Mur|Mur : Retrofitting private buildings to reduce energy consumption


Mur|Mur is a major private housing renovation scheme de-veloped by Grenoble Metropole. The first campaign aimed at reducing energy consumption through the retrofitting of condominiums built between 1945 and 1975. 4,467 dwellings in 84 condominiums were renovated, and in total 173 condo-miniums benefited from tailored support because of Mur|Mur from 2010 to 2014. The renovations resulted in 5,200 tonnes of saved CO2 emissions, which translates to savings of €135-250 per year.

The project focuses on the thermal insulation of private housing to make them more energy efficient and consequently reduce CO2 emissions. In France, there is a need for locally motivated retrofit-ting projects, such as Mur|Mur, as the only incentives available are national tax credit and 0% rate loans. Insulating old buildings well reduces tenants’ heating and hot water bills, which make up 73% of buildings’ energy consumption. The implementation of this project also contributes to the alleviation of fuel poverty; which remains a critical social concern in France due to high energy prices.

As Mur|Mur targeted private co-owned housing, one main challenge was to persuade co-owners to go through the process of retrofitting. For renovations to begin, more than the majority of the co-owners in the building must vote in favour of the construction, which can often lead to the prolongation of the project. Financial aid was a major concern for owners. Many of the families living in the buildings lacked the financial resources to renovate and depended heavily on the subsidies provided by the metropolitan authority and partners. In total, 1,161 households (only owners who lived in the retrofitted building were eligible) benefitted from an individual means-tested subsidy that could cover up to 90% of the renovation works. Nonetheless, the financial support was paid afterwards, which caused difficulties for a small number of families to pay their living expenses. The project faced the difficulty of stimulating the building sector and citizens to transition to low energy renovations. Furthermore, fin-ding enough workers to carry out the retrofitting of buildings proved challenging due to this economic sector’s low activity in Grenoble.

The most important lesson learned from this project is that the process of retrofitting requires the simplification of procedures and dedicated support to home owners. Following the assessment of Mur|Mur, a one-stop shop was established to provide direct admi-nistrative support to owners. Dedicated sessions for both co-owners and building managers have been implemented. These meetings aim at understanding residents’ feelings as well as to encourage them to overcome their fears about retrofitting by sharing their testimonies. As retrofitting depends on collective decision-making, these meetings are also crucial to increase support among owners.

Download the full case study

Grenoble Mur|Mur