Planning a heating replacement in Geneva
This guide summarizes Geneva's rules for replacing oil or gas heating, the question of connecting to a thermal network, the deadlines for cantonal subsidies and what to check in a quote. It does not replace the official pages, which it cites.
1. Geneva's rule: renewable at every replacement
In Geneva, replacing an existing heating system or installing a new one now requires a renewable solution. This is a cantonal rule.
Watch out with old boilers: replacing the burner, the controller or the body of an oil or gas boiler older than 20 years counts as replacing the heating, so the renewable rule applies.
The canton advises starting to consider a replacement once the installation is 10 to 15 years old, rather than waiting for a breakdown.
Fossil heating is still allowed only in rare cases of technical impossibility, which the application must justify. If a boiler breaks down in winter, the cantonal energy office (OCEN) tolerates a temporary fossil solution, but a mainly renewable installation must be in place before the next heating season.
2. Thermal network (RTS): check the map first
The structuring thermal networks (RTS) are built and operated by Services industriels de Genève (SIG), under the canton's supervision. The cantonal map shows whether a building is in an influence zone and from which year connection is possible.
In an influence zone, connection is mandatory when heat production is installed or renewed. Villas and small buildings whose substation is under 50 kW are exempt, but may connect.
In practice, when changing a boiler in an RTS zone, the owner or their firm files SIG's thermal information request (DITH); the answer arrives by e-mail within 30 days at most. File it before comparing heat-pump quotes.
3. Permits and subsidies: the order of steps
Depending on the project, a heating replacement goes through a building permit (building permits office, OAC) or a simplified procedure with OCEN. In principle the contracted firm handles this, and it must appear in its quote.
For a heat pump, the permit or simplified procedure must be validated before work starts, and the unit must meet federal and cantonal noise rules.
Geneva subsidy amounts and conditions are published on the GEnergie site and in the cantonal schedule; some municipalities also fund measures. Some requests go through the Buildings Programme platform, others through the canton's e-services. For a renovation, you choose between the subsidies and the forecast reduction in charges (BPC).
The deadline that matters: OCEN must receive the subsidy request at least 14 days before the related work starts, and the work must be done within 24 months of the decision.
This guide does not say whether a project qualifies for a subsidy: only the conditions published by the canton are authoritative.
4. Preparing the quote request
A written request makes quotes comparable: type, output and age of the current heating, consumption over recent years, heated area, position relative to the RTS zone, the DITH answer if you have it, photos of the boiler room and your preferred period.
For an apartment building, the owner calculates and submits the heat expenditure index (IDC) to OCEN every year; above 125 kWh/m² per year an energy upgrade is required. For a villa or small residential building, the calculation is optional for now. Attaching the latest IDC to a quote request helps the firm size the installation.
5. Reading a quote without being rushed
The canton reports pushy door-to-door selling, especially for heat pumps. Its advice: do not sign on the spot, avoid large deposits before delivery, check that a turnkey offer includes every procedure, and ask for a debt-enforcement register extract to check the firm's solvency.
If the work touches older materials, ask who checks for asbestos, PCBs or lead: these substances are still found in Geneva buildings, and such work must follow the rules.
Also check what is included: removal of the old installation and oil tank, commissioning, making good and VAT.
6. Commercial register
What an entry in the commercial register (Zefix) says about a firm, and what it does not, is explained in our Switzerland guide.
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Found an error in this guide?
If a fact in this guide looks wrong or out of date, report it with the form on the Report an error page, giving the sentence concerned and, if you can, an official source.
We review every report within 10 business days. Every substantive correction is dated in the change log below.
Change log
4 November 2026: first published.
Sources
- République et canton de Genève: https://www.ge.ch/installer-remplacer-chauffage (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/installer-remplacer-chauffage/chaudieres-fossiles-mazout-gaz (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/installer-remplacer-chauffage/reseaux-thermiques-structurants-rts (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/installer-remplacer-chauffage/pompe-chaleur (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/energie-aides-financieres/subvention-energie-batiments (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/connaitre-consommation-energie-batiment-idc/proprietaires-immeubles (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/connaitre-consommation-energie-batiment-idc/proprietaires-villas-petits-immeubles-habitation (checked on 2 November 2026)
- République et canton de Genève: https://www.ge.ch/renover-transformer-demolir-sans-danger-amiante-pcb-plomb (checked on 2 November 2026)