Successful refurbishment of a residential building in Bratislava

Solar panels on the roof of the Bratislava buildings is one of the components of the innovative heating system.


In Bratislava, EU-GUGLE project partners have successfully achieved the renovation of a residential building located on Pavla Horova 17-19. The refurbished building was built in 1988 and is home to 42 households. Because of poor insulation, the energy consumption of the building was very high and the inhabitants had to bear substantial energy costs. To improve the comfort of the inhabitants, the Slovak Green Building Council and the Building Testing and Research Institute of Bratislava decided to renovate this building in the framework of the EU-GUGLE project.


“In Slovakia more than 90% of the apartments are owned privately, meaning that for each building, a multiplicity of actors has to agree on the refurbishment. In this context, owners’ involvement is thus a major challenge for the success of sustainable renovation programmes.” says Roman Grünner, leader of the refurbishment process in Bratislava within the EU-GUGLE project. In the Pavla Horova owner-occupied building, the first step was therefore to convince owners to invest collectively in the refurbishment. After six fruitful meetings, the owners appointed a Refurbishment Committee in charge of deciding what energy-efficient measures should be implemented. Six meetings of the Committee later, the renovation was ready to begin.

Façade of the refurbished building


Between July 2015 and March 2016, the building has undergone deep renovation work including the improvement of the external insulation of the roof, walls and basements. In addition, triple glazed windows have been installed and the balconies have been glazed. To improve the energy efficiency of the building, an innovative heat recovery ventilation system has been set up in each dwelling during the second part of the process that began in September 2015. Additionally, a new heating system has also been installed to make the best use of the energy distributed in the building.

Four innovative air to water heat pumps are located in the basement


Heat pumps as energy multipliers


The innovative heating system set up in the building is made up of a cascade of four air to water heat pumps located in the basement. These new heat pumps need only one third of the electricity they produce for space and water heating, thus allowing the buildings’ inhabitants to achieve significant energy savings. Each heat pump can produce more than 15kW of heat per hour and the system is partly powered by solar panels with a capacity of 10kW placed on the roof of the building. As a result, almost two thirds of the energy consumed in the building is now coming from renewable energy sources.

The heat recovery ventilation system.


Since the end of the renovation in January 2015, the owners are now using 80% less energy than before and CO2 emissions have been cut by 70%. Following this successful example, the city of Bratislava intends to renovate another building located in the city centre to further promote the implementation of energy-efficient solutions as well as renewable energy generation in owner-occupied buildings.