The "Minergie-P Uw of 0.80" circulates on quotations. It appears in no set of rules. The legal minimum for a replaced window is read from an SIA 380/1 limit value; the standards above it are judged on the whole building. This dossier reads the texts one by one — Geneva, French-speaking Switzerland, neighbouring France — and then the grants. The technical choice is covered in Window replacement: the position in the wall matters more than the glazing.
For a window justified component by component, the legal minimum comes down to one value: Uw ≤ 1.0 W/(m²K) against the outside is the SIA 380/1:2016 limit value, in new build as in refurbishmentge.ch, "Assainissement énergétique des fenêtres": replaced windows must meet the element requirements of SIA 380/1, "soit maximum 1 W/m².K".République et canton de Genève — Assainissement énergétique des fenêtres. RCI art. 56 refers to the SIA 380/1 in force; MoPEC 2014 takes up the same value. The other route, the whole-building route, sets no value per window: it judges the heating demand of the building (§ 03). MoPEC is the cantons' model energy prescriptions, a common base adopted canton by canton — not a federal law.
The standards above that minimum — HPE, Minergie — are judged on the whole building, not component by component. In refurbishment the target is also set as a CECB class — the cantonal building energy certificate, a grade calculated from the building rather than a metered consumption.
The RCI (implementing regulation of the law on constructions and various installations, rsGE L 5 05.01) contains, in its article 56A headedrsGE L 5 05.01: the implementing regulation of the LCI is abbreviated RCI. Its art. 56A, "Isolation des embrasures en façade", covers "vitrages, cadres de fenêtres, caissons de stores, etc.". "RALI" does not exist.rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A "Isolation des embrasures en façade" (insulation of "embrasures" in the façade), energy requirements specific to glazing, window frames and blind boxes. The article extends RCI art. 56, which requires the thermal quality of the envelope to comply with the SIA 380/1 standardRCI art. 56: "La qualité thermique de l'enveloppe du bâtiment doit, sauf cas particulier, être conforme à la norme SIA 380/1 en vigueur".rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A in force. By "embrasure" the article means the window assembly itself — "vitrages, cadres de fenêtres, caissons de stores, etc." (glazing, window frames, blind boxes, etc.) —, not the masonry return around the opening, which the technical dossier calls the reveal.
Paragraph 1 covers new buildings. Paragraph 2 is the one that concerns refurbishment. The "embrasures" of an existing building that give onto heated rooms must be brought into compliance as soon as their thermal transmittance U reaches or exceeds 3.0 W/(m²K)RCI art. 56A para. 2: reveals giving onto heated rooms are to be brought into compliance "lorsque leur coefficient de transmission thermique U est égal ou dépasse 3,0 W/(m2 K)", by 31 January 2016 at the latest.rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A. The aim is to meet the energy requirements applicable to refurbishment — SIA 180 and SIA 380/1 — and the sound reduction index of SIA 181. For thermal insulation, that work was to be carried out by 31 January 2016 at the latest. Paragraph 3 refers to SIA 180 for airtightness.
Any single-glazed window exceeds that 3.0 W/(m²K) threshold — a single pane alone sits at U ≈ 5.8 W/(m²K). The article targets first of all the stock still fitted with original joinery. A window replacement that leaves the masonry reveal bare therefore does not breach article 56A, which does not cover that reveal. It does, however, leave a thermal bridge that SIA 380/1 recommends remedying (§ 03), and it opens the condensation risk described in the technical dossier, § 05.
