For EPBD compliance you will need a certified life-cycle assessment, because the life-cycle GWP figure has to be calculated to EN 15978 and disclosed on the energy performance certificate. Pre-assessment does not replace that. It answers a different question — whether the design you are pursuing will produce an acceptable number — at a stage where the answer can still change the design.
Confusing the two is the expensive mistake. Teams either treat an early estimate as compliance evidence, or defer all carbon work to the certified assessment and discover the result when redesign costs real money.
The short version
- Certified LCA — verified, EPD-backed, performed late, produces the disclosed figure. Mandatory.
- Pre-assessment — indicative, generic-data-backed, performed at concept, produces a decision. Not mandatory, and not evidence.
- The disclosed number is largely determined by concept-stage choices — frame, retention, envelope — long before anyone calculates it.
- The cost of changing a structural decision rises steeply through design. The carbon consequence of that decision does not.
- From 2028 the figure appears on the EPC for new buildings over 1,000 m², and from 2030 for all new buildings (full timeline).
- Use pre-assessment to steer, certified LCA to certify. Neither substitutes for the other.
What is the actual difference?
Purpose. A certified LCA produces a defensible number for a document. A pre-assessment produces a comparison between options.
| Pre-assessment | Certified LCA | |
|---|---|---|
| Answers | Which option is lower? | What is this building’s figure? |
| Data | Generic datasets | Product-specific EPDs |
| Timing | Concept, while design can change | Technical design, once fixed |
| Output | A decision | The disclosed figure |
| Required? | No | Yes, from 2028 |
Data. A certified assessment expects product-specific EPDs where products are known. Pre-assessment uses generic datasets, because at concept stage no product is chosen (EPD vs generic dataset).
Precision. Certified work aims to be right about a building. Pre-assessment aims to be right about a difference — which of two frames is lower, and roughly by how much. That is a far easier question, and generic data answers it reliably.
Timing, which is the crux. The certified assessment happens when the design is fixed enough to assess. By definition, that is after the decisions have been taken.
Why can’t you just wait for the certified assessment?
You can. It is compliant. It is also the most expensive way to find out.
Most of a new building’s upfront carbon is committed by a handful of early decisions: the structural system, whether existing fabric is retained, the facade build-up, and the grid. Those are settled in the first months of design.
A certified assessment arriving at technical design tells you the consequence of decisions that are now costly to revisit. If the number is comfortable, that is fine. If it is not, the options are a redesign nobody has budgeted for, or a disclosed figure you would rather not disclose.
Pre-assessment moves the discovery earlier. That is the entire value proposition — not accuracy, timing.
What does “not compliance evidence” actually mean?
It means an indicative figure cannot be put forward as the disclosed GWP, and should not be presented internally as though it could.
In practice, be explicit in three places:
- Board and investor reporting. An indicative early figure described as “our building’s carbon” will be read as verified. Label it.
- Client and tender documents. If a carbon target is contractual, state which assessment settles it.
- Marketing. A number quoted from a concept-stage estimate is a claim you may have to withdraw.
This is a governance point as much as a technical one. The regulation puts a carbon figure on a certificate attached to a saleable asset. The gap between an estimate and that figure is a disclosure risk, and it is managed by saying which is which.
How do the two work together?
They are sequential, and the first should feed the second.
Concept. Pre-assess the whole building on generic data. Compare structural options and, on an existing asset, test retention against demolition — usually the largest single lever available (refurbishment vs demolition). Output: a decision and a baseline.
Developed design. Refine as products firm up. Watch the delta against the baseline. Output: early warning if the number is drifting.
Technical design. Commission the certified assessment. A good pre-assessment hands over a clean quantity model and a documented boundary, so the assessor is verifying and refining rather than starting from nothing (modules A to C).
Certification. The verified figure reaches the EPC.
Done this way the certified assessment usually gets cheaper, because most of its input already exists and is structured.
What should a developer put in place now?
Baseline the live pipeline. Anything completing from 2028 is in scope and is being designed now. You cannot manage a figure you have never calculated.
Put a carbon question at concept gateway. Not a target — a number and a comparison, at the point the frame is chosen.
Decide who owns the figure. Design team, sustainability consultant, or in-house. In most organisations this is genuinely unassigned, which is how it reaches technical design unexamined.
Write the estimate-versus-assessment distinction into reporting templates, once, so nobody has to remember it.
Frequently asked questions
Does pre-assessment satisfy the EPBD? No. The disclosed figure must be a full EN 15978 calculation. Pre-assessment informs the design that produces that figure.
Is a certified LCA needed on every project? For new buildings over 1,000 m² from 2028 and all new buildings from 2030, the life-cycle GWP must be calculated and disclosed on the EPC.
How accurate is a pre-assessment? Accurate enough to rank options, not to certify a building. Its reliability lies in comparing alternatives on a consistent basis — the difference between two options is far more robust than either absolute value.
Can it be reused for certification? Not as the figure, but its quantities, boundary and assumptions transfer, which is where most of the effort sits.
What if the certified figure comes in worse than the estimate? It sometimes will, particularly if generic factors were optimistic or quantities grew. That is the argument for baselining early and tracking the delta, rather than comparing two numbers years apart and having no idea which assumption moved.
Where this leaves you
The regulation requires a certified assessment. It does not require you to be surprised by it.
Elementa is pre-assessment: an indicative whole-building figure on Elementa’s seven building systems, on the EN 15978 module boundary, at concept stage, built to be handed to a certified assessor rather than to replace one. Every figure carries its confidence, and the disclaimer travels with the number rather than sitting in a footnote.
Early figures are indicative and directional. They inform decisions; they do not replace a verified life-cycle assessment or an energy performance certificate.
Sources: Directive (EU) 2024/1275 (EPBD recast) — global warming potential of buildings; European Commission — calculation framework for new building life-cycle GWP. Verified August 2026.