Published on August 1, 202612 min read · the essentials in 2 minEnerPHit · Minergie-P (retrofit)Project strategy · PhasingUpdated October 2026
Retrofitting in Geneva: standards, strategy and phasing
A high-performance retrofit is decided first in the strategic choices: what level to aim for, in what order to intervene, with which subsidies. This dossier sets out the framework — the EnerPHit and Minergie-P (retrofit) standards, project approach, phasing — and recalls the obligations Geneva law attaches to the heating expenditure index. Implementation — envelope, airtightness, systems — is detailed in the practical dossier.
Older unrenovated buildings are the first to be caught by the Geneva thresholds. In Geneva, above 125 kWh/m²·yr (450 MJ/m²·yr) of heating expenditure indexREn GE art. 14 paras 1, 3, 4 and 8: threshold 125 kWh/m²·yr (450 MJ) on the 3-year average IDC; audit and improvement measures ordered, 12 months; no audit between 125 and 153 if measures suffice.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 14, 14A et 14Baccessed 2026-10-01, averaged over the last 3 years, the department orders an energy audit and improvement measures; no audit is required between 125 and 153 kWh/m²·yr if the measures alone bring the index back below the threshold.
Replacing only the windows or only the heat generator is not enough to reach a passive retrofit standard: EnerPHit and Minergie-P both set requirements on the whole envelope. In Geneva, installing or replacing a fossil-fuel boiler is moreover subject to an energy permit from 5 kW (REn art. 13N para. 1)REn GE art. 13N para. 1: installing, replacing or converting a fossil-fuelled heat generator requires an energy permit from 5 kW. Art. 13M para. 1: priority to renewable energy.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 13M et 13Naccessed 2026-10-01. Only a coordinated envelope + systems retrofit can reach the EnerPHit level — ≤ 25 kWh/m²·yr of heating demand, calculated with PHPPLEn GE art. 6 paras 7-8: the IDC is a measured final-energy index, per SRE and climate-corrected; art. 15C para. 4: heating and DHW. PHI v10c Tab. 3: EnerPHit = calculated heating demand.République et canton de Genève — Loi sur l'énergie (LEn), rsGE L 2 30, art. 6 al. 7-8 et art. 15Caccessed 2026-10-01 — and achieve lasting thermal comfort. That figure does not compare with the Geneva IDC: the IDC is measured final energy consumption for heating and domestic hot water, climate-corrected and expressed per unit of reference energy floor area; EnerPHit sets a calculated demand, for space heating only, on a different reference area. A project's real gain shows in the IDC before and after the works.
Retrofitting to the passive standard does not mean sticking insulation everywhere. It is a comprehensive design approach that treats the existing envelope as a coherent system — with its own constraints and opportunities.
In Geneva, the annual calculation of the IDC — Indice de Dépense de Chaleur (heating expenditure index) is mandatory for all heated buildings (LEn art. 15C para. 1)LEn GE art. 15C para. 1: annual calculation of the heating expenditure index is mandatory for all heated buildings. Para. 3: the owner or their agent submits the data.République et canton de Genève — Loi sur l'énergie (LEn), rsGE L 2 30, art. 6 al. 7-8 et art. 15Caccessed 2026-10-01; the owner or their agent passes the data to the OCEN. The IDC expresses the final energy consumed for heating and domestic hot water, read off the meters, related to the reference energy floor area and corrected for that year's climate. It is not a theoretical calculation: it is measured consumption. Not to be confused with individual heating-cost accounting, which applies to buildings with at least 5 heat off-takers (REn art. 14B)REn GE art. 14B para. 1: individual billing mandatory from 5 users of a central heating plant. Art. 14A para. 7: IDC calculation waived below 5 off-takers, single plant, 3-year average IDC ≤ 125 kWh/m²·yr.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 14, 14A et 14Baccessed 2026-10-01. The 5-off-taker threshold also matters for the IDC, but the other way round: a residential building served by a single heating plant with fewer than 5 heat off-takers is exempt from the calculation as long as its 3-year average IDC stays ≤ 125 kWh/m²·yr (REn art. 14A para. 7).
This index is no longer just a monitoring tool: it triggers legal obligations for building owners.
