Solar Requirement in Germany: What Homeowners Need to Know

The new rules for photovoltaic systems on your roof.

What exactly is the solar requirement?

The solar requirement is a legal rule. It requires property owners to install a solar system when constructing a new building or carrying out major renovations. Its aim is to expand the use of renewable energy in the building sector. The law is intended to bring the energy transition directly to rooftops.

The requirement does not apply only to private homes. Commercial new builds and, in many cases, large car parks are also covered. The specific rules are set by the federal states. There is therefore no single nationwide German solar requirement law.

For you as a homeowner, this means you must follow the laws of your federal state. The requirement is a building standard, and compliance is checked by the responsible building control authority.

The solar requirement is a key lever for accelerating the expansion of solar power and achieving climate targets in the building sector. It gives the industry greater planning certainty and firmly establishes solar energy as part of everyday construction.

Which German states have solar requirements?

The rules are a patchwork. Some states already have requirements in force, while others are still planning or discussing them. This overview provides guidance.

Baden-Württemberg was the first German state to introduce a solar requirement for new buildings in 2022. Since 2023, it has also applied to major roof renovations. In Berlin, since 2023, all new buildings and buildings undergoing roof renovations have had to install solar systems. Bavaria has a photovoltaic requirement for commercial new builds and large car parks.

Hamburg, North Rhine-Westphalia and Schleswig-Holstein have adopted similar rules for new buildings. In Rhineland-Palatinate, the requirement applies to new commercial buildings and car parks. Details such as the minimum system size vary considerably.

How do I find the rules for my federal state?

The state building codes or separate renewable energy laws contain the relevant requirements. Search for your federal state's “state photovoltaic law” or “state solar law”. The websites of state governments and solar industry associations provide up-to-date summaries.

Your architect, energy consultant or the responsible building office caseworker will know the exact requirements. Obtain this information early in the planning process to avoid delays and additional requirements.

Who exactly is subject to the requirement?

The requirement targets two main groups: people building new properties and owners of existing buildings who are substantially renovating their roofs. The definition of “substantial” is crucial.

For new buildings, the rule is clear. You apply for planning permission for a residential or commercial building. Approval is granted only if your application demonstrates that a solar system will be installed. In most states with solar requirements, this applies regardless of the building's size.

Existing buildings are more complicated. The requirement often only applies when you renovate more than 10% or 25% of the roof area. Replacing a few individual tiles usually does not trigger the requirement. Completely re-roofing your property, however, does. Check the rules before starting your roof renovation.

Many homeowners underestimate the trigger effect of a roof renovation. As soon as the roof covering is opened up on a larger scale, the solar requirement applies in many states. Integrating the system into the planning is then easier and more cost-effective than installing it later.

Are there exemptions from the solar requirement?

Yes, the laws provide for hardship exemptions. Typical reasons include permanent shading of the roof by trees or neighbouring buildings. Listed buildings can often also be exempt.

Another reason is technical impossibility. If your roof's structural capacity cannot support a solar system, this may justify an exemption. Financial hardship is subject to a strict standard. You must prove that the system's payback period would be disproportionately long.

The burden of proof lies with you as the applicant. You will often need an assessment from a recognised expert. The building control authority then decides on your exemption application.

What type of system is required?

As a rule, the laws require the use of renewable energy. A photovoltaic system for generating electricity is the standard option. It fulfils the requirement in almost all cases.

Some state laws also allow solar thermal systems for heating water. However, these are less often the first choice. Combining photovoltaics with a heat pump is often more efficient. You must check the exact requirements in your state's regulations.

How large does the photovoltaic system need to be?

The minimum size depends on the federal state. It is often defined as a percentage of the roof area or as a minimum output in kilowatt peak (kWp). Typical requirements include “20% of the roof area” or “at least 3 kWp”.

For a typical detached house roof, 20% of the roof area often corresponds to a system of 6 to 10 kWp. This usually exceeds the absolute minimum requirements. Use your own electricity bill as a guide. Size the system to cover a large share of your annual consumption.

A mandatory system that is too small may barely pay for itself. Take the opportunity to install a high-performance system straight away. The additional costs are relatively low, while the extra yield over 20 years can be substantial.

What does implementation cost?

The investment for a typical mandatory solar installation on a detached house is between 8.000 and 15.000 euros excluding VAT. The range is considerable. It depends on the required capacity, the condition of the roof and the installation method.

A simple pitched roof with good access costs less. A complex apartment-block roof with many penetrations drives up costs. As a rough guide, allow for 1.200 to 1.600 euros per kWp of installed capacity, including installation.

