For eight weeks, a camera team followed the construction of this summer cottage in Brandenburg. The clou: It is a solar mill, because the arms of this mill are packed with modules. On the four wings, there are 24 solar modules generating 4,4 kW -which corresponds with four-person family energy consumption.

The output of the pv-system can be read from a display in the ground floor. Further, one can read the change in output when the 360-degree-rotatable first floor with its solar wings is turned towards the sun.

Modern technology on an old rooftop. For the lottery of "Building and Renovating", a do-it-yourself magazine, SunEnergy constructed a distinctive sun - symbolizing the production of energy through the sun.