Between Trento and Lake Garda lies the Valle dei Laghi, one of the most distinctive yet lesser-known areas of Trentino. Its evocative name aptly describes the area’s character: here, water has always shaped life. Lakes such as Cavedine, Toblino, Santa Massenza, and Terlago were formed over the centuries by repeated glaciations, landslides, and floods, and they are what give the valley its distinctive character today. The hydrography of the valley is still characterised byglacial lakes, which are used not only for irrigation, but also for generating hydroelectric power.
The area’s social fabric has also undergone profound changes in recent decades. In the past, visitors would have seen small mountain communities where residents still shared the ground floor with their animals and stored hay in ventilated attics. Today, these villages are steadily evolving. Agriculture continues to play an important role, with vineyards, orchards, olive groves, vegetable gardens, and even small modern livestock farms appearing in the valley that opens up just beyond the narrow Bus de Vela gorge. Tourism is becoming increasingly important, as is the highly sought-after local craftsmanship.
All of this contributes to the tranquil atmosphere of the area, which is dotted with castles and fortresses from World War I, creating the impression that time has stood still. But this is an illusion. As in the rest of the Alps, the climate here has changed profoundly over the years — and this is well documented. “Historical data series show a significant rise in temperature since 1974,” explains Eleonora Leonardi, civil engineer and researcher at Eurac Research in Bolzano. “In particular, data from Torbole, Cavedine, and Santa Massenza have enabled us to observe the development of important variables such as temperature, humidity, wind, solar radiation, and precipitation over time.”
Leonardi is a researcher in the “Energy Renovation of Historic Buildings” group at the Institute for Renewable Energy at Eurac Research. The South Tyrolean institute’s contribution is part of IMPETUS, a European project funded by the Horizon 2020 programme that aims to strengthen the climate resilience of the Union’s regions. The Valle dei Laghi was selected as a demonstration site for mountainous regions and is one of the project’s seven pilot ecosystems.
When climate change is mentioned, the public usually immediately thinks of glaciers shrinking year after year, or of winters with little precipitation and low temperatures only at high altitudes. However, there is another, less visible aspect that affects both the preservation of architectural heritage and the quality of life in a changing climate.
Most of the historic buildings in the Valle dei Laghi date back to the 18th and 19th centuries. In the old town of Calavino, for example, an estimated 84% of the houses were built before South Tyrol was incorporated into Italy. These are buildings that were designed in pre-industrial times with thick walls, ventilated attics, and small windows to retain heat during the long Alpine winters. Today, however, it is precisely these characteristics that pose a problem. In summer, indoor temperatures quickly rise above comfortable levels, making the rooms uninhabitable for weeks on end.
As Leonardi emphasises, the data collected by Eurac as part of the IMPETUS project is used to define adaptation strategies that consider the buildings’ historical value. “The goal is to understand how they will behave in the future climate and what solutions we can develop,” she says. “Of course, we also take into account legal requirements, energy needs, and quality of life.” Essentially, simulations based on historical data enable consumption and comfort to be predicted until the end of the century. The project’s reference building, the former Bortoli house in Calavino, dates back to the early 18th century.
Thismulti-storey stone building has vaulted cellars on the ground floor, an apartment on the first floor, and a once-ventilated attic that used to serve as a hayloft, recognisable by the small round openings in the façade. With its wooden roof and stone window frames, the building is a prime example of Trentino’s rural architecture from that period.
Simulations by Eurac show that buildings such as the former Bortoli house experience critical conditions in both summer and winter. In summer, indoor temperatures often rise above 25 °C, exceeding the comfort threshold. In winter, despite the milder climate in recent years, heating requirements remain very high due to heat loss. Added to this are humidity and condensation problems that affect both the building’s structure and the indoor environment.
According to Valentina D’Alonzo, senior researcher at the Institute for Renewable Energy at Eurac Research, this is primarily a question of investment efficiency. “When planning measures for historic buildings, the current climate is still too often taken as a basis. But in twenty years’ time, we could find ourselves in completely different conditions.”
The measures proposed by the project therefore include internal wall insulation, roof and ceiling insulation, replacement of windows with double glazing, and installation of controlled mechanical ventilation. In addition, simpler solutions were also considered, such as night ventilation and using roller shutters or curtains to shield the house from the sun during the hottest part of the day. While these measures may seem marginal, they enable a significant reduction in heat stress during increasingly hot summers and thus contribute to ensuring the long-term use of historic buildings.
To evaluate these adaptation strategies, the researchers created a digital 3D model of the former Bortoli house replicating its geometry, materials, and use. Using WUFI Plus software, they simulated the building’s behaviour in seven future climate scenarios and analysed consumption, comfort, and humidity. Unlike static models, WUFI allows the distribution of heat and humidity in the rooms to be tracked over time. The results show that, when combined, these measurescan significantly reduce consumption and improve thermal comfort.
In addition to the technical aspects, the IMPETUS project has sought direct exchange with the region from the outset. “In the course of the project, various meetings and workshops were organised with public administrations, farmers, irrigation consortia, and industry representatives,” concludes D’Alonzo. “In practical terms, we have tried to communicate climate data in a way that is useful to those who have to make local decisions. […] We don’t just want to study, we want to provide tools that are really useful to the people who live in and manage these places.”
This article was originally published on Klima Land in Italian and German.
