Germany’s 2026 heating law repeal: what GModG requires of buyers

What changed on 29 July 2026

Germany repealed the much‑debated “Heizungsgesetz” rules inside the Building Energy Act (GEG) and replaced the statute with the Buildings Modernisation Act (Gebäudemodernisierungsgesetz, GModG). The new title and regime took effect on 29 July 2026, after publication in the Federal Law Gazette on 28 July 2026. The federal government summarises that the GModG replaces the GEG and removes the uniform 65% renewable‑share requirement for new or replacement heaters. The consolidated text on Gesetze‑im‑Internet shows the new long title and the amendment reference “Art. 2 of 23 July 2026, in force 29 July 2026.”

If you buy and do not replace the boiler

There is no general obligation anymore to scrap an old gas or oil boiler just because it is older than 30 years. In the new codified text, former §§ 71 to 73 (which contained the 65% rule and older boiler replacement duties) are marked “repealed.”

One duty remains relevant for many buyers: insulating the top‑floor ceiling. Owners of heated buildings must ensure uninsulated top‑floor ceilings meet U ≤ 0.24 W/(m²·K), or that the roof above meets minimum standards. For one‑ or two‑family houses that the owner themselves occupied on 1 February 2002, this duty only arises when ownership changes after that date; the buyer then has two years from the first post‑2002 transfer to complete the work. Economic unreasonableness exceptions for owner‑occupied 1–2 family homes remain defined in the statute.

If you replace a heater after completion: the “Bio‑ladder”

Since 29 July 2026 you are free to choose the heating technology. If you newly install a gas, heating‑oil or LPG boiler in an existing building on or after that date, you must operate it with minimum shares of climate‑friendly fuels (“Bio‑ladder”) from the specified dates: at least 10% from 1 January 2029, 15% from 1 January 2030, 30% from 1 January 2035, and 60% from 1 January 2040. The law recognises ways to comply without green gas purchases alone, for example defined solar‑thermal areas through 2034, certain ventilation heat‑recovery performance, or hybrid systems with a heat pump. For small owner‑occupied buildings these technical options are spelled out in § 43.

Documentation is an owner/operator responsibility. Suppliers must confirm the bio‑content on invoices; owners must retain confirmations for the first 15 years of operation and present them to the competent authority on request. Where the operator is different from the owner (e.g., a heat‑supply contract), the operator must meet the share, but the owner should build proof‑keeping into the contract. Special transitional relief applies for emergency replacements due to irreparable failure in calendar year 2028 and for failures from 2029: the bio‑share duty is deferred for twelve months from installation in the circumstances detailed in § 43(7).

Direct‑electric room heating may be installed in existing residential buildings only if the building envelope is at least 30% better than the statutory envelope requirements; exceptions cover small owner‑occupied 1–2 family houses and single‑room replacements. Biomass heaters are allowed if configured as hydronic systems and fired only with fuels listed in the 1st BImSchV; hybrid biomass systems can count toward the bio‑share under § 45.

Multi‑unit assets: checks and hydraulic balancing

For buildings with at least six apartments or other self‑contained units, two operator duties matter for buyers:

- Heat pumps installed after 31 December 2023 must undergo an operational check after one full heating season, and no later than two years after commissioning (§ 60a). - Central hydronic heating systems must undergo a heating check and optimisation: if installed after 30 September 2009, within one year after the 15th anniversary; if installed before 1 October 2009, by 30 September 2027 (§ 60b). The check covers set‑points and efficiency measures; the result and any optimisation must be documented within a year.

Whenever you install a new central heating system in a building with six or more units, a hydraulic balancing of the distribution system is mandatory (§ 60c). District master‑chimneysweeps (bevollmächtigte Bezirksschornsteinfeger) verify compliance in the regular fire‑safety inspection and inform the authority if legal duties are not met (§ 97).

Open items and policy risks you should price in

A separate statute must set the green‑gas/green‑heating‑oil quota for fuel suppliers; the GModG orders the federal government to present this law by 1 December 2026 (§ 42a). The federal Q&A notes the quota will start from 2028, but details are not yet fixed. This is a material risk if you are planning to run a new fossil boiler through the 2030s, because fuel availability and pricing for green blends are uncertain. The federal heating‑upgrade subsidy (BEG) was also retuned from 21 July 2026 with new income‑based bonuses and lower maximums; check KfW/BMWK guidance before you budget.

Commentators differ on what will change next. Some legal analysis highlights forthcoming minimum standards or a “worst‑first” approach for non‑residential stock under the EU Buildings Directive, while the current consolidated GModG shows the dedicated sections for special renovation requirements on existing non‑residential buildings as “repealed.” The Bavarian building ministry, however, points to staged EPBD transposition steps from 1 January 2027, 1 January 2028 and 1 January 2030. Treat these as likely policy headwinds and get written advice specific to your asset.

Who to ask (and what this article is not)

Do not rely on headlines. Before exchange, have a German energy consultant (Energieberater) or HVAC contractor confirm, in writing and with section references, whether your asset has a top‑floor insulation duty, when any heating checks fall due, and what documentation you must keep for bio‑fuel shares. For multi‑unit assets, ask the district master‑chimneysweep about local enforcement practice. For subsidy and rent‑pass‑through questions, speak to a tax adviser and a German real‑estate lawyer. This guide is general information, not legal, tax or investment advice.