2023-11-19 07:00:15
At first glance, it only has advantages. Among the various solutions for insulating a home, heat-insulating paint is presented as a way of killing two birds with one stone. Not only do we repaint the walls of our home, but we also save energy. Simple as a brush stroke!
Commercial sites thus extol the supposed merits of thermal insulating paint, a mixture of paint, resins and different ceramic components. This painting was “created during scientific research by NASA before being commercialized”, says energy company Engie. But be careful, the affiliation with the prestigious space agency is far from being sufficient to prove the effectiveness of such paint, warns Étienne Marx, engineer in the building department of Ademe, the Ecological Transition Agency: “We must be careful when we propose to transpose an innovation. Initially, this paint was not intended to insulate buildings. » Moreover, producers of heat-insulating paint tell us that they do not use the same technology as that of NASA.
Against the sun and against the cold
In any case, a brand like Theotherm claims to be able to “save 2° to 4° in your home” by limiting heat loss through the walls. While Korund presents itself as a coating which allows “minimum bulk (2 to 3 mm) for exceptional thermal performance”. Enough to appeal to owners of a small apartment, reluctant to the idea of insulating using traditional, much thicker methods, which waste precious square meters.
The mechanism ? “The paint encapsulates small air particles, which allows for extremely low thermal conductivity. Residual heat is not transmitted to the support, explains Hugo Robardey, general director of Theolaur Peintures, which produces Theotherm. Produced in France, this paint is intended to be both insulating and reflective: “It reflects a large part of the sun’s rays, which allows less air conditioning energy to be consumed in summer”.
Theotherm paint can therefore be applied both to the exterior facades of a building and to the interior walls of the room, where it removes the impression of a “cold wall” while preventing condensation. “We can compare it to a survival blanket, which acts as a barrier against heat and cold”poursuit Hugo Robardey. We offer eco-responsible technology that improves comfort all year round. »
Paint is not an insulator
The Ecological Transition Agency, however, calls for caution. “You have to be careful about the vocabulary used. An insulator is a standardized product, which meets specific criteria. Such paintings do not meet this definition”alerts Étienne Marx.
Read also: Here are the good reflexes to avoid a scam when you want to renovate your home
Hugo Robardey says nothing else. “We are not claiming that paint can replace 30 cm of rock wool or polyurethane. Ideally, it’s better to do both!” However, he emphasizes that there is “situations in which it is not possible to provide thermal insulation from the outside, for example in a condominium”, while interior insulation would be more expensive. “The investment is not the same”, he adds. You still have to count on around 90 euros for 3 liters (8 to 12 m2), significantly more than for a classic paint – you also have to add the cost of labor.
Thinking at the building scale
” There is no miracle solution “, in any case points out Ademe: a thermal renovation must be considered globally, by analyzing the building as a whole, taking into account the heating system and the windows.
A paint or coating will never replace a global thermal renovation. “On its own, a paint will not significantly improve the thermal resistance of a wall, resumes Étienne Marx. It is not an alternative. But if we apply it in addition to another insulator, why not. »
Read also: MaPrimeRénov’: here are the three main changes to know for 2024
Used in industry
The paint seems more effective outdoors, to combat heatwaves. “A light-colored coating, which incorporates ceramic, will have a reflective effect and will keep the exterior walls cooler”continues the Ademe engineer. “In general, these paints are used in the industrial world, to prevent heat from penetrating into the building. »
In the west of France, several companies, such as Cool Roof or Enercool, also offer this type of covering.
What effect on the DPE?
The application of a heat-insulating paint, applied indoors, will not be enough to change the DPE, the energy performance diagnosis, also warns Hugo Robardey: “For the moment, it is not included in the diagnosticians’ software. But I hope for good news in the coming months. »
In their calculations, diagnosticians take into account an index, designated by the letter “R”, which takes into account the performance of the material and… its thickness. “It’s not 1 or 2 millimeters of thickness that will revolutionize insulation,” comments Thierry Marchand, building engineer and president of the CDI FNAIM, the Chamber of Real Estate Diagnosticians.
He too would rather recommend these paints outdoors. “It’s interesting for condominiums, for example to insulate the gables”supports Thierry Marchand. “Or to combat thermal bridges, where the cold penetrates the facade”, for example at the level of a concrete slab. However, he emphasizes that attacking the walls is rarely enough: “to exit a DPE F or G, you need thermal renovation at the building level”.
1700387053
#heatinsulating #paints #solution #thermal #renovation