Solar Panel Requirements: What Homeowners Need to Know

Since January 2023, an increasing number of German states have required solar systems on new buildings. If you own property or are planning a build, you may have some important questions. Which rules apply to you? Which technology should you choose? And how can you plan a cost-effective system?

This article explains the legal requirements, outlines ways to comply and helps you take the first steps in planning your project.

What exactly do solar panel requirements mean?

There is no single nationwide solar panel requirement in Germany. Each state has its own rules in its building regulations. The general principle is that when you build a new property, you must install a system that generates solar energy.

The rules mainly affect residential buildings and often apply to new commercial buildings too. In some states, including Baden-Württemberg, they also apply to major roof renovations. Installing a system helps you meet the legal requirements while investing in greater energy independence.

These German states already require solar panels

Baden-Württemberg and Hamburg were the first. Berlin, Bremen, Lower Saxony, Rhineland-Palatinate, Schleswig-Holstein and Saarland followed with their own rules. Other states have passed legislation or are planning to introduce requirements.

The details vary considerably. In Berlin, photovoltaic panels must cover 30 percent of the roof area. In Schleswig-Holstein, a smaller system is often enough. Check the relevant state building regulations to find out exactly what applies to you.

What is the best way to meet solar panel requirements?

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

Most property owners choose photovoltaics. The financial benefit is straightforward: using your own solar power means buying less electricity from the grid. You can also receive payment for feeding surplus power into the grid. A modern PV system often pays for itself within 10 to 15 years.

Choose between PV and solar thermal technology based on your household's needs. If you use a lot of hot water, for example because you have a large family, solar thermal technology can be very efficient. For most households, photovoltaics are the more flexible option.

Planning step 1: Assess your roof

Some roofs are better suited to solar panels than others. A solar installer will check the roof's structural condition, pitch and orientation. A south-facing roof with a 30-degree pitch is ideal, but east- and west-facing roofs can also produce good results.

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

Planning step 2: Choose the system size

Start with the statutory minimum size, then consider sizing the system to match your electricity use. A family of 4 uses around 3500 to 5000 kilowatt-hours per year.

In Germany, a 5-kWp photovoltaic system generates 4500 to 5500 kWh per year, depending on its location. That can cover a large share of your electricity needs. Adding a battery storage system can increase your self-consumption rate to 70 percent or more.

How much does a solar system cost to meet the requirements?

The cost includes the panels, inverter, mounting system and installation. At present, the panels alone cost around 300 to 400 euros per kWp. A typical roof-mounted system, including installation, costs between 1200 and 1800 euros net per kWp.

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

Explore funding and financing options

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

Keep the tax implications in mind: as the operator of a PV system, you are considered a business owner. You can depreciate the system on a straight-line basis over 20 years, which can noticeably reduce your tax bill. A tax adviser can guide you through the first steps.

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

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

Yes. If your roof is unsuitable, some German states allow what are known as alternative measures. These may include buying tenant electricity from a nearby system or joining a community energy project.

You could also lease or rent a system. An investor installs it on your roof, and you buy the electricity at a fixed price. This avoids the upfront investment, but may offer fewer financial benefits over 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.

Optimize 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.