kladnica bulgaria passive energy house

One of the goals of eco-friendly construction is to create homes that not only use fewer resources than conventional homes, but to create those that actually produce more energy than they consume. The house, located in Kladnica, Bulgaria, was designed and built by Studio Apxe. The focus when designing the home was to make it as energy efficient as possible while minimizing its impact on the picturesque mountainous surroundings.

front exterior passive energy house

passive energy house

The home was built on a solid concrete foundation with concrete supporting supporting frames and garage roof, but the rest of the structure is lightweight steel and timber. Thanks to excellent insulation and sun protection, the home needs no cooling in the summer and uses very little heat in the winter. Solar panels on the roof and a biomass heating system contribute to the energy saving and production of the home.

negative energy consumption house

interior passive house apxe studio

A controlled mechanical ventilation system with heat recovery provides the home with fresh air in all seasons. Careful measures were taken to ensure the air-tightness of the home. This feature controls energy loss and qualifies the house as passive by keeping the energy consumption around 38 kWh per square meter annually, a figure that falls far below the 120 kWh per square meter requirement.


Construction of the home used as many locally-sourced materials as possible. Other energy saving methods, such as separating the garage and other colder spaces from the living spaces, are employed to further increase the single-story home’s eco-friendly rating.