In Geneva, joinery on buildings that are listed, entered in the inventory of buildings worthy of protectionRCI art. 56A para. 4 let. b: buildings that are listed, entered in the inventory of buildings worthy of protection and/or covered by a site plan, within the meaning of the LPMNS.rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A, or covered by a site plan under the LPMNS, like that of buildings in a protected zone, comes under paragraphs 4 and 5: this is the heritage regime. Compliance work there is carried out in the original materials; profile dimensions and glazing subdivisions respect the architecture of the building. RCI art. 56A para. 5 allows four exceptions to the energy requirements for themRCI art. 56A para. 5 let. a: "le remplacement du seul vitrage par un vitrage dont le coefficient d'isolation thermique est égal ou inférieur à 1,0 W/(m2 K), lorsque la menuiserie ou la serrurerie sont conservées".rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A, including replacing the glazing alone with glazing at U ≤ 1.0 W/(m²K) while keeping the existing joinery. The four exceptions allowed:
Double glazing at Ug ≤ 1.0 W/(m²K), warm edge and a profiled timber frame matching the original appearance may therefore be the route to examine. Paragraph 6 further allows waivers where the requirements are disproportionate. They are granted on written request by the office responsible for energy (OCEN), by administrative decision within 3 months and after consultation of the servicesRCI art. 56A para. 6: waivers "sont accordées sur demande écrite par l'office chargé de l'énergie, par voie de décision administrative, dans un délai de 3 mois, sur préavis des services concernés".rsGE L 5 05.01, silgeneve.ch — RCI — Règlement d'application de la loi sur les constructions et les installations diverses, art. 56 et 56A concerned. A waiver has to be applied for; it is never assumed.
HPE — haute performance énergétique (high energy performance) — and, above it, THPE — très haute performance énergétique (very high energy performance) — are two statutory Geneva standards, not labels. The HPE standard of REn art. 12B is not the same thing as Minergie®REn art. 12B: Minergie® label or equivalent (paras 1, 4); otherwise non-fossil heat and: new build MoPEC 2014 + SIA 380/1, CECB® B/B or 80% SIA 380/1 (para. 2); refurbishment, MoPEC +70%, SIA +50% or CECB® C/B (para. 5).rsGE L 2 30.01, silgeneve.ch — REn — Règlement d'application de la loi sur l'énergie, art. 12B et 12C: the label is only one of the admitted routes. The other route requires a main heat supply that is non-fossil and local, or a heat network that is so for at least 50%. In new build it offers three variants: compliance with the MoPEC 2014 and SIA 380/1:2016 limit values, the CECB® B/B class, or 80% of the SIA 380/1 limit values for heating. In refurbishment the label is Minergie® Rénovation, and the variants are the MoPEC 2014 limit values raised by 70% together with those of SIA 380/1 raised by 50%, or the CECB® C/B class. All of them are assessed on the overall energy balance of the building, not component by component.
The window weighs in that balance through its Uw and through the thermal bridges of its installation. The SIA 380/1 calculation includes linear thermal bridges: a high ψinstallation — the thermal bridge at the junction between window and wall — across all the windows can tip an HPE balance below target. The worked example is in the technical dossier, § 03.
In the fifth zone, the floor area ratio of LCI art. 59 para. 1 — 25%, raised to 27.5% for high energy performance and to 30%LCI art. 59 para. 1: the area "peut être portée à 27,5% lorsque la construction est conforme à un standard de haute performance énergétique, respectivement à 30%". It is para. 1, not para. 4.rsGE L 5 05, silgeneve.ch — LCI — Loi sur les constructions et les installations diverses, art. 59 al. 1 for very high energy performance, renovated or extended buildings included — follows the same logic. That bonus depends on the standard the building reaches, not on the windows alone. Para. 4 is a separate regime, reserved for areas of increased densification, and it raises the THPE figure only. Weighing up those variants before ordering the windows is precisely what advice is for.
