The deputy François Piquemal had gone to the residence of Ferrets, symbol for the parliamentarian LFI, of “furnace” buildings. He described the work carried out to better isolate the building from cosmetics. Jean-Pascal Agard, the renovation manager, defends his work with solid arguments.
In what state was this building before your intervention?
He was in a pitiful energetic state. The entire structure of the residence is made of steel, beams, posts, composite floors and metal siding on the exterior walls. The exterior carpentry is aluminum and sliding type. Heating was provided by electric heaters.
How do you explain these insulation problems?
This residence built in 1992 was the subject, at the time, of a construction experiment in a dry sector. The singularity of this configuration is a source of thermal discomfort in winter and summer that I had never encountered in my 33-year career. The metal coverings (sheets) of the exterior walls had very poor airtightness, generating hot drafts in summer (and… cold in winter) aggravated by worn joints in the sliding exterior joinery. There are gaps in the wall and attic insulation, etc. All these pathologies are the cause of high energy consumption for heating homes.
Qwhat jobs do you have TO DO realizeuh ?
All exterior walls and low floors have been strongly insulated from the exterior, thus considerably reducing surface losses and thermal bridges. The insulation of the attic ceilings has been reinforced and all the exterior joinery has been replaced by much more efficient windows and French windows. The heating and hot water production system by air/water heat pump for each dwelling has replaced the electrical transmitters and the cumulus in favor of very high energy performance. That made it possible to move from an energy label from E to B. More than a rehabilitation, it is a reconstruction.
p.or how much?
I find it unfair to call this rehabilitation “ cosmetic “. The cost is €68,000/housing invested by TMH… this amount is part of the “top of the basket” in terms of financial resources allocated by project leaders. At the level of the residence, the energy rehabilitation has allowed a theoretical reduction of 82% of consumption, with the significant increase in electricity costs, the savings on energy bills are very high.
How is it that we still observe such high temperatures despite your intervention?
More than ever, the behavior of the inhabitants has a considerable impact on the indoor temperature in summer. The slightest heat input from outside (windows open or shutters closed too late) or inside (cooking, iron, halogen lighting, etc.) is trapped in the accommodation thanks to the high insulation and contributes to the increase in the interior temperature. This is the current paradox, the various thermal regulations (in new buildings as well as in existing buildings) have focused on winter thermal comfort by increasing the thickness of the insulation and are only beginning to take an interest in comfort. summer thermal. For example, a resident who goes on leave by leaving the shutters open lets the sun’s rays enter his apartment, the heat is trapped by the strong insulation and the resident is not there to ventilate the night by opening all the windows. so that the air circulates in order to evacuate the heat stored during the day, this heat is then transmitted to the building through its structure.
Was-what good strategic choice to make in the south of France with global warming?
We are still in a temperate climate with well-marked seasons, the heating period lasts about 200 days, the periods of heat wave representing only a few days in the year… Our job consists in avoiding cooling or air conditioning as much as possible. . accommodation. The problem of high indoor temperatures also exists in new buildings when the scorching heat sets in for a long time.