Paris. Following the publication in December 2023 of the Guidance and inspiration guide for the ecological transition Commissioned by former minister Rima Abdul Malak, the Ministry of Culture unveiled this summer the result of four workshops conducted by the Committee for Foresight and Innovation (CPI). The report “Heritage and architecture in the ecological transition” resulting from this work makes recommendations for heritage professionals on four major themes: training for ecological transition, “green conservation”, energy (mainly energy renovation) and digital technology. In these recommendations, the need emerges to adapt a certain number of standards, regulations and practices to reconcile heritage preservation and the climate emergency.
The question of the energy performance diagnosis (EPD) thus occupies a good part of this report, as this indicator of the energy consumption of a home crystallizes the tensions between heritage and ecological transition. For the CPI, the regulatory framework “today clearly leans towards thermal improvement, which poses a threat to heritage”. The cause is external thermal insulation (ITE), a solution now favored in renovations, which causes aesthetic and structural damage to old buildings.
Train diagnosticians
To restore the balance, the report recommends an adaptation of the DPE-3CL method (calculation method used by diagnosticians) in order to take into account the specificities of heritage buildings. “A weak development effort”, estimates the CPI: in fact, most of the criteria making it possible to objectify summer comfort or the inertia of traditional materials already exist in the diagnosticians’ software. Training the latter in heritage issues thus seems to be a much more effective lever than the creation of a calculation method specific to heritage, which would go against the equal treatment required by the European directive on energy performance. buildings.
It is also recommended that town planning documents integrate the issues of energy renovation, like the conservation and development plan for Angers currently being drafted.
If the part devoted to DPE largely takes up the recommendations of the G7 Heritage and the commission of inquiry carried out on the subject (and in particular the relaxation of the rental ban for poorly rated old housing), it does not mention the one formulated by the National Council of the Order of Architects. The latter wants to see architects become players in energy renovation, in order to develop sober climate solutions in buildings, such as natural ventilation or play on exhibitions. The orientation document prefers to mention another profession, that of “energy auditors”.
Preserve old joinery
Very eloquent on the regulatory framework, the report is a little less so on the major obstacle represented by the cost of energy renovations respecting heritage, much higher than exterior insulation: it barely indicates that the bans on Rental accommodation should be accompanied by aid, in what looks like a solution of last resort. The cause of old joinery, too often replaced by PVC double glazing, is widely defended in these recommendations, which rightly note that they rarely represent the main source of energy loss. The document, however, fails to mention the question of thermal bridges, these points of weakness in masonry which are sources of energy loss. They are much more present in old buildings, an element which also calls for intervention by architects in thermal renovation.
Regarding the reuse of materials, the report also lists a certain number of regulations to be adapted in order to allow the recycling of heritage materials: the lack of certification on these materials and the existence of obstacles in the general code of property of public figures prevent the generalization of recycling. For certain materials, such as lead, the CPI calls for “manage contradiction” between heritage interest and environmental issues: should we read implicitly a call for regulatory exemptions for heritage use?
Another object of attention is “green conservation” practices, such as the Epico method proactively implemented at the Palace of Versailles. This method favors maintaining “historical” conservation conditions, rather than controlling temperature and humidity by machines. A much more sober approach that has proven itself in terms of conservation of movable property. A workshop devoted to digital issues formulates very practical recommendations in the face of the problem of the inflation of heritage data and their storage. Finally, training in energy transition appears to be the first challenge for the heritage sector: in current university courses, the modules devoted to the subject are “more awareness than real training”is judged in the results of the workshop on this major issue.