In Geneva, LCI art. 114A para. 3 provides that the thickness of external insulation counts neither towards the building envelope limits nor towards the distancesLCI art. 114A para. 3: "l'épaisseur de cette isolation n'est pas prise en compte, ni dans le calcul du gabarit, ni dans celui des distances aux limites de propriété ou entre constructions".rsGE L 5 05, silgeneve.ch — LCI, art. 114A — Isolation périphérique de constructions existantes to property boundaries or between buildings. This makes outboard installation followed by external insulation easier: the thickness of the insulant burdens neither the envelope limits nor the boundary distances. The article says nothing about the projection of the window itself. Watch para. 2 however: the exclusion from the floor area ratio granted by para. 1 falls awayLCI art. 114A para. 2: para. 1 “n'est pas applicable si les constructions bénéficient de rapports de surface augmentés en raison de la reconnaissance de la haute performance énergétique selon l'article 59, al. 1 et 4”.rsGE L 5 05, silgeneve.ch — LCI, art. 114A — Isolation périphérique de constructions existantes if the building already claims the HPE/THPE bonus of art. 59. Check with the building permit office (OAC)ge.ch: the OAC, part of the territorial department, processes and decides building permit applications. The OCBA is the cantonal buildings office — a client body, not a permitting authority.République et canton de Genève, département du territoire — Office des autorisations de construire (OAC) whether the building is in a protected zone, or whether the projection alters the appearance of the façade. Outboard installation itself is described in the technical dossier, § 04.
The Minergie label regulations set no Uw or Ug value per component: the window is judged by the overall balance and by the airtightness of the envelopeMinergie label regulations 2026.1: no numerical Uw or Ug requirement per component, not even for Minergie-P in refurbishment. The page claimed "installed Uw ≤ 0.80 for Minergie-P": that value is not there.Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.1. That airtightness is measured to SIA 180:2014 and ISO 9972:2015, with qE50 ≤ 0.8 m³/(h·m²) in new build and ≤ 1.6 in refurbishmentMinergie regulations 2026.1, § 6.2 "Airtightness of the envelope". The regulations cite SN EN ISO 9972:2022; the edition retained on this site remains ISO 9972:2015 with SIA 180:2014.Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.1 for Minergie-P and Minergie-A. The "Minergie-P Uw of 0.80" that circulates on quotations appears nowhere in the regulations. The choice of glazing, frame and spacer is therefore made within that balance, not on a catalogue value.
The other French-speaking cantons apply their own regulations derived from MoPEC — Neuchâtel, for instance, bases its application guide on SIA 380/1:2016EN-NE102, April 2023 edition, “Base: norme SIA 380/1, édition 2016”. § 6.2: in alterations SIA 380/1 (§ 2.2.3.6) recommends remedying thermal bridges; no limit value under the single-component route.Service de l'énergie et de l'environnement, canton de Neuchâtel — Aide à l'application EN-NE102 — Isolation thermique des bâtiments (SIA 380/1, édition 2016), édition avril 2023. MoPEC 2025 was adopted by the Conference of Cantonal Energy Directors on 29 August 2025EnDK, statement of 29 August 2025: the plenary assembly adopts the 2025 model energy provisions. These are recommendations to the cantons, in force only once transposed into cantonal law.EnDK — Conférence des directeurs cantonaux de l'énergie — Les cantons adoptent le Modèle de prescriptions énergétiques 2025 and still has to be transposed canton by canton. Reveal insulation is not always spelled out there in an article equivalent to Geneva's RCI art. 56A. Nor does the limit value U ≤ 1.0 W/(m²K) for windows impose it: it applies to the window alone, at standard size.
In alterations, SIA 380/1 merely recommends remedying the adjacent thermal bridges, with no limit value under the single-component route. They must, however, be included under the whole-building route, as in a Minergie file.
