Germany’s Building Energy Act in 2026: what applies under the new name
The Building Energy Act still exists, only under a new title. Here is the version in force for the energy certificate, the efficiency class and the duties when you buy, sell or let.
Worked through by Radif Partners · Editorial policy · How we calculate
Your efficiency class
Class
E
| Final energy a year | 18,850 kWh |
| Air heat pump electricity | 4,801 kWh |
Reference climate, not adjusted for your state.
Germany’s 2020 Building Energy Act (Gebäudeenergiegesetz, GEG) has been called the Building Modernisation Act (GModG) since 29 July 2026. The main deletions are the heating rules in sections 71 to 73, namely the 65 % duty and the replacement duty after 30 years. The rest still applies: requirements for new builds and renovations, insulation duties after a change of ownership, inspection duties for heating in larger buildings and the energy performance certificate (Energieausweis). Anyone selling a house or letting a flat must show a valid certificate, which lasts ten years and gives the efficiency class under annex 10, from A+ to H. A 140 m² house with a final energy figure of 145 kWh per m² is in class E and needs about 20,300 kWh a year; an air source heat pump there would use about 5,171 kWh of electricity. From 1 January 2027 certificates are issued digitally, and the class limits for homes stay the same.
One law, two names
Many contracts, quotes and official letters still refer to the GEG. That is not wrong: article 1 of the act of 23 July 2026 only replaced the title and changed or deleted individual sections. The abbreviation on gesetze-im-internet.de stayed the same, and so did the numbering. The main deletions are sections 71 to 73 with the 2024 heating rules; new are sections 42, 42a and 43 with free choice and the staged duty for new gas and oil boilers (heating law). There is no official English translation of the current text, so rely on the German one.
Efficiency classes under annex 10
Under section 86 the class in the certificate follows directly from final energy consumption or demand per square metre of floor area per year. The limits are in annex 10.
| Class | kWh per m² a year | House of 140 m² |
|---|---|---|
| A+ | up to 30 | up to 4,200 kWh |
| A | over 30 to 50 | up to 7,000 kWh |
| B | over 50 to 75 | up to 10,500 kWh |
| C | over 75 to 100 | up to 14,000 kWh |
| D | over 100 to 130 | up to 18,200 kWh |
| E | over 130 to 160 | up to 22,400 kWh |
| F | over 160 to 200 | up to 28,000 kWh |
| G | over 200 to 250 | up to 35,000 kWh |
| H | over 250 | over 35,000 kWh |
The class describes the amount of energy, not the type of heating. A class E house at 145 kWh per m² burns about 20,300 kWh of gas with a boiler. Because a heat pump turns one kWh of electricity into several kWh of heat, it would need about 5,171 kWh of electricity in the same house, based on a boiler efficiency of 87 % and the measured seasonal performance factor of 3.4. The calculator below does this conversion with your figures, without adjusting for your state’s climate. The full calculation by location is under heat pump electricity use.
Energy certificate: when, which, how long
| Occasion | Duty | Section |
|---|---|---|
| New build | demand-based certificate on completion | 80(1) |
| Major renovation with whole-building calculation | new demand-based certificate | 80(2) |
| Sale, letting, leasing | show a valid certificate at the viewing at the latest, hand it over after signing | 80(3) and (4) |
| Property advert | five mandatory details if a certificate exists | 87 |
| Buying a house with up to two homes | consultation for the buyer, where offered free | 80(4) |
A certificate is valid for ten years (section 79(3)). If you live in your house and neither sell nor let, you do not need one. From 1 January 2027, under article 2 of the amending act, it is issued digitally in a machine-readable format, on paper on request. The reference area changes at the same time: annex 10 will then refer to heated or cooled floor area under a new standard. The class limits A+ to H stay the same for homes, while non-residential buildings get their own scale in annex 10a. When buying, ask for the certificate early: as a foreign buyer you may not otherwise see the class before the notary appointment.
Keep the oil boiler or switch
Grant if you switch now
€12,880
| CO₂ a year at €65/t | €455 |
| Oil a year (12-month average) | €2,611 |
Running it is allowed: the 30-year replacement duty ended on 29 July 2026.
Duties that come with the house
If you buy a one or two-family house, you have two years to insulate the top floor ceiling if it falls short of minimum thermal protection (section 35), and accessible, uninsulated heating and hot water pipes in unheated rooms (section 69). When windows, roof or facade are renewed, the new parts must meet the limits in annex 7, as long as more than 10 per cent of the relevant area is affected (section 36). Buildings with six or more homes add the check and optimisation of older heating under section 60b and hydraulic balancing under section 60c. For smaller houses BAFA funds optimisation on a voluntary basis (heating optimisation). What applies to an old oil boiler when you buy is under oil heating ban.
What no longer applies from the 2024 version
Guides written before August 2026 often list duties that no longer exist: the 65 % rule for new heating, deadlines tied to municipal heat planning, mandatory advice before fitting fossil heating and the operating ban on boilers after 30 years. They were in the 2024 version and applied until 28 July 2026. The heating cost calculator works out the running costs of your house.