For decades, a building's energy performance was measured solely by its operational consumption. Today, the energy embodied in materials — embodied energy — accounts for about a quarter of the primary energy of a new low-energy building, and roughly half the carbon balance of a high-performance building heated from renewablesSFOE, "Embodied energy in new buildings": 42.0 kWh/m²·yr of embodied energy out of 158.9 kWh/m²·yr in total for a low-consumption apartment block, i.e. about 26 %.Office fédéral de l'énergie (OFEN) / SuisseEnergie — L'énergie grise dans les nouveaux bâtiments — Guide pour les professionnels. This has become a central issue, and Geneva's legal framework now reflects it directly.
Embodied energy (or incorporated energy) refers to all the energy required to produce a building: raw material extraction, industrial processing, transport, on-site installation, maintenance, replacement over the building's life, then demolition and end-of-life treatment.
It is expressed in non-renewable primary energy — historically in MJ/m² of energy reference area (SRE), or in kWh/m²·an annualised over the building's standard service life (60 years per SIA 2032 technical guidelineMinergie, embodied energy calculation method (2021): building service life of 60 years, component amortisation periods taken from the SIA 2032 technical guideline.Minergie Suisse — Berechnung der Grauen Energie und der Treibhausgasemissionen bei Minergie-ECO (v1.3)). But the indicator now used by Geneva's legal framework is not energy: it is the embodied carbon, i.e. the balance of greenhouse gas emissions expressed in kg CO₂-eq/m²·an.
Life Cycle Assessment (LCA) — or Analyse du Cycle de Vie (ACV) — is the standardised method for quantifying a building's environmental impact from "quarry to landfill". In Switzerland, the technical guideline SIA 2032 (life cycle inventory method) and the European standard EN 15978 structure the LCA into four main modules.
In practice, Geneva's regulatory calculation relies on modules A1–A5 (material manufacturing, transport and installation) and B4 (replacements over the service life), which make up most of the embodied energy for a well-designed new building. Modules C and D are included in comprehensive approaches (SNBS, DGNB).
Embodied energy varies considerably depending on the material. The Swiss database KBOB (Koordinationskonferenz der Bau- und Liegenschaftsorgane der öffentlichen Bauherren)Official name on kbob.admin.ch: Koordinationskonferenz der Bau- und Liegenschaftsorgane der öffentlichen Bauherren — the Swiss public-sector building owners' coordination conference.Confédération suisse — kbob.admin.ch — Conférence de coordination des services de la construction et des immeubles des maîtres d'ouvrage publics KBOB publishes the reference values used in all regulatory calculations in Switzerland. The chart below compares the embodied energy of typical constructions per m² of energy reference area (SRE)The RECMC and standard SIA 390/1:2025 relate limit values to the energy reference area (SRE), expressed in kg CO₂-eq/m²/yr.République et canton de Genève — Recueil systématique (silgeneve.ch) — Règlement concernant l'empreinte carbone des matériaux de construction (RECMC), rsGE L 5 05.05.
Construction embodied carbon (kg CO₂-eq/m²·an) shown as the primary value, embodied energy (MJ/m²·an) alongside. Indicative values, annualised over 60 years, modules A1–A5 + B4, per m² SRE. The series is calibrated on the Minergie-ECO limit values for new build (25.0–36.1 kWh/m²·an, i.e. 90–130 MJ/m²·an), the 42 kWh/m²·an measured by the SFOE and the ecobau / SIA 390/1 benchmarks (new housing: timber 6, massive 8 kg CO₂-eq/m²·an).
Three material levers stand out systematically: the structure (concrete vs wood), insulation (synthetic vs mineral vs bio-based) and the façade cladding (aluminium or zinc vs render or wood). According to the SFOE, the structural shell accounts for about one third of embodied energySFOE, guide to embodied energy in new buildings: split by CFC groups — structural shell about one third, building services about one fifth, interior fit-out about one fifth.Office fédéral de l'énergie (OFEN) / SuisseEnergie — L'énergie grise dans les nouveaux bâtiments — Guide pour les professionnels, with building services and interior fit-out about one fifth each: structure and envelope are the first lever, but building services cannot be ignored.
