What is at stake regarding Low Carbon Housing ?
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The results of the research project “ Low Carbon Housing ”, lead together by the Laboratory of Architecture and Sustainable Technologies (LAST) and the Building 2050 Research Groupof the Ecole polytechnique fédérale de Lausanne (EPFL), were presented in a seminar at the Smart Living Lab in Fribourg.
Entitled “LOW CARBON HOUSING. Environmental impact assessment of Swiss residential archetypes: a comparison of construction and mobility scenarios”, the presentation by Dr. Sophie Lufkin, scientist, Judith Drouilles, doctoral assistant, and Sergi Aguacil, doctoral assistant, has highlighted major issues related to the creation of low carbon housings.
The project aimed at producing reference data for assessing environmental impacts owing to renovation or construction of archetypal residential buildings in the Swiss context. The comparative evaluation of numerous scenarios highlights the importance of considering life cycle analysis (LCA) that include environmental impacts due to the dwelling use, as well as their construction and the induced mobility of their occupants.
Analysing current practices shows that the induced mobility alone is responsible for highest CO2 emissions than what require cumulated target values for construction, use and induced mobility set for 2050 (according to SIA 2040). Those results underline the importance to take into account buildings location and service quality in every study about energy transition of the built environment.
The results also highlight that significant improvements can be achieved through retrofitting buildings built in the post-war economic boom (1946-1979). In the best cases, heating energy needs can be reduced by 75% due to, among others, improvements of the thermal envelop.
The comparison between single-family houses and multi-family houses underline the best performances of the latter. Some scenarios of multi-family houses compatible with label MINERGIE-A® goals reach the intermediary targets of the “2000 Watts society”. On the contrary, results obtained per square meter of built surface are 20 to 30% higher in the case of single-family houses. This gap is even increased when results per person are considered, since this type of dwellings is frequently under-occupied.