Our homes are extensively impacted by current changes taking place in our society and the environment. I’d like to mention two particularly prominent examples—population aging and global warming—which will require radical transformation of our housing stock in order to adapt and meet these upcoming challenges.
We are living longer and so the number of elderly people (often living alone) is increasing. There is also a surge in demand for centrally located housing units that are adapted to the needs of seniors (not too large, easily accessible, and equipped to alleviate age-related loss of autonomy) or are connected to medical care. The topical concern around nursing facilities and, more importantly, the latest demographic figures highlight the need to find solutions in order to provide more living options for seniors, especially in their own homes. France’s first Baby Boomers, born in 1945, will be 85 in 2030. This 75 to 84 year old age group will register an unprecedented growth of 49% between 2020 and 2030, increasing from 4.1 million to 6.1 million people.[1]
In addition, housing is a major contributor to global warming. In France, it accounts for almost half of the country’s energy use and one quarter of our greenhouse gas emissions. Reducing these impacts entails curbing heating, cooling, and power needs through bioclimatic designs, zero-energy and well-insulated buildings, and equipping each unit with ultra-high-efficiency appliances while systematically resorting to renewable energy sources and innovative construction processes. As more than 90% of the multi-story buildings that will be standing in 2050 have already been constructed, their present and future renovation will have a major influence on the climate.
Let us add to this overview[2] that one in six housing units have very low EPC (Energy Performance Certificate) ratings of F and G (often referred to as passoires thermiques in France, i.e., “thermal sieves”), representing 4.8 million principal residences out of a stock of 29.7 million homes. If we refer to the tightened requirements from the Climate and Resilience Law of August 22, 2021, the numbers are even higher. Furthermore, the necessary energy efficient retrofit is not only confined to the most inefficient buildings given that, in 2018, at a time when the new rules on EPC ratings didn’t apply yet, only 2 million housing units achieved A or B ratings.[3] The transformation therefore concerns the overwhelming majority of private dwellings—a total of approximately 23 million housing units.[4] According to the generally accepted figures, upgrading an apartment to the current minimum energy efficiency standards requires investing a minimum of €15,000 to €20,000 (and double that amount for houses). Therefore, renovating all housing units concerned at an average per-unit cost of €30,000 would cost €690 billion in aggregate—a considerable amount in view of the figures for France’s building industry, and even more so compared to the annual €2 billion envelope announced for the MaPrimeRenov scheme. These elements cast doubt on the ability of individual homeowners and joint property owners to perform energy efficiency retrofits at the required scale.
Finally, I’d like to quote the latest IPCC (Intergovernmental Panel on Climate Change) report, from February 28, 2022, which alerts us on the increase in risk levels in cities, where half of the world’s population lives. Among the top threats, the experts highlight heat stress, which occurs when ambient temperatures exceed the limits of what the human body can withstand. The report therefore states that adapting to climate change in urban areas is critically important to the health and well-being of the majority of the world’s population. It advocates setting efficiency standards for buildings and rethinking urban planning, for example, by developing pedestrian areas in order to increase the effectiveness of the adaptation measures. It also considers that solutions such as tree planting, green roofs, and parks, all of which can help manage excess water flows from heavy rain events, are beneficial for human health when implemented at a large scale.