By Marie Jamet


If you like Hayao Miyazaki, Visby’s buildings might look familiar. This fortified medieval town on Sweden’s Gotland Island inspired the director of Kiki’s Delivery Service. But no magic can help Visby heat its historical buildings while preserving their beauty—especially as Sweden pushes for net zero emissions by 2045.

Despite the climate getting warmer, Swedish winters remain harsh and see surges in electricity demand with peaks throughout the day, generating power issues in Gotland County, explains Gustaf Leijonhufvud, a researcher in conservation at Uppsala University Campus Gotland and local INHERIT coordinator. Sweden’s energy mix has shifted since the 1970s oil shock, but decarbonising domestic use is still critical. “It is still very important to lower the energy use in buildings because society needs to electrify transportation and industry,” Leijonhufvud says.

The task is even harder in Visby, where strict UNESCO and national rules protect its 30-year World Heritage status.


The old and the new: how technology helps inherited buildings live in our times

Local authorities are actively addressing this issue, including through the EU-funded INHERIT project, which aims to preserve, restore, and manage historical buildings using science, technology and community engagement. “We want historic buildings to be more than relics of the past. They should actively contribute to social well-being, environmental sustainability, and local identity” explain Stamatia Rizou, INHERIT project coordinator and Antonia Vronti, project manager. “By combining advanced digital technologies, such as AI, IoT, and Digital Twins, with deep engagement of communities and stakeholders, we can create solutions that are tailored, practical, and socially accepted, while respecting the unique character of each heritage site.”

In Visby, research is underway at Kulturrum, a medieval building hosting creative workers and performance halls. The project uses DREEM (Dynamic high-Resolution dEmand-sidE Management model), a Greek-developed algorithm that collects internal data (inhabitants’ behaviour and building specifications) and external data (weather data and climate models) to suggest usage scenarios and retrofitting recommendations if relevant.

The system leverages the building’s natural inertia, biomass heating, and modern ventilation for data-driven management. Leijonhufvud illustrates: “The heating and ventilation can be turned off after office hours. The heating can then be turned on during the night to pre-heat the building. The users will still have a comfortable indoor temperature when they arrive in the morning but heating during peak levels between 7 and 9 am has been avoided.”

To feed the model with various internal data, starting in September, a dedicated researcher will work to make a typology of all historical buildings in Visby. "It is not a typology based on architectural style but on many other parameters that are more important" to the model, Leijonhufvud says.

These solutions help minimise invasive retrofitting, maintaining the fragile equilibrium of historical sites: preserving the city’s cultural character, everyday life and economic appeal without becoming a tourists’ museum city.

Stefano Musso, Full Professor of Architectural Restoration at the University of Genoa and Chair of the Architects’ Council of Europe (ACE) Heritage Working Group, emphasises: “In order to intervene on a building belonging to cultural heritage, some real and specific competences are needed. We have to save the most we can, because the matter of the building is the vehicle through which the values that are embedded in the building can be transmitted to the future”, noting that heritage buildings also encapsulate CO2 and avoidable waste.

Smartification can guide decisions, such as alternatives to solar panels—traditionally forbidden in Visby’s old city. Louise Hoffman, UNESCO coordinator for Visby, highlights public involvement brought by the project: “INHERIT has helped because it has a lot of social labs where we interact together. The public is involved.” As Rizou explains, this social pillar “relates to the engagement of local communities and stakeholders in order to co-create and shape together sustainable pathways for the cultural heritage built environment”.


When tourism has an indirect impact on energy savings

Hoffman confirms that Visby has not reached the tipping point in terms of mass tourism. Yet, tourism already has effects: housing prices rise, tourist beds increase, the population ages, and services leave the old city centre.

As a study published in June 2025 shows, this shift in city usage can lead to higher rebound effects, showing that energy retrofits, though necessary, may inadvertently boost non-essential amenities like air conditioning, increasing overall consumption.

To walk this thin line, INHERIT aligns with The New European Bauhaus (NEB) initiative, endorsed by cultural organisations in the 2024 Kraków Declaration. ACE’s Musso explains NEB is the heir of the 20th century Baukultur, a “holistic practice that has to answer the needs of humankind in terms of space of dwellings, of space to work on in an environment” and of the 1st century Vitruvius’ principles “called, in Latin, ‘firmitas, utilitas and venustas’ meaning stability and strength, useful and beautiful [...] but because the world changed a lot in two thousands years, now we speak about beauty, togetherness and sustainability.”

At INHERIT, “Partners were asked to position themselves on how their pilot is aligned to each of these principles together: beauty, sustainability and inclusion. This is something that we did from the very beginning”, explains Rizou. This way, “we can simultaneously address technical, environmental, social, and cultural dimensions in a way that traditional conservation practices cannot. Ultimately, we are striving to make heritage living and sustainable,” adds Vronti.

After all, as Musso puts it: “We are not the owners of heritage buildings — we are only transient inhabitants of the earth who have the duty to pass them on." While Visby’s efforts may work without Miyazaki’s magic, they offer a practical path for heritage buildings to thrive in the 21st century.