Legislation and entry into force
The Bundestag passed the GModG on 10 July 2026; the Bundesrat did not call on the mediation committee. The act was promulgated in the Federal Law Gazette on 28 July 2026 (BGBl. 2026 I No. 226), and its core provisions entered into force on 29 July 2026. Further parts follow in stages in 2027, 2028 and 2030.
In substance, it is not an abolition but a reform: the GEG continues under a new name and with amended obligations. Further legal challenges to the act are expected; details may still change through follow-up legislation.
What applies to heating systems
The obligation to use at least 65% renewable energy when installing a new heating system (§ 71 GEG old version) has been abolished. Oil and gas heating systems may continue to be operated and may also be newly installed.
Instead, a so-called bio-fuel staircase (Bio-Treppe) applies to newly installed gas, oil or liquefied gas heating systems: a minimum share of climate-friendly fuels (biomethane, bio-oil, hydrogen) of 10% from 2029, 15% from 2030, 30% from 2035 and 60% from 2040. It can also be met through hybrid systems with a heat pump or solar thermal energy. From 2045, heating fuels must be completely climate-neutral.
The previous obligation to replace boilers more than 30 years old (§ 72 GEG old version) has been abolished without replacement. For operators of existing gas and oil heating systems, a quota for green gas or green heating oil is planned from 2028, the details of which are to be regulated by a further act by the end of 2026.
Costs for landlords
For newly installed gas or oil heating systems, network charges, CO₂ costs and the additional costs of bio-fuels are, under the amended rules of the CO₂ Cost Allocation Act (CO₂-Kostenaufteilungsgesetz), in principle to be split equally between landlord and tenant. For existing heating systems, the CO₂ costs continue to be split according to the tiered model based on the building's energy consumption.
According to specialist reports, anyone installing a heat pump that does not meet the statutory efficiency requirements risks being able to pass modernisation costs on to tenants only to a limited extent. Have modernisations assessed legally and technically beforehand.
Energy performance certificate on sale
Sellers or agents must present an energy performance certificate (Energieausweis) or a copy to prospective buyers at the latest at the viewing; this can also be done by displaying it clearly. If no viewing takes place, it must be presented without delay, at the latest on request. After the purchase contract has been concluded, it must be handed over to the buyer without delay (§ 80(4) GModG).
In commercial property advertisements – if an energy performance certificate exists – the type of certificate, the energy demand or consumption value, the main energy source, the year of construction and the efficiency class must be stated (§ 87 GModG). An energy performance certificate is valid for ten years.
What this means for older flats
For buyers of existing flats, the GModG removes the immediate pressure to replace a working oil or gas heating system. In the long term, however, the costs of fossil fuels will rise as a result of the CO₂ price, the bio-fuel staircase and the green gas quota.
Check before buying: the age and type of the central heating, resolutions of the owners' association on heating, insulation or windows, the size of the maintenance reserve and the efficiency class in the energy performance certificate. With individual heating systems in the flat (e.g. a gas heater serving a single flat, Gasetagenheizung), decisions often concern only the individual owner.
Reading an energy performance certificate
There are two types: the demand certificate (Bedarfsausweis) calculates the energy demand from the construction and the building services, while the consumption certificate (Verbrauchsausweis) is based on the occupants' actual consumption in recent years. Consumption values depend heavily on user behaviour and vacancy; demand values are easier to compare between buildings.
Residential buildings are classified into efficiency classes from A+ (very efficient) to H. For older buildings, pay attention to the figure in kWh per m² per year, the energy source and the modernisation recommendations attached to the certificate.
According to the BBSR information portal, the implementation of the EU Energy Performance of Buildings Directive (EPBD) is to take place later in a separate step; the content of the energy performance certificate may therefore still change.
Do I have to replace my old gas heating?
Under the GModG, no; the obligation to replace boilers more than 30 years old has been abolished. For operators of existing systems, a green gas quota is planned from 2028, the details of which are still to be regulated.
Does the 65% rule still apply?
No. It was repealed by the GModG (in force since 29 July 2026).
Do I have to see the energy performance certificate before buying?
The seller must present it at the latest at the viewing and hand it over after the contract has been concluded.
