More than 33 degrees are announced for May 18 in the Toulouse region, with a blazing sun. Sandrine Castanié was the guest of France Bleu Occitanie this Wednesday. She is the energy and environmental performance project manager at Envirobat, a group of professionals in sustainable construction and development.
Are Toulouse homes poorly insulated?
Housing is unevenly insulated. There are more efficient things, especially in more recent constructions, but there is indeed old heritage that can be more or less well managed.
We went on a report in the Cartoucherie eco-district in Toulouse, a very recent district in the west of Toulouse. And yet, the inhabitants tell us that they are hot. How do you explain it?
They are hot, of course. But it’s a notion that remains subjective, even if some of the interviewees also expressed a feeling of freshness. Yes, this is a problem that has not necessarily been in the crosshairs of the regulations, we have been very interested in the production of energy and the consumption of energy, heating, and less in this summer aspect. We will say that overall in the regulations, in the financial aid, they are not completely focused on this aspect. But it is increasingly taken into account.
We made a lot of mistakes in the past, on the insulation of buildings?
We are improving ourselves. We continue to insulate effectively to protect ourselves from cold and heat, that’s effective. On the other hand, what we have perhaps not done enough is to take into account the impact of these heat waves and solar protection, passive cooling strategies, ie without a complicated system.
This is taken into account in the new regulations for new buildings. But the regulations for new buildings only concern 1 to 2% of the real estate portfolio, which is renewed each year.
In the same way as the poor insulation of the cold, can we speak of energy poverty for the heat?
Yes, that is absolutely the case. In general, poorly insulated housing will react badly in winter and summer. What’s more, it will also be more exposed if there is no effective solar protection on the bay windows, if it is not possible to ventilate effectively at night to recharge the building with freshness.
What are the new techniques and new materials that are used to insulate homes today?
In renovation, there is a lot of demand for thermal insulation from the outside, which will prevent the mass of the concrete buildings from heating up, and which will retain inertia. So, this possibility of storing and destocking heat and coolness alternately between day and night.
With what materials?
It’s essentially polystyrene for now, let’s say. But we can also make use of bio-sourced renewable materials, therefore derived from living organisms, therefore which will not generate any long-term renewal problems. And then which will, inside or on the roof, participate in the phase shift, ie in slowing down the entry of heat into the premises since they will be denser. We can cite cellulose wadding, wood wool too, or even waste from rice growing, such as rice straw.
For a very high cost, or does it become affordable?
As it becomes more widespread, it becomes more and more affordable. The sectors settling and becoming consistent, we arrive at economies of scale which become more and more interesting.
At Envirobat, you play an advisory role with manufacturers. What do you say about air conditioning? Is it still current or do you really have to stop on this system?
Air conditioning does not completely solve the problem, since to cool its interior, we will throw heat outside, so we will participate in the warming phenomenon. In addition, this equipment works with refrigerant gases which emit greenhouse gases, so we are part of the problem.
So we are going to propose to favor all the passive solutions available. Good insulation, good sun protection on the glazing. Because unprotected glazing of one square meter is a small 500 watt radiator! So if we multiply the exposed glazed surfaces, we bring phenomenal heat gains inside the buildings. We will favor this natural ventilation. And then we will also play on the environment, avoiding minerality, and favoring the greening of outdoor spaces.