Gebäudeenergiegesetz (GEG) 2023 – German Building Energy Act
The Gebäudeenergiegesetz (GEG), or Building Energy Act, is a German federal statute issued by the Bundesministerium der Justiz (Federal Ministry of Justice) in collaboration with the Bundesamt für Justiz. Originally enacted on August 8, 2020, the document has been most recently amended by the law of October 16, 2023 (BGBl. 2023 I Nr. 280). It serves as the primary legal framework for energy efficiency and the use of renewable energy for heating and cooling in the German building sector, transposing several European Union directives including Directive 2010/31/EU on the energy performance of buildings.
The act governs regulatory domains concerning energy savings and the integration of renewable energies in both new constructions and existing building stock. It defines technical requirements for heating, cooling, ventilation, and lighting systems, as well as the provision of domestic hot water. Structured into nine parts and eleven annexes, the document includes specific sections on Niedrigstenergiegebäude (nearly zero-energy buildings), Jahres-Primärenergiebedarf (annual primary energy demand), and Energieausweise (energy performance certificates). It also establishes concrete thresholds for building components, thermal insulation, and the mandatory use of renewable energy sources in heating systems.
The following sections detail the core regulatory requirements, technical procedures, and transitional arrangements for property owners and industry professionals as defined in the GEG 2023.
Scope and Statutory Definitions
According to §2 Anwendungsbereich, the GEG applies to all buildings that are heated or cooled using energy, along with their internal technical systems. However, §2(2) lists several exemptions where the act does not apply, except for specific inspection requirements:
- Agricultural buildings: Structures used primarily for rearing or keeping animals.
- Small buildings: Any building with a total floor area of 50 square meters or less.
- Temporary structures: Tents, air-supported halls, and buildings intended for a duration of use of up to two years.
- Religious buildings: Dedicated places of worship or those used for other religious purposes.
- Residential buildings with limited use: Buildings used for less than four months annually or those where energy consumption is less than 25 percent of expected year-round use.
Requirements for New Constructions
Per §10, new buildings must be constructed as nearly zero-energy buildings (Niedrigstenergiegebäude). Compliance is measured through two primary metrics defined in §15 for residential and §18 for non-residential buildings:
- Primary Energy Demand: The annual primary energy demand for heating, cooling, ventilation, and hot water must not exceed 0.55 times the value of a defined Referenzgebäude (reference building).
- Structural Thermal Insulation: For residential buildings, the specific transmission heat loss must not exceed 1.0 times the value of the reference building.
- Minimum Insulation: Components must meet specific standards defined in DIN 4108-2 to ensure minimum thermal protection.
Heating System Requirements and Renewable Energy
A central pillar of the 2023 amendment is §71, which mandates that newly installed heating systems must generate at least 65 percent of the heat demand from renewable energies or unavoidable waste heat (Abwärme). Compliance options include:
- Heat Pumps: Electrically driven systems as per §71c.
- District Heating: Connection to a heating network as per §71b.
- Biomass and Hydrogen: Systems utilizing solid biomass, biomethane, or hydrogen derivatives as per §71f and §71g.
- Solar Thermal: Integration of solar thermal systems to supplement heat demand.
Furthermore, §72 prohibits the operation of oil or gas boilers installed before January 1, 1991, and sets a final deadline of December 31, 2044, after which no fossil-fuel boilers may be operated.
Energy Performance Certificates (Energieausweise)
§79 to §88 regulate the issuance and mandatory disclosure of energy certificates. These documents are generally valid for ten years and must be presented during the sale or leasing of property.
- Issuance: Certificates can be based on calculated demand (Energiebedarfsausweis) or measured consumption (Energieverbrauchsausweis).
- Display Obligations: Owners of buildings with more than 250 square meters of floor area visited by the public must display the certificate in a clearly visible location.
- Real Estate Ads: Mandatory information in commercial advertisements includes the type of certificate, the energy demand/consumption value, primary energy source, and efficiency class (A+ to H).
Frequently Asked Questions
What is the 65 percent renewable energy rule for heating?
According to §71, any heating system newly installed or set up for operation must generate at least 65 percent of the heat demand from renewable energy sources or unavoidable waste heat.
When must old oil and gas boilers be decommissioned?
Boilers installed before January 1, 1991, generally cannot be operated. Under §72, the final date for any fossil-fuel-based heating operation in Germany is December 31, 2044.
What is the maximum U-value allowed for external wall renovations?
Annex 7 (Anlage 7) specifies that for external wall modifications in residential buildings, the heat transfer coefficient (U-value) must not exceed 0.24 W/(m²·K).
Are energy certificates mandatory for all building sales?
Yes, §80(4) requires that an energy certificate or a copy be presented to potential buyers at the latest during the property viewing.
Which buildings are exempt from the GEG requirements?
Exemptions include small buildings under 50 sqm, temporary structures used for up to two years, underground structures, and buildings dedicated to religious services as per §2.
What happens if a property owner violates the GEG?
Administrative offenses, such as failing to insulate ceilings or incorrectly installing heating systems, can result in fines up to 50,000 euros according to §108.
