The move from the technology giant and energy firm marks the first time the solar viability calculator has been available outside the US.
Google’s technology, which allows householders to easily determine their home’s potential solar capacity, will cover around seven million buildings in Germany, including those in major urban areas like Munich, Berlin, Rhine-Main and the Ruhr.
The website calculates how much sunlight falls on a roof during the course of a year, taking into account the weather, the position of the sun, shadows from other objects and the area and slope of the roof.
It then works out how much solar energy could be generated and calculates potential cost savings.
E.ON has guaranteed the service, promising to provide financial compensation for any shortfall in output.
Karsten Wildberger, Chief Operating Officer of E.ON, said: “With Project Sunroof, we are able to digitise sales of solar systems more intensively and thereby increase the appeal of photovoltaics.
“It clearly demonstrates the potential benefits of digitalisation for the ongoing shift in energy production.”