Donner House   Visby, Sweden

Donner House was s a former trade building and trading company, telegraph station and
telecommunications works, post office and post house.

In 2012 the ventilation system was improved with a new supply and exhaust system with heat recuperation. Additional energy optimizing measures were taken in 2017, replacing one exhaust ventilation. A renovation of the
facade, windows and roof has started, with the first phase carried out in 2020 and coming phases planned for 2023-
2025. This the building is currently in need of further energy optimizing measures, including e.g. solar energy
production, improved inner wall insulation, improved indoor climate and improved ventilation in terms of noise
disturbance and energy efficiency.
Visby, on the island of Gotland, was the main centre of the Hanseatic League in the Baltic from the 12th to the 14th
century. Its 13th-century ramparts and more than 200 warehouses and wealthy merchants’ dwellings from the same
period make it the best-preserved fortified commercial city in northern Europe. Buildings within the UNESCO site,
including Donner House, are all closely monitored in terms of preservation of historic value, hence all ambitions to
include PV panels within the roofscape of Visby have yet failed to meet the regulatory demands for preservation of
historic value. Similarly, energy efficiency improvement measures for facades and windows in listed buildings must be
highly invisible.

Le Locle & La Chaux-de-Fonds, Switzerland.

La Chaux-de-Fonds and Le Locle, located in the Jura mountains, have been jointly listed by UNESCO since 2009. The
historical manufacturing activity carried out in this region is linked to the watchmaking industry, and these towns were
designed, particularly after dramatic fires in the 18th century, according to this specific field of production, bringing
together private and public interests. The main concern during the reconstruction was fire prevention. To this end, the
buildings were constructed in such a way as to form isolated longitudinal masses. Roof covering with tiles became
compulsory. These two currently protected areas pose major problems in terms of building renovation. External
insulation of buildings is not allowed. Photovoltaic installations are only accepted under certain conditions. The local
councils, aware of the energy issue, are trying to reconcile the energy transition with the protection of heritage. The
Federal Office of Culture in Switzerland in promoting and encouraging this approach as a strategic topic. The objectives
in terms of production of solar energies in the 2 cities of Le Locle and La Chaux-de-Fonds has been fixed by the “ Plan
Cantonal de l’Energie”. The solar potential of Le Locle is estimated at 96.08 GWh/year and for La Chaux-de-Fonds at
277.90 GWh/year

Museum of Natural History, France

Museum of Natural History opened in 1855, situated in the city center of Grenoble with an average annual attendance in recent years of
around 80,000 visitors.
public. The building is made up of a large barlong element 70 m long and 12.80 m wide, 3500m2 sqm, made up of a front
central body on a portico. The entire building is covered in battière. The building has three levels.
The Museum, by its architecture and its urban positioning reveals the archetype of the monument
erected in celebration of the post-revolutionary ideals
resulting from a period of development and prosperity.
This neo-classical style is placed as official architecture. It
corresponds to the affirmation of public power and is very
clear in the same way as the major facilities designed
during this period: courthouses, hospitals, barracks,
theatres, museums…  According to the first evaluation the
current insulation is poorly implemented, leading to
important thermal bridges.