The cantonal building energy certificate rates the envelope and overall efficiency separately on an A–G scale. That distinction changes everything: for reading a property, for accessing subsidies, for proving HPE or THPE equivalence under Geneva law — and for knowing whether you may still replace your fossil-fuel boiler with another fossil-fuel boiler.
The CECB does not award a single grade. It gives two labels on a scale from A (excellent) to G (very poor), for two distinct realities of the same building. The rating reads as Envelope / Overall efficiency.
Thermal quality of the construction — insulation, windows, thermal bridges. Calculated from the theoretical heating demand under SIA 380/1:2016Geneva's REn anchors all its equivalences in « the SIA 380/1 standard, 2016 edition, for heating demand » (art. 12B para. 2 let. a, art. 12C para. 2 let. a).République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn), using standard occupancy and climate conditions.
This is the grade of the « shell » — what you cannot replace cheaply. It reflects the building's real asset value, independent of its occupants.
Efficiency of the overall energy system — heating, domestic hot water, ventilation, lighting, share of renewables.
This is the grade of the « systems » — quicker to improve. Simply replacing a boiler or adding solar thermal can move this grade from E to B or C.
A building rated E/C has a mediocre envelope but decent systems — often a 1970s or 1980s block with a recent boiler. A building rated B/E has a good envelope but an ageing heating system. Reading the two together immediately points the strategy: act on the envelope, on the systems, or on both.
The calculation is performed by certifiers accredited by the cantons, using software certified by the EnDK (Conference of Cantonal Energy Directors). A CECB is in principle valid for ten years, unless major works are carried out.Source to be established — unverified figure. The period of validity is set by the EnDK's CECB regulation, which was not consulted during this pass.Source to be established — unverified figure
In Geneva the CECB is not a recommendation — it is required at several key moments in a building's life. The energy act (LEn, L 2 30) and its implementing regulation (REn, L 2 30.01) define the scope.
FranceThe French equivalent is the DPE (Diagnostic de Performance Énergétique), compulsory on sale and letting. Unlike the CECB, the DPE gives a single A–G grade combining energy demand and CO₂ emissions — without distinguishing envelope from systems. The calculation method (3CL-2021) differs from SIA 380/1:2016.Source to be established — unverified figure. The order setting out the 3CL-DPE 2021 method was not opened during this pass.Source to be established — unverified figure The two tools are not directly comparable.
The CECB is calculated. The IDC is measured. Both speak of energy, but they do not measure the same thing under the same conditions. Understanding the gap avoids misunderstandings with owners — and sometimes reveals significant anomalies.
| Parameter | CECB (calculated) | IDC (measured) |
|---|---|---|
| Nature | Theoretical calculation, SIA 380/1:2016 | Actual consumption read from meters |
| Climate conditions | Standard conditions (reference DRY) | Actual climate of the measurement year |
| Occupancy | Standard SIA occupancy rate | Actual occupancy of the dwellings |
| Behaviour | Fixed set-point temperature (20 °C), standard schedules | Actual behaviour (heating more or less, holidays…) |
| Reference area | ERA (energy reference area) | ERA or cadastral area, depending on the source |
| Main use | Certification, subsidies, comparison between buildings | Monitoring Geneva's legal obligations (REn art. 14)ge.ch, legal bases on the IDC page: LEn art. 6 para. 8 and art. 15C, REn art. 14 and 14A. Art. 14 sets the threshold, the significant-exceedance steps and the deadlines for the audit and the works.République et canton de Genève — OCEN — Que faire selon le résultat IDC de votre immeuble |
A block rated CECB class E may show a measured IDC below the 125 kWh/(m²·yr) (450 MJ/m²·yr) threshold if the occupants are frugal or the flats under-occupied. This is common in Geneva buildings from 1980–2000: the envelope is mediocre, but the IDC remains acceptable. Beware the rebound effect: a renovation that improves comfort can push actual consumption back up if occupants make use of the heat now available.
A measured IDC higher than the calculated CECB often reveals an operational problem: faulty controls, over-ventilation, distribution network losses, or non-residential consumption included in the bill. Such anomalies show up when the CECB and IDC are set side by side.