> 180
kWh/m²·yr (650 MJ/m²·yr): the significant-exceedance threshold, above which remediation works are orderedREn GE art. 14 para. 2: significant exceedance when the 3-year average IDC exceeds 222 kWh/m²·yr (800 MJ) until 31.12.2026, 180 (650 MJ) from 01.01.2027 to 31.12.2030, 153 (550 MJ) from 01.01.2031.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 14, 14A et 14Baccessed 2026-10-01, from 2027 — 3-year average IDC; 222 kWh (800 MJ) until end of 2026, 153 kWh (550 MJ) from 2031
the IDC is often expressed in MJ/m²·yr: 125 kWh ≈ 450 MJ, 180 kWh ≈ 650 MJ
In practical terms, for an owner or a property management firm
The statutory deadlines run from the OCEN's notification: 12 months for the audit and improvement measures after the threshold is exceeded, 36 months for works after a significant exceedance. That framework sets a time horizon for your project; it does not determine the performance level to aim for. The calculation rules and obligations attached to the IDC are set out by the cantonal energy office (OCEN) on ge.ch.
Subsidies available in French-speaking Switzerland
The Programme Bâtiments (Confederation + cantons) subsidizes single measures — insulating one element, replacing the heating system — as well as whole-building retrofits. In Geneva, the 2026 scheme carries CHF 80 million and brings together the DepartmentCanton of Geneva, 2 February 2026: run by the Department of Economy and Employment, the SIG and the Programme Bâtiments; the AMO subsidy expires and is discontinued in 2026.République et canton de Genève — Subventions énergétiques 2026 : 80 millions de francs pour accélérer la rénovation du parc bâti genevois2026-02-02 · accessed 2026-08-20 of Economy and Employment, the Services industriels de Genève and the Confederation's Programme Bâtiments; HPE (high energy performance) and THPE (very high energy performance) retrofits attract grants per m² of reference energy floor area (measures M-11 to M-13), higher for THPE than for HPEGEnergie 2026 schedule, M-11 to M-13: HPE and THPE retrofit grants per m² of SRE, by building use, higher for THPE; M-12 Minergie variant: «Eco» bonus. Amounts: see the schedule.GEnergie / canton de Genève — Subventions énergétiques 2026 — barème GEnergie, applicable dès le 1er février 2026, mesures M-11 à M-132026-02-01 · accessed 2026-10-01; under the Minergie® variant an «Eco» bonus is added for an Eco-certified building. The AMO énergie (AMOén) subsidy was discontinued in 2026. The schedule is published each year on ge-energie.ch; applications are filed before works begin on the leprogrammebatiments.ch platform.Canton of Geneva, 02.02.2026: cantonal subsidy applications must be filed before works begin on leprogrammebatiments.ch; measures and schedule on ge-energie.ch.République et canton de Genève — Subventions énergétiques 2026 : 80 millions de francs pour accélérer la rénovation du parc bâti genevois2026-02-02 · accessed 2026-10-01
Phased retrofit: planning for coherence from the outset
Many retrofits are carried out in several phases (windows one year, façade three years later, roof afterwards). This is often a financial necessity. But without an overall plan, each phase can compromise the next: windows replaced before the ITE will end up in the wrong position and create thermal bridges. The golden rule: design the complete project from the outset, even if execution is phased.
02 — Retrofit standards
EnerPHit and Minergie-P (retrofit)
Two main standards define "passive retrofit" in French-speaking Switzerland: EnerPHit (Passivhaus Institut, Darmstadt) and Minergie-P (retrofit). Their requirements differ in logic, but their shared goal is to reach a performance level close to new passive construction, while accounting for the constraints of the existing building stock.
