Germany's heating law 2026: what really applies to your heating now

Your heating is running, and for years you have been reading that it has to go. For owners of a residential building this was turned on its head in summer 2026: since 29 July 2026 there has been neither a replacement duty for existing heating systems nor the requirement that a new system runs on 65 per cent renewable energy.

This article goes through heating law as it stands in the Act today — and only that: the existing heating system, the new gas boiler, the breakdown, heat planning, funding and the point at which the heating appears in the energy performance certificate.

#What is meant by the “heating law” — and what has applied since 29 July 2026?

“Heating law” (Heizungsgesetz) is not an official name but the colloquial term for the heating provisions of the Building Energy Act (Gebäudeenergiegesetz, GEG). Since the amendment of 23 July 2026 it has been called the Building Modernisation Act (Gebäudemodernisierungsgesetz), GModG for short; promulgated on 28 July 2026, with the heating rules in force from the following day. The energy performance certificate rules of the same amendment only take effect in 2027 — both dates are explained in the Building Modernisation Act: what has applied since July 2026.

The decisive sentence of the amendment is short: §§ 71 to 73 are deleted.3 § 71 contained the 65 per cent requirement, § 72 the operating ban for old boilers, § 73 the transitional periods. They have not been suspended but removed; the federal GEG information portal also counts the duty to seek advice among the rules that have been dropped.

They are replaced by a different design: free choice of appliance, conditions on the fuel. § 42 (2) GModG names ten permissible options for replacing a heating system — from gas, heating oil and liquefied petroleum gas through heat pump, solar thermal, biomass and hydrogen to a building connection station for a heating network.1 None of them is prohibited, but none comes without conditions either.

#Do I have to replace a working existing heating system?

No. No provision of the Building Modernisation Act prohibits the operation of an existing heating system after a certain number of years. In the current version, the word “Heizkessel” (boiler) appears only in the definitions of § 3 and in a rule for new buildings — in no prohibition.

Two duties remain: the maintenance duty under § 60 GModG — and one with a deadline. A heating system with water as the heat transfer medium that was installed before 1 October 2009 and runs in a building with at least six flats must be inspected and optimised by 30 September 2027.4 This does not apply to detached and two-family houses.

Why no renovation duty follows from the building envelope is set out in renovation duty: six claims and what the Act really says.

#What applies if I install a new gas or oil heating system now?

You may install it — and take on a duty that only begins in a few years. Under § 43 (1) GModG, for a gas, heating oil or liquefied petroleum gas heating system newly installed after 29 July 2026, the owner must ensure that a growing share of the heat comes from biomethane, bio-oil, biogenic liquefied petroleum gas or hydrogen.2

These shares can also be met without the fuel: via solar thermal, a ventilation system with heat recovery or a hybrid heating system with a large heat pump or biomass share. This is not a recommendation: anyone who misses the quota commits an administrative offence with a fine of up to 5,000 euros.

#What happens if the heating breaks down beyond repair in the middle of winter?

Less than many fear. Because there is no requirement for the replacement, there is also no deadline by which you have to catch up on anything. Anyone who has a gas boiler installed in January 2027 after a total breakdown does so without conditions; the bio shares begin on 1 January 2029.

A special rule concerns only the start of the quota: if a fossil system is installed in 2028 because of an irreparable breakdown, the duty only applies twelve months later; from 2029, the level that applied at the time of the breakdown continues to apply for twelve months (§ 43 (7) GModG). One detail of the funding helps: the rental costs of a temporary heating system are eligible, for no more than one year from the date of application.

#What role does municipal heat planning still play?

For your decision: a big one. For your duties: none. The interlinking that the old law had has been dissolved — the word “Wärmeplan” (heat plan) does not appear even once in the entire Building Modernisation Act, and the amendment removed the references in the Heat Planning Act (Wärmeplanungsgesetz) to the deleted sections.8

The Heat Planning Act says so in § 27 (1): designating an area as a heating network or hydrogen network expansion area “does not create any obligation actually to use a particular type of heat supply”.7 No compulsory connection follows from it.

The heat plans are coming all the same: municipalities with more than 100,000 inhabitants had to deliver by 30 June 2026, all others by 30 June 2028. Whether district heating is planned in your street or the gas network is being dismantled is stated there — as information, not as an order.

#What does the state pay in 2026 when you replace your heating?

The applicable scheme is KfW grant 458, in the version in force since 21 July 2026: 30 per cent basic funding, plus for owner-occupiers a climate speed bonus of 16 per cent and an income-related bonus of 40, 30 or 10 per cent. Capped at 70 per cent, or 80 for low incomes — calculated on no more than 28,000 euros for the first residential unit.10

The most important point, however, is in the list of eligible technology: heat pump, solar thermal, biomass, fuel cell, hydrogen-ready heating, connection to a heating or building network — but not a new gas or oil heating system. Permitted and funded are two different lists. And the bonus is shrinking: for the first time on 1 February 2027, then by four percentage points every six months.

Then there are the running costs: for a detached house of 130 square metres, co2online calculates around 24,500 euros up to 2045 for an air-to-water heat pump against around 55,600 euros for a gas boiler. Everything beyond heating is covered in energy-efficient renovation and funding 2026.

#What does heating law have to do with the energy performance certificate?

More than the separation of the topics would suggest. Among its mandatory details, the certificate lists the year of construction of the heat generator and the main energy sources for heating and hot water (§ 85 (1) GModG). A heating replacement changes it in two places — and, via the performance indicator, usually the efficiency class too.

This becomes visible when you sell or re-let: § 87 (1) GModG requires every property advertisement to state the main energy sources for heating named in the certificate. Anyone who advertises a heating system that no longer exists risks a fine of up to 10,000 euros. At Energieausweis Portal a demand certificate (Bedarfsausweis) costs 119.90 €, a consumption certificate (Verbrauchsausweis) 69.90 € — the difference is explained in what an energy performance certificate costs, and you can order via the demand certificate form.

#Conclusion: no duty today, a decision with a long tail

Heating law 2026 asks nothing of you as long as your heating is running — the talk of forced modernisation disappeared with §§ 71 to 73. It only sets the course when you replace anyway: then the choice of appliance decides whether from 2029 you carry a fuel quota backed by fines and whether there is a grant. That decision is better made calmly than on the weekend the boiler fails.