Building Modernisation Act (GModG): what companies with non-residential buildings should know

On 28 July 2026, the act amending the Buildings Energy Act, the Building Electromobility Infrastructure Act and other provisions in the heating sector was promulgated in the Federal Law Gazette (BGBl. 2026 I No. 226). The Buildings Energy Act will in future be called the Building Modernisation Act (GModG). The main part enters into force on the day after promulgation, i.e. on 29 July 2026. Further parts follow on 1 January 2027, 1 January 2028 and 1 January 2030. The act transposes the EU Energy Performance of Buildings Directive (EU) 2024/1275. This results in specific obligations and deadlines for companies with office, administrative, warehouse or production buildings.

From the GEG to the GModG

The Federal Cabinet adopted the draft on 13 May 2026, and the Bundestag and Bundesrat passed it in July 2026. The best-known change concerns heating replacement: the previous requirement that new heating systems must be operated with at least 65 per cent renewable energy is abolished. Instead, Section 42 GModG lists permitted options when replacing a heating system in existing buildings, including gas, oil and LPG heating, heat pumps, solar thermal, biomass, hydrogen, hybrid heating, high-efficiency CHP plants, direct electric heating and connection to a heating network.

Anyone installing a gas, oil or LPG heating system in an existing building after 29 July 2026 must ensure, under Section 43 GModG, that a growing share of the heat comes from biomethane, bio-oil, biogenic LPG or hydrogen including derivatives: at least 10 per cent from 2029, 15 per cent from 2030, 30 per cent from 2035 and 60 per cent from 2040. Until the end of 2034, the obligation can also be met via a solar thermal system or a ventilation system with heat recovery that achieves certain values. A green gas and green heating oil quota for distributors is to be regulated in a separate law under Section 42a, which the German government is to present by 1 December 2026.

Building automation by the end of 2029

Section 56 GModG is particularly relevant for non-residential buildings. A non-residential building whose heating, air-conditioning or combined ventilation system has a rated output of more than 70 kilowatts must be equipped with a building automation and control system by 31 December 2029, where technically possible and economically reasonable. The threshold was previously 290 kilowatts. Among other things, the system must continuously monitor, log and analyse the consumption of all main energy sources and technical building systems, provide the data via a common, freely configurable interface, detect efficiency losses, inform the operator about improvement options and monitor indoor environmental quality.

By the same date, automatic lighting control with appropriate zoning and occupancy detection must also be provided in these buildings. For new non-residential buildings, minimum automation levels according to DIN/TS 18599-11 apply, as well as technical commissioning management over at least one heating and one cooling period. For systems installed in the three years before 1 January 2027 that do not meet the requirements, the act contains a transitional rule with a longer deadline.

Minimum requirements for existing non-residential buildings

With effect from 1 January 2027, Section 40 GModG introduces renovation requirements for existing non-residential buildings. From 1 January 2030, annual primary energy demand may not exceed 3.5 times that of a comparable reference building, and from 1 January 2033 no more than 2.95 times. The requirement is deemed to be met, among other things, for buildings constructed from 1996, older buildings with a proven level of thermal insulation under the 1994 Thermal Insulation Ordinance, buildings mainly heated by heat pump or biomass, and buildings supplied with district heating. Exemptions include industrial installations and workshops with low energy demand, listed buildings and buildings whose demolition or abandonment has been decided. The competent authority may request evidence, for example via the energy performance certificate.

Solar obligation, inspections and energy performance certificate

New rules on solar energy under Section 106 GModG also apply from 2027. A solar energy system must be installed on new non-residential buildings with more than 250 square metres of usable floor area from 1 January 2027. For existing non-residential buildings with more than 500 square metres, the obligation applies from 1 January 2028 if certain changes are made to the building and calculations are carried out for the entire building. Exemptions apply in cases of technical impossibility or economic unreasonableness. The federal states may impose further requirements.

From 2027, energy inspection will be extended to ventilation systems with more than 70 kilowatts. Systems above 70 kilowatts must be inspected for the first time in the fifth year after commissioning and every five years thereafter, air-conditioning systems between 12 and 70 kilowatts every ten years. A building automation system under Section 56 can exempt from the inspection obligation. Energy performance certificates are to be issued digitally in machine-readable form in future. An energy demand certificate is required when selling or renting out a non-residential building.

What companies should do now

• For each non-residential building, record the rated output of heating, air-conditioning and ventilation systems and check whether the 70-kilowatt threshold is exceeded.
• Compare existing building management technology with the requirements of Section 56 and plan retrofitting by the end of 2029.
• For older existing buildings, determine whether the minimum requirements from 2030 and 2033 apply or whether an exemption applies.
• For planned heating renewals, include the options under Section 42 and the bio shares under Section 43 in the cost-effectiveness calculation.
• Update inspection deadlines for air-conditioning and ventilation systems.
• Link building measures with the energy audit or energy management system so that data and measures are not collected twice.

How LUNEXS supports you

LUNEXS combines the requirements of the GModG with your company's Energy and sustainability management. Measurement data from building automation can be used for the energy review according to ISO 50001 and for energy audits, and measures for buildings and production are assessed according to uniform criteria. For an initial assessment of your buildings, please get in touch via the contact page .

Technical information. No legal or tax advice and no guarantee or commitment. For a binding assessment of your individual case, please consult a specialist lawyer or tax adviser.