The good news is that you do not have to bear these costs alone. The government supports photovoltaic systems through the KfW with low-interest loans. Many federal states and even local authorities offer additional grant programmes. Under certain circumstances, you may also be able to reclaim VAT on the installation and battery storage system.

What ongoing costs and returns can I expect?

Ongoing costs are low. They consist of servicing every few years and insuring the system. Your returns come from the electricity you save by using your own power and from the feed-in tariff.

The more solar power you use yourself, the greater your savings. The current electricity price is over 30 cents per kilowatt-hour. Every kWh you use yourself saves you this amount. The feed-in tariff is currently around 8 cents per kWh. This provides additional income for electricity that you do not use yourself.

A well-sized system with battery storage can cover 60% to 80% of your electricity needs. The payback period is often 8 to 12 years today. The system can then continue operating for another 15 years or more, with virtually no further costs for you.

How do I plan my system?

Start early. Integrate photovoltaic planning into the overall planning of your building or renovation project. The first step is an initial yield forecast for your roof.

Use the solar potential maps available online from many local authorities. They show the potential of your roof area. Then commission a specialist contractor to carry out detailed planning. This includes a structural assessment, selecting the components and precise system sizing.

Do not forget to register the system. Your electrical installer will register it with the grid operator and the Market Data Register. These formalities are mandatory. Your specialist contractor should support you with them.

What mistakes should I avoid?

The biggest mistake is planning too late. If the solar system is treated as an annoying obligation at the end, it will lead to poor solutions. Plan it from the outset as an integral part of your energy system.

Avoid cheap panels from unknown manufacturers. The quality of the panels, and especially the inverter, determines the system's service life and yield. Look for long product warranties and high-quality workmanship.

Do not overlook the possibilities of solar-powered garden irrigation. A garden pump or automatic irrigation system can be perfectly combined with your new installation.

Think about the future, too. When installing the electrical system, plan empty conduits from the loft to the basement for possible future upgrades. An electric vehicle charger or a more powerful inverter can then be added easily later on.

The role of specialist contractors and energy advisers

A certified photovoltaic specialist contractor is your most important partner. They know the local regulations, the best components and the typical installation pitfalls. Obtain quotes from contractors with the appropriate certification, e.g. from the “Elektrotechnik Handwerk” or the “Handwerkskammer”.

An independent energy adviser can provide impartial planning advice. They can calculate different options for you and help with applications for grants. The cost of this advice is often a very worthwhile investment.

For practical work and maintaining your outdoor area, you will find everything you need in the garden tools and power tools sections. You can also make the more sociable side of energy independence enjoyable, for example with a

Gas Pizza Oven COMO (Germany/Austria version), 50mbar

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FARO 3B gas barbecue (Germany/Austria version), 50mbar

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For a natural atmosphere in the garden, perhaps even for your own smoker,

15 kg Goldspan B 7/20 smoking chips, 1,0-2,5 mm

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The solar requirement is more than an obligation. It is an opportunity to make your home future-proof and more economical. With a well-planned photovoltaic system, you become less dependent on rising energy prices and invest in the value of your property. Start planning today.

Frequently Asked Questions

Who is subject to Germany’s solar requirement?

The solar requirement primarily applies to new residential and commercial buildings, as well as major roof renovations on existing buildings. The exact regulations vary from one federal state to another. In some states, car parks and commercial buildings must also have a solar installation. Always check the specific regulations in your federal state.

Is a solar thermal system sufficient, or does it have to be photovoltaic?

That depends on the federal state. Most solar requirement laws require the use of renewable energy to generate electricity, meaning photovoltaics. In some cases, solar thermal energy for hot water production or heating support may also be recognised. However, a photovoltaic system is the most common and flexible solution for meeting the requirement.

What happens if I ignore the solar requirement?

Failure to comply with the statutory solar requirement may result in your new-build project being denied a building permit. If you carry out a renovation without installing the required system, the completed work may not be signed off. Fines are generally possible. Compliance is monitored by the building control authority and is a prerequisite for using the building.

Are there any exemptions from the solar requirement?

Yes, exemptions are generally provided for in the legislation. Typical reasons include insufficient sunlight, heritage protection, technical impossibility or unreasonable financial hardship. The latter often has to be demonstrated by an expert report. As the property developer, you are responsible for providing the evidence and applying for approval of an exemption.

How much does a mandatory solar installation cost?

The cost of a typical mandatory installation for a single-family home starts at around 8.000 to 12.000 Euro net. The exact amount depends on the required capacity, the roof size and the complexity of the installation. Government funding, such as low-interest KfW loans or regional grants, can significantly reduce the investment.