Torrelago is one of the largest residential districts in Europe. Located in the Spanish city Laguna de Duero, near Valladolid, it consists of 31 blocks of flats with more than 4,000 residents. The district is experiencing a green revolution, which is expected to be a model in Europe.

It is one of three location chosen by the European project CITyFIED, started in 2014, to redesign the envelope of the buildings. Its aim is to improve their energy efficiency and to replace the existing district heating with a biomass-based system. However, social acceptance has not been easy in this retrofitting project.

The Torrelago tenant Herminia Ferreiro, 58-year-old, was not so welcoming of the project. She voted 'no' in the community assembly that approved the retrofitting in June 2013. Although the project is co-financed through European funding and energy savings, she fears that her contribution to community expenses will increase.

"The tenants who are not convinced about the project are the ones who have not experienced its benefits,"says Isabel Martín Sanz, architect and expert in restoration and retrofitting buildings at project partner 3IA. "Showing energy savings is the most powerful strategy to convince people because in such big projects tenants need to experience the changes directly to be won over," adds Martín Sanz.

María Cristina Garcia Nuche is happy to live in one of the first flats to be retrofitted as part of the project. The region of Spain where she lives experiences extreme weather fluctuations. And the existing heating system and the old, uninsulated façade, were not sufficient to keep rooms warm on cold winter days. As a result, energy costs have been soaring. "With the new heating system, we can keep consistent temperatures the whole day and the temperature drop is far smaller now. In the morning it is not that cold," says García Nuche.

The Torrelago residents skepticism has taught Engineer Javier Martín Sanz, who works for Veolia, the Energy Service Company (ESCO) in charge of the district heating transformation, that that tenants have to be kept informed right from the very beginning of the process. "It would have been useful to have a permanent office in the district and to be in constant touch with the local press," adds Martín Sanz.

For this reason 3IA employed one of the neighbours, to man a temporary office to keep Torrelago residents informed on a daily basis and to address their questions.

Cultural differences also matter when it comes to acceptance of these housing changes. "In Spain we do not seem to give enough importance to the fact that these retrofitting strategies achieve a 75% reduction in greenhouse gas (GHG) emissions in these buildings", says Martín Sanz. He underlines that it would have been easier if the blocks in Torrelago were public or social housing, or if the project had been co-funded by local or regional government, as was the case in the other two demo-districts in Sweden and Turkey.

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