RE2020 sets whole-building performance requirements without imposing a minimum Uw on windows. The BBC Effinergie Rénovation 2024 label also reasons at building level. In housing it requires label A or B of the DPE — diagnostic de performance énergétique, the French energy certificate issued on sale and on letting. At the "première étape" (first stage) step, it is label C. For a complete renovation it also requires a measured air permeability Q4Pa-surf ≤ 1.20 m³/(h·m²)Effinergie guide 26.06.2024: DPE A or B (< 110 kWhEP, < 11 kgCO₂eq/m²·yr); first stage: C (< 180, < 30), airtightness test with no threshold, Uw ≤ 1.3. Complete renovation: Q4Pa-surf ≤ 1.20 m³/(h·m²).Collectif Effinergie — Guide d'application du label BBC Effinergie rénovation (arrêté du 3 octobre 2023). For windows replaced in a first stage of works, the application guide sets Uw ≤ 1.3 W/(m²K).
In France, DTU 36.5 (external joinery) governs the installation of windowsNF DTU 36.5 P1-1, "Travaux de bâtiment — Mise en œuvre des fenêtres et portes extérieures — Cahier des clauses techniques types", April 2010: new build and refurbishment, fixed on at least two opposite sides.AFNOR / Norm'Info — NF DTU 36.5 P1-1 — Travaux de bâtiment — Mise en œuvre des fenêtres et portes extérieures — Cahier des clauses techniques types. Reveal insulation is not systematically imposed by the DTU alone. The BBC Effinergie Rénovation 2024 guide, for its part, notes that the 3CL-DPE method does not capture every thermal bridge and asks for particular attention to them. A description of the thermal bridges and their remedies is presented there as a plus for the projectBBC Effinergie rénovation guide (26.06.2024): the 3CL-DPE method does not allow thermal bridges to be fully accounted for; a description of thermal bridges and remedies “est un plus pour le projet”.Collectif Effinergie — Guide d'application du label BBC Effinergie rénovation (arrêté du 3 octobre 2023), not as a condition of approval.
In Geneva, grants go through a single counter, GEnergie, the cantonal portal for energy grants: the federal Buildings Programme co-finances the cantonal measures and its platform is the submission route. The measure that rewards an envelope refurbishment is M-10, CECB® class improvement. It pays CHF 60 to 390 per m² of energy reference area depending on use and on the number of classes gained, with a minimum of two classesGEnergie, measure M-10: CHF 150 to 390/m² for single-family housing, 90 to 210 for collective housing, 60 to 150 for other uses, minimum "+2 classes". The page said "20 to 30 CHF/m² per year saved".GEnergie, OCEN, République et canton de Genève — Amélioration de la classe CECB® pour l'enveloppe et pour l'efficacité énergétique globale — mesure M-10, on the envelope and on overall energy efficiency.
Are windows alone enough, without external insulation? Yes, provided the two-class gain is reached. But the CECB class improvement is calculated over the whole envelope, not the windows alone: replacing only the windows without touching the opaque elements does not guarantee that gain. It is better to simulate the scenarios before deciding the order of works. The documents to supply and the order of decisions are in the technical dossier, § 06.
Window replacement left the parcours par geste of MaPrimeRénov', the single-measure track, on 1 September 2026: it is now fundable only within a deep renovationDecree no. 2026-822 of 25 August 2026 (JORF no. 0199 of 27 August 2026), art. 4: annex 1 is replaced; the “isolation” grants leave the single-measure route on 1 September 2026, glazed elements included.Légifrance — Journal officiel de la République française — Décret n° 2026-822 du 25 août 2026 modifiant le décret n° 2020-26 du 14 janvier 2020 relatif à la prime de transition énergétique. The parcours par geste funds one isolated measure, with no prior audit and no required gain in classes. The rénovation d'ampleur (deep renovation) is the other route: a coordinated, supervised package of works tied to a gain in DPE classes. Since the rates change several times a year, rely on france-renov.gouv.fr rather than on a copied table.
Every figure and every claim in this dossier links back to its source. Hover or tap a footnote marker to see it.
SIA 380/1 limit values, HPE, Minergie®, EnerPHit: the standard you aim for decides what the window has to bring to the balance. NRG positive advice: a reading of your building and weighing up the standards, for Geneva and French-speaking Switzerland.
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