RE2020: actual measurement vs lump-sum value
the construction site carbon lever
RE2020 uses conservative lump-sum values for construction site carbon. Actually measuring your site emissions with Efficarbone produces a precise and traceable carbon assessment — a lever that becomes critical as thresholds tighten.
The RE2020 mechanism: lump sum or measurement
RE2020 calculates a building's overall carbon footprint by summing several indicators. Among them, construction site carbon (items A4 to A9 per EN 15978) covers the emissions from the construction phase: transport, machinery, waste, site facilities, personnel travel.
When no actual data is available, RE2020 applies a lump-sum value. This value is conservatively calibrated — it deliberately overestimates construction site emissions to incentivise actual measurement.
Lump-sum value (default)
Applied automatically if the project owner does not provide an actual measurement. Intentionally inflated.
- — Penalises the building's overall Ic assessment
- — Reduces the margin available against RE2020 thresholds
- — No recognition of logistics efforts
Actual measurement (Efficarbone)
Replaces the lump sum in the RE2020 calculation if the measurement is traced and documented.
- — Reflects actual construction site emissions
- — Often lower than the lump sum if the site is well managed
- — Frees up margin against RE2020 thresholds
The difference between lump sum and actual measurement represents a RE2020 compliance lever. For a building that is close to the carbon threshold, this lever can make the difference between compliance and non-compliance — without modifying material choices or the architectural design.
RE2020 thresholds: a tightening trajectory
RE2020 imposes increasingly demanding carbon thresholds on a three-milestone calendar. At each stage, the margin for manoeuvre decreases — and every emission item counts more.
| Milestone | Effective date | Requirement | Impact on construction site carbon |
|---|---|---|---|
| 2025 milestone | 1 January 2025 | First overall Ic thresholds applicable | The lump sum is still acceptable for most projects |
| 2028 milestone | 1 January 2028 | Thresholds lowered by approximately 15 to 25% | The lump sum starts to weigh — actual measurement becomes an advantage |
| 2031 milestone | 1 January 2031 | Lowest thresholds in the trajectory | The lump sum becomes a real handicap — measurement is virtually essential |
The lower the thresholds, the more the conservative lump-sum value weighs in the overall assessment. A project owner who measures their construction site carbon now accumulates prior data and refines their ability to optimise the construction phase on future projects.
Traceability: what RE2020 expects
For an actual measurement to replace the lump-sum value in the RE2020 calculation, it must meet traceability and documentation requirements. Efficarbone is designed to produce this evidence:
Traceable emission factors
Each factor used comes from the Base Empreinte (ADEME) with identifier, vintage and source. No in-house factors or opaque coefficients.
Confidence level per data point
Each item is qualified: actual measurement (invoice, record), documented estimate, or default value. The verifier knows what is measured and what is estimated.
Coverage of all 6 EN 15978 items
A4 (supply), A5a (site facilities), A5b (personnel travel), A5c (machinery), A5d (waste), A5e (temporary equipment). No item overlooked.
Auditable report
The Efficarbone assessment produces a structured report that can be integrated into the RE2020 file — usable by the inspection body and the certifier.
Project owner strategy: measure early, capitalise
Measuring construction site carbon is not just a one-off compliance tool — it is a strategic asset for project owners who operate multiple sites:
Benchmark
Compare construction site carbon assessments across projects. Identify the items with the greatest variances — and the best-performing contractors.
Calibrate tenders
Use past assessments to formulate realistic construction site carbon criteria in future tenders — neither too lenient nor unachievable.
Document the trajectory
Build a track record of verifiable data for CSRD reporting, environmental claims, and institutional communications.
A project owner who starts measuring today will have, by the 2028 milestone, 3 years of comparative data — an advantage their competitors will not be able to match.
Frequently asked questions
Efficarbone documents actual construction site emissions (modules A4-A5). This data can supplement or refine the RE2020 calculation as thresholds tighten. Substitution of lump sums depends on the regulatory framework in force and acceptance by the verifier.
Ic construction thresholds (including component carbon + construction site carbon) vary by building type and tighten in stages (2025, 2028, 2031). For multi-unit housing, the 2025 threshold is 740 kg CO2/m2. The construction site component (A4-A5) typically represents 5 to 15% of the total.
No, RE2020 allows the use of lump-sum values for construction site carbon. Actual measurement is a voluntary approach that improves assessment accuracy and prepares operators for the expected tightening of traceability requirements.
Document your construction site carbon with actual measurement
Efficarbone measures construction site carbon (items A4-A5, EN 15978) using ADEME factors. Traceable data for RE2020, BEGES and ESRS E1 reporting.
Complete your carbon approach
ESRS E1 — climate & CSRD
CSRD carbon reporting requirements for real estate.
En savoir plus →CBCA Label
Accredited Low Carbon Construction Site: the label operated by IRICE.
En savoir plus →Public procurement clauses
Integrating construction site carbon into your award criteria.
En savoir plus →Directive 2024/825
Substantiating your carbon claims under the new obligations.
En savoir plus →