Published on August 1, 202612 min read · the essentials in 2 minEnerPHit · Minergie-P RetrofitProject strategy · PhasingUpdated June 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 Rénovation 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.
An unrenovated building from the 1960s–1980s frequently exceeds the Geneva thresholds. A large share of the Swiss building stock was built before the first meaningful thermal requirements of the 1980s, without significant insulation — and in Geneva, above 125 kWh/m²·an (450 MJ/m²·an) of heating expenditure indexThreshold set by the Geneva REn (rsGE L 2 30.01, art. 14): above 125 kWh/m²·an (450 MJ/m²·an), an energy audit and improvement measures are required.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 14 et 14Baccessed 2026-08-20, an energy audit becomes mandatory.
A superficial retrofit (replacing windows, a more efficient gas boiler) brings only a marginal improvement. Only a coordinated envelope + systems retrofit can divide heating consumption by a factor of roughly 5 — from the 125 kWh/m²·an of the Geneva audit thresholdFactor derived from two sourced values: the Geneva audit threshold of 125 kWh/m²·an (REn art. 14) and the EnerPHit target of ≤ 25 kWh/(m²a), PHI v10c Tab. 3, cool-temperate — a ratio of about 5.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 down to the ≤ 25 kWh/m²·an targeted by EnerPHit — and achieve lasting thermal comfort.
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.
order of magnitude of the reduction: from the Geneva audit threshold to EnerPHit level
What Geneva law requires of building owners
In Geneva, owners of heated buildings declare their building's IDC — Indice de Dépense de Chaleur (heating expenditure index) to the OCEN each year: the actual heating and domestic hot water consumption, measured at the meters and expressed per unit of reference energy floor area. It is not a theoretical calculation — it is the building's real energy bill. Not to be confused with individual heating-cost accounting, which applies to buildings with at least 5 heat off-takers (REn art. 14B)Two distinct regimes in the Geneva REn: the IDC (art. 14) applies to owners of heated buildings; individual heating-cost accounting (art. 14B) applies from 5 off-takers.République et canton de Genève — Règlement d'application de la loi sur l'énergie (REn), rsGE L 2 30.01, art. 14 et 14Baccessed 2026-08-20: that is a separate rule, unrelated to the scope of the IDC.
This index is no longer just a monitoring tool: it triggers legal obligations for building owners.
the IDC is often expressed in MJ/m²·an: 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 improvement measures after a simple exceedance, 36 months for works after a significant exceedance. That framework is one input to the project among others: it sets a horizon, but it does not determine the performance level to aim for — which is a matter of arbitration between the standards.
Subsidies available in French-speaking Switzerland
The Programme Bâtiments (Confederation + cantons) subsidizes retrofits that reach high performance levels. 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 specific grants, and Minergie®-certified works benefit from a bonus. The owner's-representative (AMO) subsidy was discontinued in 2026. Rates are revised annually and should be checked before any application: leprogrammebatiments.ch or through the SIG-éco21 partners.Official Programme Bâtiments domains: leprogrammebatiments.ch (FR), dasgebaeudeprogramm.ch (DE), ilprogrammaedifici.ch (IT).Confédération suisse et cantons — Le Programme Bâtimentsaccessed 2026-08-20
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 Rénovation
Two main standards define "passive retrofit" in French-speaking Switzerland: EnerPHit (Passivhaus Institut, Darmstadt) and Minergie-P Rénovation. 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·an (PHPP) or a component-based approach (U-values)
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)
Airtightness
qE50 ≤ 1,6 m³/(h·m²) for retrofits
Key feature
Official recognition by the Swiss cantons. Minergie-P applies to new build and retrofit alike: regulation 2026.1 defines no separate "Minergie-P Rénovation" labelChecked against Minergie regulation 2026.1: Minergie-P covers new build and retrofit under a single procedure; neither module certification nor a dedicated procedure for protected buildings appears in it.Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.12026 · accessed 2026-08-20, 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 416). The two requirements are not even of the same kind — EnerPHit sets an absolute value (≤ 25 kWh/m²·an 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, absolute minimum of 15 kWh/m²·an)Minergie regulation 2026.1, sec. 8.1: fossil fuels not allowed for heat generation, with narrow exceptions (peak load ≤ 10 % above 80 kW; district heating ≤ 50 % fossil).Minergie Suisse — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, version 2026.12026 · accessed 2026-08-20.
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 80% 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 audit 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) 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 the certifying body — the Passivhaus Institut for EnerPHit, Minergie Suisse 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 vary enormously depending on the building's initial condition, its geometry, the presence of structural thermal bridges, and the choice of materials: there is no public cost database that would allow a reliable price per m² to be quoted for a retrofit to passive level, and any serious costing requires a quotation on the actual building. What is public and quantified, by contrast, is the support. In Geneva, measure M-13 "HPE retrofit, CECB® variant" pays 390 CHF/m²GEnergie schedule, sheet M-13 "HPE retrofit, CECB® variant": 390 CHF/m² SRE for single-family housing, 210 for collective, 150 for other uses; class C/B under CECB Plus.GEnergie / canton de Genève — HPE — Rénovation variante CECB®, mesure M-13accessed 2026-09-04 of heated floor area for single-family housing and 210 CHF/m² for collective housing; 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 — it is even the most common situation. 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. The rule: start with the roof (the most cost-effective energy-wise), then the façades, then the windows (taking into account their final position within the insulated wall), then the systems. 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 target a similar level of performance and allow a component-based approach. Minergie-P is more widely recognized in the Swiss context, with a well-established cantonal procedure and better integration into subsidy applications. EnerPHit is the Passivhaus Institut's international standard: it is recognized outside Switzerland and its PHPP methodology is very precise. In practice, building owners in Geneva or Vaud will often choose Minergie-P Rénovation for its administrative ease, while EnerPHit will be preferred for projects with strong technical stakes or an exemplary role.
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 a simple exceedance, 36 after a notable one.
Survey before you set the target. Existing U-values, air permeability, 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.
Test airtightness before the build-up is closed. Once the finishes are on, a leak is practically unreachable — and putting it right is out of all proportion.
GenevaThe IDC is declared to the OCEN every year. Above the thresholds an audit and then works are ordered, with 12 and 36 months respectively 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 FranceThere is no French equivalent of the IDC enforceable against an owner. In neighbouring France the performance benchmark is the DPE, and support schemes are national.
Sources and references (17)
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