GModG for Industrial Enterprises: Changes Compared to the GEG in Heating Systems and Building Equipment

The Building Modernization Act (GModG) has been the applicable revision of the Building Energy Act (GEG) since 29 July 2026. The focus is on the gradual energy modernization of the building stock towards climate neutrality and on economically sensible, technology-neutral solutions. Government heating subsidies are also being comprehensively reformed.

A central innovation concerns new gas, heating oil and liquefied petroleum gas heating systems in existing buildings: in future they must meet minimum shares of renewable fuels or hydrogen that increase step by step. Industrial buildings with poor energy performance may be particularly affected.

In addition, the threshold for the obligation to implement building automation is being significantly lowered: affected non-residential buildings with heating, air-conditioning or ventilation systems with a rated output of more than 70 kW must be equipped with the required systems and with automatic lighting control by 31 December 2029, unless an exception applies.

This article highlights the key innovations of the GModG compared to the previous GEG and explains what industrial companies need to consider regarding heating systems and technical building equipment.

What does the GModG mean specifically for industrial companies?

The GModG is particularly relevant for industrial companies that own, rent, newly build or comprehensively modernize operational buildings, production halls, warehouses, administrative buildings or mixed-use properties. If a heating, air-conditioning or ventilation system is replaced or expanded at an industrial site, companies must in addition to technical availability also consider fuels, evidence, building automation, lighting control and investment timelines.

Which innovations of the GModG are particularly relevant for industrial companies?

For industrial companies, the following changes are particularly central:

• The previous blanket 65 percent renewable energy requirement when installing new heating systems is eliminated. In its place, new compliance options and additional requirements apply to the respective heating system chosen. Owners can once again choose between heat pumps, district heating, hybrid heating, biomass, as well as gas or oil heating systems.

• When newly installing gas, heating oil or liquefied petroleum gas heating systems in existing buildings, the minimum shares of renewable fuels increase stepwise from 10 percent as of 2029 to 60 percent as of 2040, with planned climate neutrality from 2045 as the building sector’s contribution to the goal of the Climate Protection Act.

• Fuel options particularly include biomethane, bio oil, biogenic liquefied petroleum gas, as well as green, blue, orange and turquoise hydrogen.

• Alternatively, certain technical combinations, including solar thermal energy, heat recovery or a heat pump hybrid heating system, can meet the requirements.

• For affected non-residential buildings, the relevant output threshold for building automation and monitoring decreases from more than 290 kW to more than 70 kW rated output.

• Additionally, an automatic, appropriately zoned lighting control system with occupancy detection is required.

What requirements apply when newly installing fossil-fuel heating systems?

For industrial companies, it is crucial to distinguish between the operation of an existing system and the new installation of a heating system. The obligation covered by the key innovations concerns the new installation of gas, heating oil or liquefied petroleum gas heating systems in existing buildings. For a specific project, the system, its purpose, the installation date and the building must therefore be clearly delineated. It is important to note that a new fossil-fuel heating system may be permissible in the short term but may be associated with significant fuel, conversion and investment risks in the longer term.

The minimum shares increase according to the following schedule:

The permissible renewable fuel or hydrogen options referenced in the regulatory content include biomethane, bio oil, biogenic liquefied petroleum gas, as well as green, blue, orange or turquoise hydrogen. The respective statutory definition, quality, origin and proof of compliance must be verified for the specific product.

Which alternative compliance options can industrial companies use?

The obligation can also be fulfilled through technical combinations under the prescribed compliance options. For industrial companies, the following variants may be particularly relevant:

• Solar thermal system in combination with the heating system.

• Ventilation system with heat recovery.

• If a heating system is fired with gas, heating oil or liquefied petroleum gas, the following applies to a heat pump hybrid heating system: a heat pump share with regard to output at part-load point A under DIN EN 14825 of at least 30 percent, or in bivalent alternative operation at least 40 percent of the peak load generator output in bivalent parallel or bivalent partial-parallel operation, depending on the specific compliance option.

• Biomass or hydrogen heating, provided the requirements for fuel and system are met.

• Other heating options provided for in the GModG, such as heat pumps, district heating, solar thermal energy, combined heat and power, or direct electric heating, provided the respective prerequisites are met.

In industry, the compliance option should not be assessed solely on the purchase price. Also to be considered are peak load, operating hours, redundancy, process and space heating, fuel availability, supply contracts, metering, evidence, space requirements, grid connection and the interfaces with energy management.

Which fuels are taken into account in the GModG?

For industrial planning, the definition of fuels is particularly important because it influences procurement, supplier evaluation and long-term site strategy. The focus is on:

• Biomethane as a gaseous biogenic fuel.

• Bio oil as a liquid biogenic fuel.