In Geneva, reaching the HPE or THPE standards does not necessarily require Minergie certification. The CECB Plus — with the corresponding target classes — is an alternative route recognised by the energy act (LEn, L 2 30) and its implementing regulation (REn, L 2 30.01).
| Geneva standard | Situation | Minergie route | CECB Plus route | Legal source |
|---|---|---|---|---|
| HPE | New build | Minergie® | B/B | REn art. 12B paras. 1 and 2 let. bREn art. 12B para. 1: new buildings « holding the Minergie(r) label or any equivalent label ». Para. 2 let. b: « obtaining energy class B/B under the […] CECB Plus ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) |
| HPE | Renovation | Minergie® Renovation | C/B | REn art. 12B paras. 4 and 5 let. bREn art. 12B para. 4: renovated buildings « holding the Minergie(r)Renovation label ». Para. 5 let. b: « obtaining energy class C/B under the CECB Plus ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) |
| THPE | New build | Minergie®-A or Minergie®-P-EcoREn art. 12C para. 1: new buildings « holding the Minergie(r)A or Minergie(r)P-Eco label or any equivalent label ». Para. 2 let. b: class A/A on the CECB Plus.République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) | A/A | REn art. 12C paras. 1 and 2 let. b |
| THPE | Renovation | Minergie®-A or Minergie®-P | B/A | REn art. 12C paras. 3 and 4 let. bREn art. 12C para. 3: renovated buildings « holding the Minergie(r)A or Minergie(r)P label or any equivalent label ». Para. 4 let. b: class B/A on the CECB Plus.République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) |
Values taken from the text of the REn in force (L 2 30.01), art. 12B for HPE and art. 12C for THPE, accessed 24 August 2026. Floor-area ratio bonus, LCI art. 59: HPE → 27.5 %LCI art. 59 para. 1: floor-area ratio of 25 % in zone 5, raised to 27.5 % for an HPE building and 30 % for a THPE building, including for renovated or extended buildings.République et canton de Genève — rsGE L 5 05 — Loi sur les constructions et les installations diverses (LCI), art. 59 (against 25 % standard), THPE → 30 %.
The basic CECB gives a label. The CECB Plus goes further: it produces an advisory report that structures thinking about the renovation. For many owners it is the first document that turns the building's condition into a roadmap — and the starting point for weighing the standards against one another.
The CECB Plus advisory report is rarely enough to start works — it is too general to size the individual trades. Its real value is to create common ground between the owner and the professional appointed: shared objectives, validated stages, a budget anchored in an official document. It is often on the basis of a CECB Plus that the decision to launch a renovation is taken.
The CECB class directly determines whether a fossil-fuel installation may be renewed at the end of its life. The CECB has become a tool that establishes rights — and obligations. In Geneva this regime applies to applications filed since 1 September 2022Legal commentary by MLL Legal: the REn amendment adopted on 13 April 2022 « applies only to building and energy permit applications filed from 1 September 2022 » (art. 30 REn).MLL Legal (commentaire juridique) — Nouveau règlement genevois sur l'énergie : principales modifications, the date the revised REn took effect.
In the wake of the cantonal model energy provisions (MoPEC 2014), most Swiss cantons have introduced the following rule: any replacement of a fossil-fuel heating installation (oil, natural gas) must give preference to a renewable solution. A way out exists where the building reaches CECB class D or better. Watch the detail that matters: in Geneva the REn targets class D foroverall energy efficiency (art. 13N para. 4 let. a) — not for the envelope. The canton of Valais, often cited, also uses overall efficiency.
| CECB class — overall energy efficiency | Replacement obligation | Practical consequence |
|---|---|---|
| A · B · C · D | Exemption possible | The building performs well enough: a condensing installation supplying the building at low temperature may be authorisedREn art. 13N para. 4 let. a: a condensing installation « supplying at low temperature a building whose overall energy efficiency is class D under the cantonal building energy certificate ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn), provided the technical impossibility or economic disproportion of a renewable solution is demonstrated. |
| E · F · G | Renewable required | In practice the renewable option prevails (heat pump, district heating, solar thermal, wood…), unless 30 % renewable production is incorporatedREn art. 13N para. 4 let. b: a condensing installation at low temperature in a building meeting at least SIA 380/1, 1988 edition, « and incorporating renewable energy production covering 30% of overall heat demand ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) into a building meeting at least SIA 380/1, 1988 edition. |
In Geneva, any installation or replacement of a fossil-fuel heat generator ≥ 5 kW thermal subject to a permit (REn art. 13N para. 1)REn art. 13N para. 1: the installation, replacement or conversion of a fossil-fuel installation « requires an energy permit under article 13D from a total nominal thermal output of 5 kW ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn). Replacing a burner 20 years old or more counts as a conversion requiring a permit (REn art. 13M para. 3)REn art. 13M para. 3: « Changing the burner or any other ancillary component of a heat generator 20 years old or more is equivalent to converting an installation within the meaning of article 21 paragraph 2 of the act ».République et canton de Genève — rsGE L 2 30.01 — Règlement d'application de la loi sur l'énergie (REn) — which lowers the bar considerably: almost every boiler in an apartment block is concerned.
