Heating Law Reform: Bundestag Passes "Bio-Staircase" Instead of 65-Percent Rule

At the center of the previous regulation was the so-called 65-percent rule. It stipulated that every newly installed heating system should be operated with 65 percent renewable energies. This requirement, which since taking effect in 2024 initially applied to new buildings in new development areas, was criticized as complicated and overly detailed. With the new law, Section 71 with the „Anforderungen an eine Heizungsanlage" is to be dropped without replacement.

Core of the Reform: Abolition of the 65-Percent Rule

Economics Minister Katherina Reiche (CDU) made clear in the Bundestag that the federal government wanted to replace „Heizungszwänge" with technological openness. With a view to the existing regulations, she had spoken of a „Zwang zur Wärmepumpe". The draft formulates the goal as follows: „Der Eigentümer hat wieder Entscheidungsfreiheit, welche Heizungsoption er wählen möchte." The CDU/CSU had also demanded in its election program: „Mit dem bürokratischen Reinregieren in den Heizungskeller muss Schluss sein."

In concrete terms, the reform means: In addition to heat pumps, district heating connections, hybrid heating models, or biomass heating systems, new gas and oil heating systems should continue to be installable. The prerequisite is that from 1 January 2029 onwards, they use an increasing proportion of CO₂-neutral fuels such as biomethane. A „Bio-Treppe" is planned, which provides for gradually higher quotas.

The "Bio-Staircase" in Detail

BUND climate expert Tina Löffelsend explained the stages in detail: From January 2029, at least 10 percent climate-friendly fuels are to be used; from January 2030, at least 15 percent; from January 2035, at least 30 percent; and from January 2040, at least 60 percent. For the year 2045, a share of 100 percent is ultimately planned, which the federal government intends to regulate in a separate law by early December: „2045 müssen es dann schon 100 Prozent sein."

Parallel to the bio-staircase, a „Grüngasquote" (green gas quota) for existing heating systems is to be introduced from 2028. Until the goal of climate-neutral fuels is achieved, CO₂ levies on the fossil share of heating fuels will also continue to rise. However, a provision that heating boilers may no longer be operated with fossil fuels from 2045 has been dropped from the new draft.

Cost Distribution Between Tenants and Landlords

The reform also provides for a distribution of the expectedly rising costs between landlords and tenants. The background is that tenants must bear the heating costs, regardless of how expensive the chosen form of heating becomes in the long term. So that tenants and landlords are not equally penalized for sticking with a gas heating system, some landlords are being given the chance to shift most of the costs back onto tenants – however, they must fulfill a whole series of conditions to do so.

The lobby association Haus & Grund sharply criticized this planned cost distribution. Shortly before the end, a hardship provision was therefore added to the law, which under certain conditions permits a deviating cost distribution in favor of landlords. Observers see this as a response to the ongoing criticism from the landlords' lobby.

The Committee on Economic Affairs and Energy has already passed the amendment to the Building Modernization Act. This clears the way for parliamentary deliberation in the Bundestag and Bundesrat. The amendment is regarded as a political core project of the black-red coalition and ties in with the years-long dispute over the predecessor regulation, which had been driven forward above all by Robert Habeck (Greens) as the then Economics Minister.

Criticism from Environmental Associations and Constitutional Concerns

The reform is highly controversial. Environmental associations such as the Deutsche Umwelthilfe have already described the planned new law as constitutionally „höchst zweifelhaft". They refer to a landmark ruling by the Federal Constitutional Court from 2021, which essentially stated: Drastic steps to reduce CO₂ emissions must not be postponed at the expense of the younger generation. Critics fear an impending „Klimalücke" (climate gap), because the new provisions make the targets for reducing climate-damaging CO₂ emissions more difficult to achieve.

Tina Löffelsend from BUND formulated the criticism as follows: „Die Hitzewellen dieses Sommers sind ein weiterer Weckruf für mehr Klimaschutz." Yet the federal government is significantly stoking the climate crisis further with the Building Modernization Act. Critics also complain that the federal government wants to pass a law without knowing the costs and availability of „grüner" gases.

Many associations warn of a „Kostenfalle" (cost trap) with new gas heating systems. In the long term, higher costs threaten due to rising CO₂ prices and gas network charges. The heat sector has long been considered a „Sorgenkind" (problem child) in climate protection, because a large share of German heating systems continues to run on fossil fuels and the expansion of renewable heat is only making sluggish progress.

Outlook on the Parliamentary Deliberations

Germany has set itself the goal of being climate-neutral from 2045 onwards. Whether the reform is compatible with this goal will be shown by the further political and legal dispute. What is clear is that the amendment will have far-reaching consequences not only for climate policy, but also for tenancy law and consumer policy.

The news about the planned law was broadcast on 10.07.2026 on the Deutschlandfunk program. Final passage by the Bundestag and Bundesrat is considered likely, as the governing factions have the necessary majorities there. However, observers expect lawsuits and an intense public debate in the coming weeks.