Energy efficiency in dwellings: it works! Retrofitting represents ¾ of French dwellings space heating consumption 2006-2013 decrease

Panel: 8. Monitoring and evaluation: building confidence and enhancing practices

This is a peer-reviewed paper.

Authors:
Céline Ilias, EDF – Recherche et développement, Dépt Energie dans les Bâtiments et les Territoires, France
Marie-Hélène Laurent

Abstract

Since 2000, a significant decline in dwellings Space Heating consumption has been observed in several European countries. The very fast decrease could suggest that its main cause is the change in households’ behaviours. This assumption is reinforced by the important increase of retail energy prices that has been observed during the same period.

Another important cause explaining this fast decline is the improving energy efficiency of the housing stock due to the refurbishment of existing dwellings.

An evaluation of cumulated savings due to the refurbishment of existing dwelling stock has been made.

Thanks to several national surveys, a compilation of the retrofitting actions conducted between 2006 and 2013 has been built. Nearly 3 million housing per year (principal residences) was affected (10% of the whole dwelling stock). Building insulation gestures were the majority of the retrofitting actions but the unitary efficiency (per gesture) was usually considered as low.

Three scenarios have been defined. We assume same annual number of retrofitting actions for the three scenarios. The differentiation between scenarios relies on the levels of “retrofitting intensity” (unitary energy savings per gesture): “pessimistic”, “neutral” and “optimistic”.

By 2013, the two realistic scenarios (pessimistic and neutral) give cumulated savings (2006-2013) close to the observed decline of the pre-2006 existing dwellings SH consumption. The pessimistic scenario is the only one stating lower savings (77%) than the observed decrease.

The 2013 French National Housing survey (Enquête Nationale Logement) is available since the beginning of 2017. Future analysis of the 2006 and 2013 editions will give precious information on the evolution of households’ behaviours during the same period. Further work will investigate if it could explain the 23% savings missing.