Municipal heat planning is a strategic planning tool that outlines how Mainz’s heat supply can be made climate-friendly, reliable, and affordable. It identifies climate-friendly supply options in various urban areas—such as district heating networks and decentralized solutions like heat pumps.

Since January 1, 2024, municipal heat planning has been required by law (Heat Planning Act). Large cities such as Mainz must submit a finalized heat plan by June 30, 2026. Coordinated planning prevents costly individual solutions, provides planning certainty for building owners, and enables a socially responsible heating transition.

The municipal heating plan builds on the findings of the Heating Master Plan 2.0, which was developed by Mainz Public Utilities. These findings are expanded upon, refined, and supplemented with input from local stakeholders. Municipal heating planning uses more up-to-date data and adopts a more granular approach to area divisions. As a result, the findings of the Heating Master Plan 2.0 are now outdated.

Effective immediately, municipal heating planning will be used as a valid informal planning tool for future decisions. Detailed information on the Heating Master Plan 2.0 can be found on the Mainz Public Utilities website: 

Upon adoption by the City Council on June 17, 2026, the plan will become binding and will serve as a basis for planning and decision-making by the city administration and energy providers.

For building owners, however, there is no direct legal obligation arising from the heating plan. Binding requirements for owners stem exclusively from the Building Energy Act (GEG), not from the heating plan itself.

The municipal heating plan outlines the climate-friendly heating options available in Mainz. As a resident, you have no direct obligations—the plan provides guidance on topics such as district heating networks, heat pumps, and funding opportunities. For property owners in particular, it can serve as a valuable basis for decision-making regarding future investments.

You can actively stay informed, participate in community events, and share your suggestions or concerns. You can also check whether your own heating system is already efficient or can be converted to renewable energy.

The state capital of Mainz regularly provides updates on the progress of its heating plan through informational events and its website, www.mainz.de/waermeplanung (opens in a new tab). You can also contact them directly by email at waermeplanungstadt.mainzde.

By law, the heating plan must be completed by June 30, 2026. The City Council adopted the resolution on June 17, 2026. Implementation of the measures has already begun and will proceed gradually over many years, extending through 2035 and 2040. So there is no sudden deadline by which everything will be completed. The implementation of Mainz’s Heating Plan is an ongoing process that will continue over the next few years.

No. The Heating Plan does not directly require you to take action. Binding requirements for your heating system are set forth exclusively in the Building Energy Act (GEG): If you replace your heating system on or after June 30, 2026, the new system must use at least 65 percent renewable energy. Existing, functioning heating systems may continue to be operated.

In the Mainz-Lerchenberg area, connection to the district heating network has been mandatory since 1984. Whether a mandatory connection to an expanded or new district heating network will be introduced in the future depends on various factors. If a mandatory connection were deemed appropriate in certain areas, the city council would have to decide on the matter in a separate resolution. Currently, there is no basis for such a decision.

Yes, existing heating systems may generally continue to be used. However, if you need to replace your heating system, the requirements of the Building Energy Act (GEG) will apply starting June 30, 2026: The new system must then use at least 65 percent renewable energy. The GEG—not the Heating Plan—is the applicable legal basis here. You can find information on this, for example, at the Consumer Advice Center:

The Heating Plan is not a personalized guide, but it helps you assess your own situation: First, check which type of heating supply is shown for your area (district heating network or decentralized solution). Keep in mind that the plan provides long-term guidance through 2035 or 20240—specific timelines for the actual expansion of district heating networks will be developed in subsequent phases. If you’re planning to replace your heating system or renovate your home, it’s worth looking into current incentive programs and seeking independent energy counseling, e.g., through the Consumer Advice Center:

Various renewable energy technologies are being used: heat pumps, solar thermal energy, district heating, and geothermal energy. The specific choice depends on local conditions and the availability of resources. Mainz is particularly well-suited for this: In many neighborhoods, the subsoil is very well suited for near-surface geothermal energy. In addition, the Rhine, the wastewater treatment plant (wastewater heat), data centers and businesses (industrial waste heat), as well as solar energy on rooftops, offer great potential. In the future, hydrogen is likely to play a role primarily in industry and mobility, rather than in building heating.

District heating is distributed via a large, citywide pipeline network and often comes from central generation plants. Local heating, on the other hand, supplies smaller, geographically limited areas—such as a neighborhood or a district—via a local network. Both systems can be operated in a climate-friendly manner, for example using geothermal energy, waste heat, or solar thermal energy as heat sources. In Mainz, the largest district heating provider is Mainzer Fernwärme GmbH, with its main generation plants located on the Ingelheimer Aue. In addition, there are district heating service areas on the Lerchenberg and in the Berliner Siedlung, which are supplied by Mainzer Wärme PLUS.

