Milan: deep renovation for significant energy savings

In the social housing building located at Via Fertinelli 16 in Milan, the inhabitants are enjoying a warm and comfortable winter thanks to the refurbishment work carried out within the EU-GUGLE project. In this five storey building owned by the Municipality of Milan, the tenants were living in a low quality environment because of the poor energy performance of the building envelope. To help improve housing conditions for the 154 households living in the dwelling, the Municipality of Milan, together with the University Politecnico di Milan decided to integrate the building into an ambitious renovation programme.

The building after the refurbishment.


Before launching the refurbishment process, a team of experts analysed the building’s structure to identify thermal bridges and select the best insulation strategies in view of maximising the benefits of the future renovation. Once an optimal refurbishment strategy had been defined, project partners were ready to launch the refurbishment work.

Implementing an ambitious renovation project

The renovation was divided into two phases. As the first part of the process was dedicated to the structural aspects of renovation, tenants had to be relocated during the construction process. This was a real challenge for the Municipality since this first phase lasted for four years. During that time, the insulation of the building’s walls and roof has been improved and the windows and doors have been replaced. Additionally, electric and water systems as well as heating and hot water systems have been refurbished and the building has been connected to the district heating network. Before allowing the tenants to return to their homes, thermostatic valves and heat metering devices have also been installed on radiators.

In February 2016, two years after the end of the first refurbishment stage, the second phase of renovation began. During this five-month stage, an innovative system enabling the use of heat recovered from mechanical ventilation exhaust air for domestic water heating through air to water heat pumps was installed in the building. In addition, solar panels were installed on the roof to cover part of the building’s energy demand.

Involving tenants: the essential third phase of renovation

Besides the technical aspects of the refurbishment work, tenant involvement was of crucial importance during the project. Lorenzo Pagliano, expert from the University Politecnico di Milano, explained that “When the tenants moved back into their dwellings after the first phase of refurbishment, some of them thought the ventilation system was not working because of the low noise of the newly installed system. As a consequence, many tenants installed adjunctive air extraction fans in their houses, causing problems to the functioning of the general ventilation system”. Organising meetings to explain the functioning of the newly installed systems and devices is thus a major task in each refurbishment project and represents the first guarantee to achieve significant energy savings.







In the Via Fertinelli 16 building, the renovation has reduced the building’s energy demand by seven, thus resulting in major improvements in comfort and sustainability. Following the success of this project, the Municipality of Milan is planning to renovate a primary school in the same area.