For many years, France has supported a policy of thermal insulation and airtightness in buildings, notably through successive thermal regulations (RT2012, etc.) and now environmental regulations (RE2020) for new builds. But what are the invisible consequences of this policy?

Energy consumption in France and in buildings

At France, the building sector accounts for 43% of the energy consumed in France , or 1.1 tonnes of oil equivalent per year per inhabitant, well ahead of the transport sector (31.3%). Every year, the building sector emits over 123 million tonnes of C02. This makes it one of the top priorities in the fight against global warming and the energy transition.

The breakdown of energy consumption by use in a primary residence is described above. It should be noted that heating accounts for 62%.

Heating and air-conditioning are therefore responsible for the highest energy consumption in the country's most energy-intensive sector. Together, they account for between 20% and 25% of France's energy consumption across all sectors.

Thermal insulation in France

To respect the European and international commitments, the public authorities have acted with the various successive thermal regulations, making all new buildings that respect them more and more "airtight". Even if the need to insulate is obvious, there are other ways to reduce energy consumption substantially, and for a much lower cost than insulation! The most important thing is to implement a plan of progress.

10 to 30% of the energy saving potential can be realized only through the awareness of the occupants to good practices for example.

Thermal regulations are mainly applicable to new construction and even to major renovations, whereas tax incentives are designed to support renovation. In the residential sector, for example, building insulation accounts for approximately 70% of energy renovation work, compared to 30% for work on heating systems (source: ADEME).

This leaves very little room for optimizing ventilation systems, but energy renovations remain a good opportunity to integrate Indoor Air Quality monitoring into the building. Or even improve its energy efficiency. Indeed, as we will see later, insulation greatly increases the risks related to the Air Quality. And if the latter is used to control the ventilation systems, it can increase the energy efficiency of the building tenfold while improving the health, comfort and productivity of the occupants.

The more airtight a building is made, the more its occupants will be exposed to sources of indoor pollutants (materials, human activity, ..), but not only! The external pollution can always penetrate in a building which does not have effective and maintained filtration systems. Moreover, there is a phenomenon of accumulation in an "almost airtight" space which only accentuates the exposure to harmful pollutants without adequate air renewal.

It is extremely easy to imagine this phenomenon by imagining that our modern ships look more and more like "submarines". It turns out that in these environments, the air is extremely controlled and renewed, otherwise the crew would be in a very bad position.

The main problem with Air Quality is that it is invisible, imperceptible and that one cannot be aware of its exposure without measuring all the relevant parameters.

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