Flammersfeld in the Westerwald. Surrounded by farmland stands Jürgen Heermann's greenhouse, which covers more than 300 square meters. The special thing about it: In the greenhouse, in turn, there is another 150-square-meter house made of clay. This is the actual home of the 72-year-old. More than 15 years ago, he bought his dream of a house with that "certain something".

In principle, he says, the superstructure is nothing more than a greenhouse. However, he says, it was built exclusively and from the outset to protect the adobe house around it. Above all, the climatic conditions common in a greenhouse also make living in the house in the glass house an energy-efficient house with very low energy costs, far below the average.

Thus, in winter - despite cool temperatures outside - inside there is a pleasantly mild climate. On sunny winter days, it can even get quite warm, and this is then transferred to the actual living area in the adobe house.

For more than 30 years, Jürgen Heermann flew around the world as an on-board engineer in the cockpits of jumbo jets. Whether New York, Rio or Tokyo - with retirement he was looking for a house that was not off the peg. Jürgen Heermann remembers it well: Shortly before Christmas 2006, he found the offer on the Internet that impressed him so much and immediately drove to the high Westerwald for an inspection. Only a short time later, the purchase contract was sealed.

The seller, a practicing shaman, had the house built naturally and ecologically, without artificial building materials, such as construction foam or other plastics. Today one would probably call it sustainable. At that time still rather a rarity. Only from loam, straw and wood it is built. The house would not be able to withstand the weather, wind and rain, the glass house serves as a shelter.

The advantage: inside the greenhouse creates its own atmosphere, its own climate. This allows even a pomegranate tree, next to an olive tree and three other trees in the high Westerwald through all seasons to grow and bloom. However, Jürgen Heermann has to water the trees by hand or much more with a hose. He does this conscientiously once a month. The green lungs of the glass house swallow 750 liters of water. He takes the water for this - quite sustainably - from his rainwater cistern. He also has to trim the trees once a year, otherwise they would outgrow his glass house.

Jürgen's actual home, the adobe house, also offers some refinements. The living room, for example, is a semicircular room that forms the center of the building. On the ceiling, beams run radially outward from a center point like tent poles. The resulting open spaces are supplemented with skylights that bathe the room in daylight. From the dining table, Jürgen can thus gaze at the open sky. In addition to the living room, bedroom and kitchen, the residence has two bathrooms, a guest room and a study. All with skylights and an unobstructed view of the sky.

6,000 panes of glass protect the adobe house from wind and weather. The glass surfaces on the roof are made of safety glass, similar to a car. Normal window glass is installed on the sides of the greenhouse.

Jürgen Heermann says that many visitors to his house believe that it must be oppressively hot in his glasshouse in midsummer. Quite the opposite, he says. On hot summer days, the glass house can be ventilated through automatic window openings on the sides and in the gable of the roof. They thus ensure a pleasant climate. And if the sun does shine too strongly, a thermal screen - a white tarpaulin - can be automatically raised between the gable of the roof and the house. This reflects the sun's rays and keeps the heat in the house at night. Jürgen Heermann leaves window cleaning entirely to the rain, which is quite enough, he says.

A film by Jörg Hommer (editor), Lars Reuther (camera), Paul Heydecke (sound), Susanne Dejung (drone) and Frank Rosam (editing).

00:00 House in glass house
01:14 Living area in glass house
02:36 Roof
06:37 Living room
07:14 Kitchen
07:59 Hallway
08:10 Bedroom
08:32 Study