SIG's district heating network serves a growing share of Geneva's urban fabric. Connection to it counts as an eligible renewable solution — and may attract SIG grants. Check the availability of the district heating network before considering any other scenario.
Sources: REn L 2 30.01 art. 13M and 13N and LEn L 2 30 art. 21, text in force, accessed 24 August 2026. The Valais rule applicable from 1 January 2025, often quoted as if it applied everywhere, is specific to Valais.
Is the CECB class the same thing as the French DPE label?
No. The DPE gives a single A–G grade combining energy demand and CO₂ emissions, calculated using the 3CL-2021 method. The CECB gives two separate labels (envelope / overall efficiency), calculated under SIA 380/1:2016. The CECB's envelope/systems distinction allows a finer reading of renovation priorities. The two tools are not directly convertible.
My building has a CECB envelope rating of C and an overall efficiency of E — how should I read that gap?
A C/E indicates an envelope in relatively decent condition — built or partly renovated — but inefficient or fossil-fuelled systems. It is typically a 1990s–2000s block with partial external insulation and an ageing gas boiler. The priority is clear: improve the heating system (heat pump, district heating, solar). That single move can lift efficiency from E to B or C without touching the envelope — and it is exactly the HPE renovation scenario (C/B) under Geneva's REn.
Can a gas boiler still be replaced by another gas boiler?
In most Swiss cantons applying MoPEC 2014, no — unless the building reaches CECB class D or better for overall energy efficiency. In Geneva, any replacement of 5 kW thermal or more requires an energy permit from the OCEN, and the permit is granted only if the applicant provesLEn art. 21 para. 3: the permit for a fossil-fuel installation « is granted only if the applicant provides proof » that neither renewable energy nor waste heat can reasonably cover the demand.République et canton de Genève — rsGE L 2 30 — Loi sur l'énergie (LEn) that no renewable energy or waste heat can reasonably cover the demand (REn art. 13N; LEn art. 21 para. 3). Always recommend consulting the OCEN or an energy consultancy before committing, whatever the CECB class shown.
My measured IDC is much better than the CECB predicts — is the certificate still useful?
Yes, for three reasons independent of occupant behaviour. First, the CECB governs access to subsidies and HPE/THPE recognition — the administration does not rely on the measured IDC. Second, it assesses the asset value of the envelope, independent of the current occupants. Third, it determines whether the boiler replacement rules apply — the measured IDC is not the criterion used for that rule.
Is a CECB Plus enough to access Buildings Programme subsidies?
It is required but not sufficient on its own. The Buildings Programme requires a CECB Plus before and after the works to document the class gain. The corresponding Geneva grant (measure M-10) runs from CHF 60.– to CHF 390.– per m² of energy reference area depending on use and the number of classes gained2026 rate schedule, sheet M-10: single-family 150/230/390 CHF/m² ERA, multi-family 90/140/210, other uses 60/90/150, for +2, +3, +4 or more classes.République et canton de Genève — OCEN — Barème des subventions GEnergie 2026, applicable dès le 1er février 2026, and is paid after the result has been checked. The amount is set by whichever label improves the least.2026 rate schedule, sheet M-10: « The energy label showing the smallest improvement determines the amount awarded (Building envelope label and Overall energy efficiency label) ».République et canton de Genève — OCEN — Barème des subventions GEnergie 2026, applicable dès le 1er février 2026 The procedure — pre-notification, validation, execution, inspection — must be started before the works begin. For buildings reaching HPE-Réno (CECB Plus C/B) or THPE-Réno (B/A), measures M-11 to M-13 apply instead, and cannot be combined with M-102026 rate schedule: M-11 HPE and THPE renovation, MoPEC variant; M-12 Minergie variant; M-13 CECB variant (HPE-Réno C/B, THPE-Réno B/A). M-10 is « not combinable with M-01 to M-09, M-11 to M-13 ».République et canton de Genève — OCEN — Barème des subventions GEnergie 2026, applicable dès le 1er février 2026.
Every figure and every claim in this dossier links back to its source. Hover or tap a footnote marker to see it.
A CECB Plus provides the diagnosis — the renovation plan sets the path. Advice and arbitration between the HPE and THPE standards: sequencing the works, technical coherence of the envelope, conditions for accessing subsidies. Geneva, French-speaking Switzerland, neighbouring France.
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