Legal opinion: Germany's new heating law likely unconstitutional
A legal opinion commissioned by the CDU-affiliated Klimaunion concludes that the German government's new building modernization law (Heizungsgesetz) is likely unconstitutional. The draft, presented by Economy Minister Katherina Reiche (CDU) and Construction Minister Verena Hubertz (SPD) and approved by the cabinet, would allow fossil-fuel heating systems to operate indefinitely beyond the 2045 climate-neutrality target. The opinion argues this violates the Federal Constitutional Court's requirement for a coherent emissions-reduction pathway.
A legal opinion commissioned by the CDU-affiliated Klimaunion concludes that the German government's new building modernization law (Heizungsgesetz) is likely unconstitutional, arguing it violates the Federal Constitutional Court's requirement for a coherent emissions-reduction pathway.
The Klimaunion, a group of CDU members advocating pragmatic climate policy, commissioned the opinion, which is circulating in government circles. The draft law was presented by Economy Minister Katherina Reiche (CDU) and Construction Minister Verena Hubertz (SPD) and approved by the cabinet.
The law would abolish the existing requirement for 65% renewable energy when installing a new heating system and remove existing operating bans on fossil-fuel boilers. Instead, it introduces a "Bio-Treppe" (bio-staircase) requiring gradual blending of biogas or hydrogen into fossil fuels for new heating systems.
The opinion states the law permits unlimited continued operation of existing fossil-fuel heating systems beyond 2045, the year Germany has committed to climate neutrality. This, the opinion argues, violates the Federal Constitutional Court's climate ruling, which demands a "coherent overall reduction pathway" that "normatively ensures achieving the target, not just programmatically names it," according to the opinion.
The opinion says the law lacks a binding end date for fossil-fuel heating operation, undermining planning security for investments in heat pumps or district heating. It also argues the law lowers the existing level of climate protection without adequate justification. The government's justification that previous rules were "too complex and impractical" is deemed constitutionally insufficient, as the opinion states complexity and lack of practicality can only justify repeal if a simpler but equally effective regulation is created — which the "Bio-Treppe" does not provide.
The opinion further states the "Grüngas-/Grünheizöl-Quote" (green gas/green heating oil quota) is unrealistic, with a starting volume of "up to one percent" from 2028. To reach 100% within 17 years would require an annual increase of approximately 5.8 percentage points, a trajectory not specified in the law. To make the law constitutional, the opinion recommends setting an end date for fossil-fuel heating operation of December 31, 2044.