The canton of Geneva has embedded, in its loi sur les constructions et les installations diverses (Buildings and Miscellaneous Installations Act, LCI, of 14 April 1988, rsGE L 5 05)Official title cited in the RECMC preamble: "loi sur les constructions et les installations diverses, du 14 avril 1988" (LCI, rsGE L 5 05), art. 117 and 118.République et canton de Genève — Recueil systématique (silgeneve.ch) — Règlement concernant l'empreinte carbone des matériaux de construction (RECMC), rsGE L 5 05.05, requirements that go beyond mere operational energy performance. Articles 117 and 118 form a complementary pair: one sets the rule for material selection, the other the method for measuring their carbon impact.
Calculating embodied energy rests on three complementary pillars: a methodological technical guideline (SIA 2032), a database of material values (KBOB), and software tools that combine the two.
Unlike operational energy, embodied energy cannot be offset after the fact: it is committed at the time of construction. Structuring decisions must therefore be made upstream, from the earliest sketches.
Solid wood (CLT, glulam), cellulose fibre, hemp, straw, rammed earth, raw earth bricks: these materials have embodied energy 3 to 10 times lower than their conventional equivalents. Wood also stores atmospheric carbon (sink effect). Local geo-sourced materials (stone, earth) eliminate transport energy.
Reusing an existing beam or a concrete slab eliminates almost all of the manufacturing embodied energy — only transport and refurbishment are counted. Structural reuse (floors, framing, façades) is one of the most powerful levers, still underused in French-speaking Switzerland but growing fast.
Less material means less embodied energy. A compact form reduces envelope surface area. A structure sized precisely (accurate structural calculation, optimised sections) avoids over-consumption of concrete or steel. The principle of "building lean" is the first embodied-energy move, even before the choice of materials.
A durable material is replaced only once over 60 years instead of two or three — proportionally reducing its B4 impact. Moreover, a "demountable" design (mechanical fixings rather than adhesives, reversible assemblies) enables future reuse of components: this is circular architecture in practice.
Transport (module A4) weighs far less than material manufacturing, but remains a lever that can be acted on. Favouring certified regional timber (FSC/PEFC), insulation manufactured in Switzerland or neighbouring France, and local aggregates reduces this impact while supporting local supply chains — an argument increasingly valued in Geneva's public tenders.
Only certain labels go beyond operational energy performance to include embodied energy and the carbon balance of materials. The table below summarises the main certifications available in French-speaking Switzerland and neighbouring France.
| Label | Embodied energy required | Standard / method | Remark |
|---|---|---|---|
| Minergie®-ECO | ✓ Yes | SIA 2032 + KBOB | The complementary ECO module requires an embodied energy calculation and health/materials criteria |
| Passivhaus Classic/Plus/Premium | — No (Classic) ◐ Partial (Plus/Premium) |
PHPP (renewable energy) | Passivhaus Plus/Premium includes renewable energy generation but not materials LCA as standard |
| SNBS | ✓ Yes — required | SIA 2032 + ecoinvent | "Construction materials" criterion with a maximum GWP and embodied energy threshold; required by some public clients in French-speaking Switzerland, to be checked case by case |
| DGNB | ✓ Yes — central | EN 15978 + ÖKOBAUDAT / KBOB | Full LCA (A–D) weighted into the overall score. One of the most demanding systems on this criterion. |
| Minergie® Standard | — No | — | Operational energy only. The Minergie + ECO combination is needed to include embodied energy. |
| HPE / THPE (Geneva) | ◐ via LCI art. 117–118 | SIA 390/1 / KBOB | HPE/THPE (REn art. 12B/12C — rsGE L 2 30.01) cover only operational energyHPE (REn art. 12B) and THPE (REn art. 12C) standards, rsGE L 2 30.01: they address operational energy performance, independently of LCI art. 117-118.République et canton de Genève — Recueil systématique (silgeneve.ch) — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn), du 31 août 1988. The embodied carbon of materials falls under LCI art. 117–118, which apply regardless of the target level. |
| RE2020 (France) | ✓ Yes — Ic construction | Dynamic regulatory LCA (order of 4 August 2021) | Ic construction indicator (kg CO₂-eq/m², cumulative over the 50-year reference study period)RE2020 guide (Jan. 2024): Ic construction is expressed in kg CO₂-eq/m² over the 50-year reference study period — 740 kg/m² for collective housing at the 2022 milestone, 490 kg/m² from 2031.Ministère de la Transition écologique et de la Cohésion des territoires — Guide RE2020 — Réglementation environnementale des bâtiments neufs (version janvier 2024) with a decreasing threshold per regulatory milestones 2022–2031 |
◐ = partial or incentive-based coverage. — = not required by the base standard.