PASSIVHAUS INSTITUT
EnerPHit
Heating demand
≤ 25 kWh/m²·yr (PHPP) or the component method (opaque envelope, windows, ventilation)
Airtightness
n₅₀ ≤ 1.0 h⁻¹ (vs 0.6 for new Passivhaus)
Heating demand
≤ 90 % of MoPEC 2025 (cantonal model energy regulations) limit valuesMinergie regulation 2026.1, sec. 6.1: retrofit ≤ 90 % of the Qh,li MoPEC 2025 limit values per SIA 380/1:2016; ≤ 70 % for new build.Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.12026 · accessed 2026-08-20 for retrofits (SIA 380/1:2016) (vs ≤ 70% for new Minergie-P — regulation 2026.1)
Key feature
In Geneva, the Minergie-P label opens the statutory THPE standard for retrofits (REn art. 12C para. 3)REn GE art. 12C para. 3: renovated buildings holding the Minergie-A or Minergie-P label, or any equivalent label, count as THPE. EnerPHit is not named.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 12B et 12Caccessed 2026-10-01. Minergie-P applies to new build and retrofit alike: regulation 2026.1 defines no separate "Minergie-P Rénovation" labelMinergie regulation 2026.1: Minergie-P covers new build and retrofit, with no separate label and no module certification. The GEnergie 2026 schedule nonetheless uses the term "Minergie®-P Rénovation".Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.12026 · accessed 2026-10-01, no module-by-module certification and no dedicated procedure for protected buildings — those instruments belong to the Minergie Rénovation products.
Take care when comparing the numerical thresholds: the reference energy floor area (SRE) is not calculated the same way between Passivhaus (PHPP reference floor area, PHI Darmstadt) and Minergie® (SRE per SIA 380:2022REn GE art. 12D para. 5: the reference energy floor area is defined by standard SIA 380, 2022 edition. SIA 416 covers building areas and volumes, not the SRE.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 12D al. 5accessed 2026-10-01). The two requirements are not even of the same kind — EnerPHit sets an absolute value (≤ 25 kWh/m²·yr in a cool-temperate climate), Minergie-P a percentagePHI v10c, Tab. 3: ≤ 25 kWh/(m²a) applies to the cool-temperate zone alone — 35 arctic, 30 cold, 20 warm-temperate, 15 warm. Minergie-P is instead expressed as a % of the MoPEC 2025 limits.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 3 : besoin de chaleur EnerPHit2023-01-20 · accessed 2026-09-04 of the MoPEC 2025 limit values — so that a direct comparison of the figures would make no sense. MoPEC — the cantons' model energy regulations — is the common baseline from which each canton derives its own energy act: it is not a directly applicable federal standard. The two airtightness measures are not comparable either: Passivhaus/EnerPHit measure n₅₀ (air changes per volume), Minergie® measures qE50 (leakage flow rate per envelope surface area, EN ISO 9972:2015 + SIA 180:2014Minergie regulation 2026.1, cl. 6.2, cites "SIA 180:2014 and SN EN ISO 9972:2022 (standard SIA 180.206)"; 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 2026.12026 · accessed 2026-09-04). Minergie® values according to regulation 2026.1 (fossil fuels prohibited, limit value never below 15 kWh/m²·yr)Minergie regulation 2026.1: sec. 6.1, heating demand requirement never below 15 kWh/(m²a); sec. 8.1, fossil fuels excluded, except peak load ≤ 10 % from 80 kW or district heating ≤ 50 % fossil.Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.12026 · accessed 2026-10-01.
Implementation, component by component
Envelope strategy (façades, roof, windows, thermal bridges), airtightness plane, ventilation and heating: the technical detail is covered in a dedicated dossier — Passive retrofit in practice →
03 — Approach and phasing
How to run a passive retrofit project
A passive retrofit cannot be improvised after the fact: decisions made at the design stage determine most of the result. Here is the typical sequence of a well-run project. The detailed-design and site phases — construction junctions, airtightness plan, intermediate tests — are covered in the practical dossier →
Step 1 — Diagnosis
Energy and technical baseline survey
A full thermal survey precedes every decision: survey of existing U-values, measurement of the building's air permeability, infrared imaging in cold weather and mapping of thermal bridges — these measurements are carried out by a specialist firm or a testing contractor. Add to that the identification of any heritage constraints. This diagnosis guides everything: without it, it is impossible to define objectives or cost the works.
Step 2 — Preliminary design
Defining the envelope + systems strategy
Choice of target standard (EnerPHit, Minergie-P, or an intermediate level) and construction system variants per component. Whether the targets are met is checked by a preliminary thermal calculation — PHPP for EnerPHit, SIA 380/1 for Minergie — carried out by the design team or a specialist consultancy. Cost assessment per variant and identification of subsidies, which must be applied for before works begin.
