The enactment of the Building Modernization Act (GModG) brings about several changes for building owners. With the introduction of the GModG, the following provisions are no longer included in the GEG:

• Elimination of the 65% requirement for newly installed heating systems in new or existing buildings
• Elimination of the requirement to seek consultation when installing new gas or oil heating systems
• Elimination of the requirement to comply with municipal heating plans
• Elimination of the requirement to replace standard and constant-temperature boilers after 30 years

Instead:

• Technology neutrality / Free choice of heating system
• Introduction of the green gas quota (starting in 2028) and a “bio-step” program for gas and oil heating systems
• No operating bans or replacement requirements for specific heating systems

→ Both the GEG and the GModG aim to ensure that heating systems are operated exclusively with climate-neutral fuels starting in 2045 .

With the introduction of the “Bio-Staircase,” fossil natural gas will be gradually replaced in the future by climate-friendly fuels such as biomethane, hydrogen, or synthetic natural gas.

Once the law takes effect on July 29, 2026, the following minimum proportions of climate-friendly fuels will apply to oil and gas heating systems newly installed on or after that date:

• Starting in 2029: at least 10%
• Starting in 2030: at least 15%
• Starting in 2035: at least 30%
• Starting in 2040: at least 60%

This will eliminate the 65% requirement for newly installed heating systems that had previously been in effect under the Building Energy Act.

Subsidies for buildings and heating systems under the federal subsidy program for energy-efficient buildings will continue to be available.

Upon the Building Modernization Act taking effect, a phased implementation of a mandatory solar PV requirement for certain residential and non-residential buildings will begin in accordance with Section 106 of the GModG.

Residential Buildings:

As soon as the law takes effect, new residential buildings must be “solar-ready.” Starting January 1, 2030, the PV requirement will apply to new residential buildings, as well as to covered parking spaces adjacent to a building (e.g., carports).

The Building Modernization Act does not require existing buildings to install PV systems.

Non-residential buildings:

For non-residential buildings, the PV requirement will be phased in gradually, depending on the size of the building’s usable floor area. New (public) non-residential buildings with a usable floor area of more than 250 m² must be equipped with a solar power system as of January 1, 2027.

For existing public non-residential buildings, the requirement to install a solar system will be phased in gradually through 2031. The following phases are planned:

• January 1, 2028: Existing public buildings with a usable floor area of > 2,000 m² or commercial buildings with a usable floor area of > 500 m²
• January 1, 2029: Existing public buildings with a usable floor area of > 750 m²
• January 1, 2031: Existing public buildings with a usable floor area of > 250 m²

Exceptions apply in certain cases, for example, if the installation is technically impossible, functionally unfeasible, economically unreasonable, or conflicts with other public law regulations.