Is embodied energy mandatory in Geneva?
Yes, progressively. LCI art. 117 requires limiting the embodied carbon of materials — with priority to reuse, then to recycled materials — and art. 118 defines the method: a balance of greenhouse gas emissions over the entire life cycle. Quantitative thresholds have been set since the RECMC (rsGE L 5 05.05, of 15 October 2025)RECMC (rsGE L 5 05.05): low-carbon concept mandatory from 2029, limit values applying to State buildings from 2027 and to all projects from 2034.République et canton de Genève — Recueil systématique (silgeneve.ch) — Règlement concernant l'empreinte carbone des matériaux de construction (RECMC), rsGE L 5 05.05: 5 kg CO₂-eq/m²/yr for renovation, 11.3 for new housing, 12.6 for administration, schools, retail and restaurants — binding from 2027 for State buildings, low-carbon concept from 2029, limit values for all from 2034. For public buildings and projects of a certain scale, a formal LCA is expected. Integrating this criterion from the design stage is both a progressively binding legal requirement and good professional practice.
Does building with wood cost more?
Timber construction often carries a cost premium on the structural shell compared with conventional concrete — but this gap is shrinking as the supply chain industrialises and thanks to site-level gains (speed, dry installation). Over the whole-life cost (LCC), wood is often competitive, notably through reduced construction waste and the preserved value of components at end of life.
Can concrete be kept while still reducing embodied energy?
Yes, several levers exist: low-clinker concrete (cement substituted with fly ash or blast furnace slag), recycled concrete for certain applications, optimised structural sections, and offsetting through the choice of bio-based insulation and low-embodied-energy finishes. An optimised concrete structure can come down to ~110 MJ/m²·an, close to a standard timber buildingConsistent with the Minergie-ECO limit values for new build (25.0–36.1 kWh/m²ERA·yr, i.e. 90–130 MJ/m²·yr) and with the 42 kWh/m²·yr measured by the SFOE.Minergie Suisse — Berechnung der Grauen Energie und der Treibhausgasemissionen bei Minergie-ECO (v1.3).
At what project phase should this be addressed?
Embodied energy is essentially "won" or "lost" during the preliminary studies (EP) and preliminary design (APD) phases. A quick estimate based on a massing and a construction system is enough to guide the major choices. Waiting until the execution file to think about it means it is no longer possible to act on the decisions that really matter.
How can embodied energy be integrated into an architecture competition?
An increasing number of competitions in Geneva and Vaud include an embodied energy / carbon balance criterion in their brief. A schematic per-m² estimate (volumetric ratio based on the intended construction system) is enough at competition stage to position the project. KBOB values by construction system allow a quick comparison between variants without detailed modelling.
Every figure and every claim in this dossier links back to its source. Hover or tap a footnote marker to see it.
Preliminary LCA estimate, material choices, reuse, LCI art. 117–118 compliance — let's talk about it from the sketch phase.
Get in touch