German Bundestag opens debate on new heating law, with coalition pledging overhaul of predecessor's 65-percent rule

Under the reform, the existing law would be renamed the Building Modernization Act. The coalition's central move is to remove the so-called 65-percent rule, which has applied since 2024 to newly installed heating systems in new development areas and requires that 65 percent of the energy used come from renewable sources. In its place, the draft keeps a wider menu of options open: heat pumps, district heating connections, hybrid heating models, biomass heating, and, from 1 January 2029, new gas and oil heating systems provided they use a rising share of CO2-neutral fuels such as biomethane.

What changes under the new draft

Reiche argued that the heat pump will nevertheless be the leading technology in the vast majority of buildings, telling the chamber: 'Die Wärmepumpe werde in den allermeisten Gebäuden die Leittechnologie sein, weil sie eine wirtschaftlich vernünftige Lösung sei.' She said the federal government is replacing heating mandates with technological openness and is 'giving people back the freedom' to choose their systems. She added: 'Die Bürgerinnen und Bürger entscheiden über den Weg zur klimaneutralen Wärmeversorgung. Wir als Staat geben die Leitplanken vor,' and framed the bill as 'einen Schlussstrich unter eine Politik des Misstrauens.'

Two new supply-side instruments are planned: a 'Grüngasquote,' a green-gas quota that suppliers must meet for existing heating systems from 2028 onward, and a 'Biotreppe' — a bio-staircase — meant to ease the transition to climate-friendly heating. Existing buildings, however, retain extensive transition periods, and functioning heating systems may continue to be operated under the existing rules.

A cost brake for tenants

The coalition has also agreed on a cost brake for tenants. When landlords install a new gas or oil heating system, the cost risks from grid fees, the CO2 price, and biogas are to be split equally between tenants and landlords. Federal Building Minister Verena Hubertz (SPD) said the government wants and must make heat supply climate-neutral by 2045: 'Wir wollen und wir müssen die Wärmeversorgung bis 2045 klimaneutral gestalten.' She called the old heating law a 'Bauplan' that did not work in practice and said: 'Wir haben diesen Plan jetzt neu gezeichnet. Klar, tragfähig und mit den richtigen Stützen an den richtigen Stellen.'

Opposition: cost trap and climate setback

Opposition speakers sharply criticized the draft. Greens parliamentary group leader Katharina Dröge warned that the reform represents a cost trap and a setback for climate protection. She noted that the cost-sharing rule does not apply to commercial premises, telling the chamber: 'Das bedeutet, dass hunderttausende kleine Betriebe wie Friseursalons, Bäckereien, Handwerker und Pflegedienste von hohen Mehrkosten alleine betroffen sind.'

Violetta Bock, Die Linke's climate policy spokesperson, said her faction will use all legal and parliamentary means to stop the law. She argued that the bill 'fails three times' — on climate protection, on social justice, and on constitutional conformity — and invoked Article 20a of the Basic Law, which she said contains a 'Verschlechterungsverbot,' a prohibition on regression in existing climate protection measures. Die Linke is examining whether to halt the new regulations with an Organklage, an institutional complaint, in expedited proceedings before the Federal Constitutional Court.

Constitutional challenge ahead

AfD member of parliament Marc Bernhard attacked the bill in even stronger terms, calling Reiche's modernization law 'Habeck's heating hammer through the back door' and arguing that the bio-staircase amounts to a de facto ban on oil and gas heating. The reform is widely seen as a break with legislation passed by the former 'Ampel' coalition and significantly shaped by Reiche's predecessor, Robert Habeck of the Greens.

Environmental associations and parts of the energy industry have also raised concerns, warning that the reform could become a cost trap if green gases remain too expensive in the foreseeable future. The debate on Thursday was a first reading; the bill is now set to move through committee and further parliamentary stages, with the constitutional challenge and the unresolved question of green-gas costs likely to dominate the next phase of the fight over Germany's heat transition.