Reading a Product EPD

What you are looking at

An Environmental Product Declaration (EPD) is a standardised document that reports the environmental impact of a construction product based on Life Cycle Assessment (LCA). It follows EN 15804 (the European standard for construction product EPDs) and is verified by an independent third party.

EPDs are typically 8-15 pages long, filled with tables of numbers in units most people have never encountered. They can look intimidating, but the structure is consistent and once you know what to look for, you can extract the key information in a few minutes.

This guide walks through each section of a typical EPD and explains what it means in practical terms.

Note. EPDs do not judge a product as 'good' or 'bad'. They are transparent data sheets - like nutrition labels for environmental impact. You use them to compare products, not to certify sustainability.

The front page: product and programme details

The first page identifies the product, the manufacturer, and the programme operator (the organisation that published the EPD). Key things to check here:

1.Programme operator

Who published the EPD - e.g. EPD International, BRE, IBU. Confirms third-party oversight.

2.Registration number

Unique identifier for the EPD. Use this to find it in the programme operator's database.

3.Validity date

EPDs typically last 5 years. An expired EPD should not be relied upon.

4.Declared unit

The basis for all data - e.g. 1 m², 1 kg, 1 m³. Essential for comparison.

5.Verifier and accreditation

The verification statement names the independent verifier and their accreditation body. If the verifier is missing or works for the manufacturer, treat the document as self-declared rather than third-party verified.

System boundaries: which stages are included

Every EPD must declare which lifecycle stages it covers. Look for a table or diagram showing stages A1 through D, with each stage marked as included (X), not declared (ND), or not relevant (NR).

The minimum requirement for a valid EPD under EN 15804 is stages A1-A3 (cradle to gate). Many EPDs also include A4-A5 (construction), B1-B7 (use), C1-C4 (end of life), and Module D (reuse/recycling credits).

When comparing two products, you must compare the same stages. If Product A reports A1-A3 and Product B reports A1-C4, the numbers are not directly comparable without isolating the A1-A3 figures from Product B.

Lifecycle stages in the boundary table

1
A1–A3
Mandatory minimum
2
A4–A5
Transport & install
3
B1–B7
Use phase
4
C1–C4
End of life
5
D
Reported separately

Watch out. Watch for EPDs that only declare A1-A3 for products with significant transport, installation waste, or end-of-life impacts. A product shipped from overseas may look good at cradle to gate but much worse when A4 transport is included.

Environmental impact results: the core data

This is the most important table in the EPD. It lists the environmental impact indicators for each lifecycle stage. Here is what the key indicators mean and how to interpret them.

Topic	Detail
GWP-total (kg CO2e)	Global Warming Potential, total. This is the embodied carbon figure. It combines fossil carbon, biogenic carbon, and land use change carbon. For most products, this is the number people care about most.
GWP-fossil (kg CO2e)	the portion of GWP from fossil fuel combustion and industrial processes. For non-bio-based products, this is usually very close to GWP-total.
GWP-biogenic (kg CO2e)	the portion from biological sources. For timber products, this is often a large negative number (carbon stored in the wood) that offsets the fossil emissions. EN 15804:2019 requires this to be reported separately.
GWP-luluc (kg CO2e)	the portion from land use and land use change. Captures emissions from clearing forests, draining peatlands, or converting natural land to agriculture. Most relevant for bio-based materials and products with agricultural inputs.
AP (mol H+ e or kg SO2e)	Acidification Potential. Higher values mean more contribution to acid rain. Relevant for products manufactured using high-sulphur fuels.
EP-freshwater (kg PO4e)	Eutrophication Potential for freshwater. Relates to nutrient pollution of rivers and lakes.
POCP (kg NMVOC e)	Photochemical Ozone Creation Potential. Measures contribution to ground-level smog from volatile organic compound and nitrogen oxide emissions. Higher for solvent-heavy paints, sealants, and combustion-intensive processes.
ODP (kg CFC-11e)	Ozone Depletion Potential. Usually very small for construction products, but relevant for some insulation blowing agents.
ADPE (kg Sb e)	Abiotic Depletion, elements. Measures consumption of scarce mineral resources. Relevant for products using rare metals.
ADPF (MJ)	Abiotic Depletion, fossil fuels. Total fossil energy consumed. This is a useful cross-check on the GWP figure.

