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Challenge / Goal

Kindergarten „Slantse“ in Gabrovo is the first certified passive building in Bulgaria. The project was initiated by the municipality and the Centre for Energy Efficiency EnEffect, and received technical support from the Municipal Energy Efficiency Network EcoEnergy.


It is a two-storey building. In view of the laid down high requirements for energy efficiency, its form, orientation and internal dispositions of the rooms are complied with the principles of maximum thermal benefits of the solar heat and minimum thermal wastage due to constructive thermo bridges and external glazing.

Children’s space (including a bedroom, a children’s corner for play, a kitchen and a sanitary unit) and a multifunctional hall are situated on the grand level of the building. The hall has a direct exit, combined with a pergola, to an entrance platform in the southern part of the yard. There are isolated offices and store rooms in accordance with the requirements for such type of buildings. In regard to the requirements for an accessible environment, there is a platform for the second level. A corner for children’s play is laid out under the stairway. A doctor’s surgery with isolation space and a sanitary unit are located near the lobby. On the second level of the building there is space for two children’s groups, planned with the same features like the children’s space on the ground floor - bedrooms, children’s corners for play, sanitary units and a kitchen.

All external walls are built from hollow bricks, thick 25 cm, and thermal insulation from the outside – 20 cm EPS. The roof has thermal insulation with glass wool, thick 30 cm, put in the upper part of the concrete slab. The internal walls are built from bricks as well. The floor slab, bounded by the ground, has thermal insulation of 18 cm EPS from the bottom and 2 cm EPS above the slab for shielding of underfloor heating. The window frames are replaced with PVC profiles which have high thermal insulation parameters with the necessary air tightness, secured during the installation thanks to seal tapes.

The rooms are provided with radiant floor heating systems, working at temperatures between 32-37 degrees Celsius. The main heating source is an air/water heat pump aggregate with an electric stand-by heater. When the winter temperatures are very low, a central heating station is turned on as additional and reserve capacity. A combi boiler for heating through solar systems with selective collectors is also provided. 

After successfully implemented air tightness test and based on the presented results, the building is awarded with a „Certified Passive House“ certificate by the Passive House Institute in Darmstadt, Germany. It certifies the building has met Passive House criteria. Thus the new building, extension to the main building („base 1“) of kindergarten „Slantse“ in Gabrovo became the first certified public passive house in Bulgaria.


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Time period

Implementation time: 2 to 5 years

    Main benefits

  • Reducing GHG emissions

  • Decreasing energy consumption in buildings

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