Germany’s Residential Rooftops Hold €45.43 Billion in Value as GreenSketch Releases First Nationwide Rooftop Valuation Report

Munich, Germany, June 23, 2026 — On the eve of Intersolar Europe, GreenSketch, the AI-powered solar digitalization platform under OSW Group, officially announced its entry into the German market and released the German Rooftop Valuation Report. It is Germany’s first AI-based study to individually analyze and assess the value of more than 28 million detached residential rooftops nationwide.

According to the report, Germany’s residential rooftops hold up to €45.43 billion in potential annual energy value and electricity bill savings. However, only around 4.1 million households have installed solar systems so far, leaving a large share of rooftop resources still untapped.

The report was launched during the GreenSketch Germany Launch event held at Villa Flora in Munich, bringing together guests from manufacturers, energy institutions, media, and industry organizations. During the event, GreenSketch presented its core AI technology, Emily, and hosted discussions on Germany’s residential energy transition, rooftop asset value, and future trends in energy storage.

As a next-generation solar digitalization platform developed by OSW Group, GreenSketch is designed to help installers and homeowners develop solar projects more efficiently. The platform integrates rooftop analysis, system design, intelligent quotation, and customer acquisition into one workflow, significantly shortening the traditional solar sales process through AI technology.

Traditionally, installers often need to use multiple software tools to complete design and quotation work, with the process from customer inquiry to formal quotation usually taking several days. GreenSketch’s AI assistant Emily can complete the full process — from rooftop analysis and system design to quotation generation — within minutes.

For homeowners, by simply entering an address, they can understand the solar value and savings potential of their rooftop within one minute and connect directly with local installers.

According to the German Rooftop Valuation Report, without considering any government subsidies, a typical German household installing a 10.34 kWp PV system and a 9.6 kWh energy storage system can save approximately €1,620 in electricity costs per year on average. The average payback period is 8.44 years, with cumulative 20-year returns reaching €19,030 and an internal rate of return of 11.5%. If this model is applied to all 28 million residential rooftops in Germany, the total 20-year economic benefit is expected to reach €533.7 billion.

The report also highlights clear regional differences across Germany. Bavaria ranks first nationwide across key indicators, with an average 20-year return of €20,504 per household. Berlin, by contrast, ranks relatively lower, with an average 20-year return of €14,555. The study found that southern Germany, particularly the Allgäu and Upper Bavaria regions, has more favorable rooftop conditions, with Kempten identified as the region with the highest investment return nationwide. Nevertheless, even lower-ranking regions still show significant economic benefits from solar projects, demonstrating the strong potential for distributed PV development across Germany.

GreenSketch believes the timing of the report is significant. According to data from the German Solar Association (BSW Solar), residential PV installations in Germany declined by 21% year-on-year in the first quarter of 2026.

At the same time, Germany still needs to accelerate progress toward its 215 GW solar installation target by 2030. As Germany’s draft EEG 2027 proposes gradual adjustments to subsidy mechanisms for small-scale PV systems, the importance of energy storage systems continues to rise. In this new market environment, homeowners and installers will have an increasing need for accurate data analysis and project return assessments.

Christian Seidemann, Head of GreenSketch DACH, said: “As Germany’s energy market rules continue to evolve, homeowners and installers need more accurate data to understand the true value of rooftops. This report is the first to provide address-level rooftop valuation across Germany, and it proves that even without subsidies, solar and storage systems still deliver long-term economic value.”

Unlike traditional studies that rely on statistical modeling, the German Rooftop Valuation Report is based on GreenSketch’s self-developed AI system, Emily, which individually analyzes all 28 million residential rooftops across Germany.

By combining satellite imagery, AI-powered 3D building reconstruction, and GIS geographic information system technology, the platform can identify each building’s orientation, roof pitch, and shading conditions. It also achieves more than 87% accuracy in 3D building reconstruction, enabling truly address-specific valuation results.

The German Rooftop Valuation Report was jointly released by GreenSketch, LONGi, and GoodWe, with support from industry partners including Anker SOLIX, Antai, Astronergy, Fox ESS, and Hoymiles.

GreenSketch stated that Germany is an important starting point for its European market strategy. Going forward, the platform will gradually expand into more European countries, using artificial intelligence to help more installers improve customer acquisition efficiency and accelerate the residential energy transition across Europe.