Resource use and waste indicators

Below the impact results, most EPDs include additional tables covering resource use and waste generation.

Topic	Detail
PERE / PENRE (MJ)	Primary Energy from Renewable and Non-Renewable sources respectively. Shows the total energy input and its breakdown between renewable (hydro, wind, biomass) and non-renewable (coal, gas, oil, nuclear) sources.
SM (kg)	Secondary Material input. How much recycled or reclaimed material went into the product. A direct measure of recycled content.
RSF / NRSF (MJ)	Renewable and Non-Renewable Secondary Fuels. Energy from waste incineration or co-processing used in manufacturing.
HWD / NHWD / RWD (kg)	Hazardous Waste, Non-Hazardous Waste, and Radioactive Waste disposed. Indicates the waste burden of manufacturing.
CRU / MFR / EEE / EET	Components for Re-Use, Materials for Recycling, Exported Electrical Energy, and Exported Thermal Energy. These appear in the end-of-life stages and Module D.

Module D: beyond the system boundary

Module D reports the potential environmental benefits (or loads) from reuse, recycling, or energy recovery at end of life. It is always reported separately from stages A-C because it represents future potential, not current reality.

For steel, Module D often shows a large carbon credit because steel is highly recyclable and displaces virgin steel production. For timber, it may show an energy recovery credit if the wood is burned for energy at end of life. For concrete, it may show a credit from recycled aggregate use.

Module D numbers should be treated with caution. They depend on assumptions about future recycling rates, energy mixes, and market conditions 30-60 years from now. They are informative but should not be used to offset A1-A3 emissions in a like-for-like comparison.

Recycling credit

Material recovered as feedstock for new products. Common for steel, aluminium, and concrete aggregates. Usually the largest credit.

Reuse credit

Whole components recovered for direct reuse - bolted steel sections, reclaimed bricks, demountable partitions. Highest-value circular outcome.

Energy recovery

Material incinerated at end of life with the heat captured. Typical for timber, plastics, and biomass insulation. Displaces fossil energy.

Exported energy

Excess heat or electricity from end-of-life processing that is exported off-site to another user, displacing grid energy.

Tip. Some EPDs present a 'total' figure that combines A1-C4 with Module D, making the product look much better than its actual manufacturing footprint. Always look at A1-A3 separately as your primary comparison point.

How to compare two EPDs

You have two EPDs open side by side. Here is a checklist for making a fair comparison.

Topic	Detail
Same functional unit?	if one reports per m2 at R=1 and another per kg, you cannot compare directly. Convert to the same basis.
Same lifecycle stages?	compare A1-A3 with A1-A3, not A1-A3 with A1-C4.
Same EN 15804 version?	the 2013 and 2019 versions of EN 15804 handle biogenic carbon differently. Check which version each EPD uses. Mixing versions can create apparent differences that are purely methodological.
Same programme operator?	different programme operators have slightly different Product Category Rules (PCRs). Comparisons within the same programme are more reliable than across programmes, though EN 15804 alignment makes cross-programme comparison increasingly valid.
Both currently valid?	check the expiry dates. Comparing a 2024 EPD with a 2018 EPD may reflect changes in manufacturing and energy mix rather than genuine product differences.
Product-specific vs industry average?	a product-specific EPD reflects the actual manufacturer's data. An industry-average EPD reflects a sector average. Comparing the two is possible but understand that the industry average will mask best and worst performers.
Same reference service life (RSL)?	if the EPDs include use-phase or end-of-life modules, check the assumed product lifespan. A product specified to last 30 years compared head-to-head with one specified to last 60 years hides the fact that the shorter-lived option must be replaced within the building's life. Normalise by dividing impacts by RSL, or compare on a per-year-of-service basis.

Quick reference: what to look at first

If you only have two minutes with an EPD, check these five things in order.

1.Check the declared unit

Know what quantity the data refers to before comparing anything.

2.Read GWP-fossil (A1–A3)

The headline carbon number. Lower is better - but only compare like-for-like.

3.Check the system boundary

A1–A3 only? A1–C4? Module D? Know what's included.

4.Confirm validity

Expired EPDs should not be used for specification decisions.

5.Note recycled content

Look for the SM (secondary material) indicator in the resource use table.

Tip. On Matera, EPD data is extracted and displayed on product listings where suppliers have uploaded it. The full EPD document is available to download for detailed review.