rules.
- Note the declared unit, GWP result and included life cycle stages.
- Ask whether competing products provide equivalent project performance and comparable data.
- Save the declaration with the approved specification and purchasing record.
If a supplier cannot answer a comparison question, record it as unresolved rather than filling the gap with an assumption. A transparent selection record is more useful than an unsupported claim that one product is universally greener.