Step 3 — Handover and certification
Final airtightness test, as-built calculation, certification file
A final airtightness test (n₅₀ ≤ 1.0 h⁻¹ for EnerPHit, qE50 ≤ 1.6 m³/(h·m²) for Minergie-P retrofits) is run by the testing contractor, and the PHPP or SIA 380/1 calculation is updated with actual values by the thermal consultancy. The certification file is then assessed by a certifier accredited by the Passivhaus Institut for EnerPHit, or by a Minergie certification office for Minergie-P — and not by the design team. Consumption measurements over the first heating season allow the result to be verified.
04 — Key questions
What building owners ask
How much does a retrofit to the passive standard cost?
Costs depend on the building's initial condition, its geometry, the presence of structural thermal bridges, and the choice of materials: a costing requires a quotation on the actual building. What is public and quantified is the support. In Geneva, measure M-13 "HPE retrofit, CECB® variant" supports retrofits per m² of reference energy floor area (SRE), depending on use and the standard reached — the amounts, like the MoPEC (M-11) and Minergie (M-12) variants, are set out in the GEnergie 2026 scheduleGEnergie 2026 schedule, applicable from 01.02.2026, M-13 CECB® variant: grant per m² of SRE, by building use; HPE retrofit = CECB classes C/B, THPE retrofit = B/A. Amounts: see the schedule.GEnergie / canton de Genève — Subventions énergétiques 2026 — barème GEnergie, applicable dès le 1er février 2026, mesures M-11 à M-132026-02-01 · accessed 2026-10-01; the 2026 cantonal budget amounts to CHF 80 millionCanton of Geneva announcement of 2 February 2026: CHF 80 million in energy subsidies for 2026, CHF 10 million more than in 2025.République et canton de Genève — Subventions énergétiques 2026 : 80 millions de francs pour accélérer la rénovation du parc bâti genevois2026-02-02 · accessed 2026-08-20. Since the rates are revised annually, they should be checked before any application. The return on investment is also measured in comfort, property value, and protection against energy price volatility.
Can a retrofit be done in stages without doing everything at once?
Yes. The key is to design the project as a whole before starting the first phase, to ensure that each intervention is consistent with those that follow. A frequently adopted order: the roof, then the façades, then the windows (taking into account their final position within the insulated wall), and the systems last, once the reduced demand is known. Never replace the windows before deciding on the façade insulation system.
What is the difference between a "Minergie" retrofit and an "EnerPHit" retrofit?
Both standards aim at a high level of performance, but only EnerPHit provides for component-based certification. Minergie-P is anchored in the Swiss framework: in Geneva it gives access to the THPE standard for retrofits (REn art. 12C para. 3) and to a dedicated measure in the cantonal subsidy schedule (M-12). EnerPHit is the Passivhaus Institut's international standard: recognised beyond Switzerland and demonstrated with PHPP, it is not named in the Geneva regulation. The choice therefore depends on the project: Minergie-P fits directly into Geneva's standards and subsidies; EnerPHit makes sense when international certification or a pre-certified step-by-step retrofit is the aim.
Key points
What to remember, and in what order to act
Start by reading your IDC. It tells you whether the law imposes a timetable, and which: 12 months after the threshold is exceeded, 36 after a significant exceedance.
Survey before you set the target. Existing U-values, air permeability (a test to entrust to a specialist contractor), thermography, heritage constraints: without that survey no costing holds.
File the subsidy application before committing to the works. Filing first conditions the grant, and the rates are revised every year.
Design the complete project even if you build it in phases. Windows fitted before the external insulation will end up in the wrong position.
Start with the roof, finish with the systems. Roof, façades, windows, then plant: that order avoids sizing on demands that are already out of date.
Have airtightness tested before the build-up is closed. The test is to be entrusted to a specialist contractor: once the finishes are on, a leak is practically unreachable — and putting it right is out of all proportion.
GenevaThe IDC is calculated every year, with the data passed to the OCEN. Above the threshold an audit and improvement measures are ordered (12 months); above a significant exceedance, works (36 months), from notification.
SwitzerlandThe Buildings Programme, run jointly by the Confederation and the cantons, subsidises high-performance retrofits; budgets and rates remain cantonal and annual.
Neighbouring FranceFor housing, France has no counterpart to the IDC: the benchmark is the DPE, calculated rather than measured. Tertiary buildings of 1,000 m² and more face targets on measured use (CCH art. L174-1). Support is mainly national.
Sources and references (24)
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