• Biogenic liquefied petroleum gas.

• Green, blue, orange or turquoise hydrogen, insofar as the statutory requirements and evidence are fulfilled.

Companies should not rely solely on product designations or supplier statements. In tenders and supply contracts, quality, origin, sustainability attributes, quantities, evidence, testing and retention obligations as well as liability in the event of non-recognition should be stipulated.

What changes in building automation and monitoring?

The relevant output threshold drops significantly. Under the GModG, affected non-residential buildings with heating, air-conditioning or ventilation systems or combined systems with a rated output of more than 70 kW must, as a rule, be equipped with a system for building automation and building control or the required monitoring technology by 31 December 2029, unless the equipment is technically impossible or economically unreasonable. The GModG sets high requirements here. Technical impossibility exists, for example, if the existing structural and technical conditions truly cannot be implemented; with respect to economic impossibility, it is not sufficient that the required investments do not amortize in the short term. The existence of the prerequisites must in all cases be demonstrable. The previous GEG generally tied the corresponding obligation to a threshold of more than 290 kW rated output.

As a result, medium-sized industrial buildings that previously fell below the 290 kW-rated-output threshold are also covered. For the assessment of whether a building is affected, companies must record at least the rated output, system type, use, year of construction, existing control, measurement points and interfaces for each building and system.

According to the official overview, the monitoring technology is intended, among other things, to monitor, log and analyze consumption, enable vendor-independent data evaluation, create benchmarks, detect efficiency losses, indicate improvements and monitor indoor climate quality.

What is new in automatic lighting control?

Lighting control is explicitly included for the first time in the equipment obligation. Affected non-residential buildings must, as a rule, be equipped with automatic, appropriately zoned lighting control and occupancy detection by 31 December 2029. Technical impossibility or economic unreasonableness may justify an exception according to the underlying regulatory content.

For production and logistics sites, companies should examine whether production areas, storage zones, traffic routes, offices and ancillary rooms can be controlled separately in an appropriate manner. In addition, presence or occupancy detection, switching and dimming functions, safety requirements, operating hours and communication with building automation must be evaluated.

Which requirements apply to new buildings?

In new industrial and non-residential buildings, the requirements must already be taken into account in planning and tendering. According to the official overview, the following points are particularly relevant:

• For systems with a rated output of more than 290 kW, a building automation system with Automation Level B according to DIN/TS 18599-11:2025-10 is envisaged.

• For systems between 70 kW and 290 kW rated output, Automation Level C according to DIN/TS 18599-11:2025-10 is generally envisaged according to the official overview.

• The communication of the connected technical building systems must work across manufacturers and devices.

• The commissioning of the technical building systems is to be carried out as part of technical commissioning management.

The requirements should be reflected in service specifications, requirement specifications, tenders, contracts, acceptance protocols and the technical project documentation. If interfaces are clarified only after installation, retrofits, delays and disputes over responsibility are likely.

What should industrial companies do now?

Implementation should be set up as a site-wide technical and organizational project:

Which evidence should be available for audits and authorities?

For compliance, it is not sufficient to retrofit a system. Companies must also be able to demonstrate that they have reviewed scope, deadlines, compliance options and responsibilities. A site-specific GModG file should in particular include:

• Building list with use, system allocation and rated outputs.

• Inventory of heating, air-conditioning, ventilation and lighting systems.

• Decision and reasoning for the selected heating or hybrid solution.

• Fuel evidence, supplier declarations, metering concepts and consumption data.

• System description of building automation and monitoring, including interfaces.

• Proof of lighting zones, occupancy detection and control functions.

• Planning, tendering, commissioning and acceptance documents.

• Assessment of exceptions, exemptions or economic unreasonableness.

• Responsibility matrix, overview of deadlines and documented controls.
  
  

Conclusion: Integrate the GModG into site and compliance governance

For industrial companies, the GModG is not just a change to heating regulations. It links fuel requirements with building automation, monitoring, lighting control, investment planning and evidence. The Bio staircase influences long-term fuel and procurement strategy. Lowering the threshold to more than 70 kW rated output significantly expands the circle of affected non-residential buildings. Lighting control additionally brings a technical area into the GModG process that previously was not captured in the same way.

The next sensible step is a structured GModG check for your own building portfolio: record systems and rated outputs, evaluate planned new installations, prioritize retrofits by 2029, define roles and evidence, and anchor the results in the legal register as well as in investment, procurement and maintenance processes.

FAQ on the GModG 

Leo Unland

Dipl. Jur.
Legal Compliance Expert
l.unland@eticor.com
+49 151 7288 4059

Tim Bieber

LL.M.
Legal Compliance Expert
t.bieber@eticor.com
+49 6022 2656 127