Solar Panel Requirement: What Homeowners Need to Know

Since January 2023, more and more German states have required solar systems on new buildings. As a homeowner or property developer, you face some important questions. Which law applies to you? Which technology do you need to choose? And how can you plan your system cost-effectively?

This article guides you through the legal requirements. We explain the obligation, outline ways to comply and help you make the initial plans for your project.

What exactly does the solar panel requirement mean?

The solar panel requirement is not a uniform nationwide regulation. Each German state has its own rules set out in its state building regulations. The common principle is this: when building a new property, you must install a solar energy generation system.

This mainly affects residential buildings and often commercial new builds as well. In some states, such as Baden-Württemberg, the requirement also applies to major roof renovations. So you are not building only to comply with the law—you are also investing in your own energy independence.

These German states already have a solar panel requirement

The pioneers were Baden-Württemberg and Hamburg. Berlin, Bremen, Lower Saxony, Rhineland-Palatinate, Schleswig-Holstein and Saarland followed with their own rules. Other states have passed legislation or are currently planning it.

The details vary considerably. In Berlin, photovoltaic panels must cover 30 percent of the roof area. In Schleswig-Holstein, a smaller system is often sufficient. Checking the relevant state building regulations will give you certainty.

What is the best way to meet the solar panel requirement?

You have two main options: photovoltaics (PV) or solar thermal technology. Photovoltaic panels generate electricity for your own use and for feeding into the grid. Solar thermal collectors heat your domestic hot water and support your heating system.

Most property developers choose photovoltaics. The reason is financial: using your own solar power reduces expensive electricity purchased from the grid. You can feed surplus power into the grid in return for payment. A modern PV system often pays for itself within 10 to 15 years.

The choice between PV and solar thermal technology should always be based on an individual needs assessment. Anyone who uses a lot of hot water, for example because of a large family, can use solar thermal technology very efficiently. For most people, photovoltaics are the more flexible solution.

Planning step 1: Analyse your roof

Not every roof is equally suitable. A solar installer will check the structural stability, roof pitch and orientation. A south-facing roof with a 30-degree pitch is ideal. However, east- and west-facing roofs can also produce good yields.

Shade from trees, chimneys or neighbouring buildings reduces output. A professional yield forecast will clarify the situation. For planning, you can also find practical tools and measuring devices in our Garden + Outdoor section.

Planning step 2: Determine the system size

The statutory minimum size is your starting point. However, it makes financial sense to match the system to your electricity consumption. A family of 4 uses around 3500 to 5000 kilowatt-hours per year.

A 5-kWp photovoltaic system generates 4500 to 5500 kWh per year in Germany, depending on its location. This can cover a large proportion of your needs. If you include a battery storage system, you can increase your self-consumption rate to 70 percent or more.

How much does a solar system cost for compliance?

The investment consists of the panels, inverter, mounting system and installation. At present, the panel costs alone are around 300 to 400 euros per kWp. The total cost of a typical roof-mounted system, including installation, is between 1200 and 1800 euros net per kWp.

For a 10-kWp system, this means an investment of 12,000 to 18,000 euros net. These costs are before VAT. As a private individual, you can reclaim the full VAT through income from feeding electricity into the grid.

Make use of funding and financing

KfW supports photovoltaic systems and battery storage through the “Renewable Energies – Standard” programme. You receive a low-interest loan. Some German states and municipalities offer their own grant programmes.

Do not forget the tax implications: as the operator of a PV system, you are a business owner. You can depreciate the system on a straight-line basis over 20 years. This can noticeably reduce your tax burden. A tax adviser can help you with the initial steps.

Many property developers underestimate the tax benefits. Depreciating the investment costs over several years can significantly ease the pressure on the household budget. Seek expert advice early on to make the most of all available benefits.

Are there alternatives to installing a system on your own roof?

Yes, if your roof is unsuitable. In some German states, the authorities also accept what are known as alternative measures. These include purchasing tenant electricity from a nearby system or joining a community energy project.

Another option is a lease or rental model. An investor installs the system on your roof and you purchase the electricity at a fixed price. This avoids the upfront investment, but offers fewer financial benefits in the long term.

What happens after installation?

Your installer registers the system with the grid operator and the Federal Network Agency. You will receive approval to feed electricity into the grid and a metering point. The grid operator will often replace your electricity meter with a modern digital two-way meter.

The operating phase now begins. Have the system serviced regularly. Check its output using a monitoring system. Clean the panels if they become heavily soiled. You can find suitable cleaning accessories in the garden tools range.

Optimise self-consumption

Financial success depends on self-consumption. Run energy-intensive appliances such as washing machines and dishwashers when the sun is shining. A modern heat pump or an EV wallbox can use solar power directly.

Also think about supplying your garden and home. Solar-powered garden irrigation or lighting does not reduce the load on the system, but it does make use of free energy. Practical electric vehicles are also ideal for outdoor use and can be charged with your own solar power, such as the

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The solar panel requirement as an opportunity for your home

The legal requirement is initially an obligation. However, it can be the starting point for a modern, cost-saving energy supply. You are investing in stable electricity costs over the long term and increasing the value of your property.

Sustainable construction is becoming the standard. A solar system is a visible sign of this. It significantly reduces your CO2 footprint. Plan your project carefully and make use of the advice available. The first step is to speak to a qualified solar installer.

We are here to support you with a wide range of products for all your other home and garden projects. Browse our main Shop category or explore specialist areas such as Tarpaulins + Nets to find what you need.

Frequently asked questions

Which homes does the solar panel requirement apply to?

The requirement primarily applies to newly approved residential buildings. In states such as Baden-Württemberg and Hamburg, it also applies to new commercial buildings and, in some cases, larger roof renovations. Existing buildings without renovation work are generally not required to comply. The details are set out in the state building regulations.

How large does the solar system have to be?

The minimum size varies by state. There is often a requirement covering a percentage of the roof area (e.g. 30% in Berlin) or a minimum output in kilowatt-peak (kWp). For a typical single-family home, this often means a system between 5 and 10 kWp. Check with your local authority.

Can I use solar thermal instead of photovoltaics?

Yes, in most states you can meet the requirement with either a photovoltaic system for generating electricity or a solar thermal system for hot water and heating support. Combinations are sometimes possible. The choice depends on your energy needs and the available subsidies.

How much does a solar system cost for the requirement?

For a complete rooftop photovoltaic system including installation and inverter, you should expect to pay 10,000 to 20,000 euros net. The exact cost depends on the size, component quality and condition of the roof. Government subsidies and tax depreciation reduce the net investment.

Are there any exemptions from the solar panel requirement?

Yes, exemptions may apply in cases such as insufficient sunlight, listed buildings or undue financial hardship. Technical obstacles such as structural problems may also qualify for an exemption. An application must be submitted to the responsible building control authority.