The municipal heating plan identifies various renewable heating sources and outlines how district heating could be provided in a climate-friendly manner. Every heating network operator is required to develop a transition plan detailing how heat will be provided in a climate-neutral manner in the future. The municipal heating plan serves as a guide in this process.

The draft identifies areas in various city districts that are suitable for district heating. Detailed maps can be found at www.mainz.de/waermeplanung (opens in a new tab). If you have questions about your specific area, we recommend contacting the project team directly (by email at waermeplanung@stadt.mainz.de)waermeplanungstadt.mainzdewaermeplanungstadt.mainzde

Green methane and green hydrogen are identified in the Municipal Heat Plan as potential options under certain conditions.

The Heating Plan recommends prioritizing the use of green hydrogen in energy-intensive industrial processes, particularly where high temperatures are required and electrification is not feasible. For the building sector, hydrogen is considered a secondary solution, as heat pumps are generally more efficient and cost-effective.

Because every building is different. The state capital of Mainz does not enact laws or make individual investment decisions on your behalf. The heating plan is intended to provide guidance, but it does not prescribe any specific technology. The right solution for your home depends on many personal factors—be sure to seek personalized advice.

The Heating Plan divides the city of Mainz into four types of areas. Depending on which area your building is located in, different recommendations apply. 

A heat pump is generally a good choice. Subsidies are currently high, which makes switching to a heat pump early on financially attractive. If you’re planning renovation work anyway, it makes sense to consider the future use of a heat pump from the very beginning. You should also contact Mainzer Fernwärme or Mainzer Wärme Plus to find out whether connecting to the district heating network might be an option for you.

Under current law, the installation of a gas heating system is still permitted until June 30, 2026, provided that it gradually switches to biogas starting in 2029. However, we do not recommend this: Gas prices are expected to continue rising—partly due to CO₂ pricing—so the total cost of a gas heating system is likely to be higher over the years than that of a heat pump. If you need to act urgently, please first seek a personalized energy consultation.

That’s not a drawback. For buildings that aren’t connected to a district heating network, there are so-called individual heating solutions—such as heat pumps or solar thermal systems. Subsidies are also available for these solutions. All options share the same goal: affordable and climate-neutral heat for your home.

The housing industry is actively involved in the planning process, and social impact is a top priority. When carrying out renovations, the legal regulations governing renovation cost-sharing and the available subsidy programs must be taken into account. As a tenant, you have no direct obligations under the heating plan.

Yes. The federal government and the states offer various incentive programs to support the transition to renewable energy and energy-efficient heating systems. Be sure to seek personalized advice on how to apply—the landscape of available incentives changes regularly. You can find the latest information at:

This is especially true if your heating system is old or malfunctioning, or if you’re planning renovation work anyway. The current high subsidy rates often make switching early a financially attractive option. Align your decision with the municipal heating plan to choose the right technology for your area.

By providing timely and transparent information, property owners can plan ahead and take advantage of currently available funding. Coordinated infrastructure planning prevents costly ad hoc solutions. And the use of local energy sources—such as waste heat from data centers—ensures more stable prices, independent of fossil fuel imports.

The Building Modernization Act (GModG) is a proposed federal law intended to replace or amend the current Building Energy Act (GEG) in the future. However, it has not yet entered into force and is still going through the legislative process. For you as a resident of Mainz, this does not result in any new obligations at this time. The current GEG remains the sole applicable law.

Political guidelines do not yet constitute a legally binding framework and therefore do not provide a reliable basis for long-term investment decisions. The municipal heating plan outlines which heating options are available in your neighborhood in the medium and long term—regardless of current political debates. The state capital of Mainz recommends neither waiting nor rushing into decisions, but rather seeking individualized advice.

Yes. A stable energy supply is our top priority. The expansion or construction of district heating networks will not affect the heat supply for the residents of Mainz.

The expansion of district heating networks and the expansion of power grids for renewable heat supply require temporary construction sites. However, the long-term benefits for residents—more affordable, climate-friendly heat—will outweigh these temporary inconveniences.

In addition, the number of construction sites will be minimized as much as possible through long-term coordination with various infrastructure projects. It is also planned (where possible) to use the construction work to enhance public spaces.