In offices, shops and even in private homes, the air conditioning is running at full speed during this heat wave.
Embarrassing, too polluting… It doesn't just make people happy.
Is its bad reputation justified?
How it works ?
Air conditioners consist of two parts, connected together in a closed circuit.
The first device, installed indoors and called the evaporator, will extract the hot air that is in the room.
This comes into contact with the refrigerant, then in a gaseous state.
This gas is compressed, in order to increase its pressure, which increases its temperature.
It then arrives in the "condenser" (the part of the air conditioner located outside), and this is where the heat is evacuated.
The refrigerating fluid, which has become liquid again, remains in the circuit, and is sent back to an “expander”, which reduces its pressure.
This leads to its evaporation.
This process causes a decrease in the temperature of the liquid, which arrives in the circuit of the evaporator and thus lowers the temperature of the part.
Read alsoSleep, food, clothing, work... Our guide to survival during heat waves
Why does it pollute?
Firstly because the refrigerant gas is a very powerful greenhouse gas.
If it does not normally leak out during air conditioning use - except when it leaks - emissions occur during manufacture, maintenance or at the end of life of air conditioners, reveals the 'Ademe (Ecological Transition Agency).
However, refrigerant gases have a warming power between 1300 and 3260 times higher than CO2, explains Greenpeace.
In addition, the air conditioning is very energy-intensive.
According to figures from the International Energy Agency, it alone accounts for 10% of the world's electricity consumption.
Another problem for the environment: air conditioning rejects hot air, which inevitably aggravates the feeling of heat in cities.
Does air conditioning make you sick?
In some cases, air conditioning can have health effects.
"The first danger is the temperature difference with the outside, so it must not be too cold", explains Judith Loeb-Mansour, general practitioner and author of "Adventures and misadventures of a country ".
Otherwise, it's a bit "like staying in the sun for a long time and then going for a swim in cold water: the body is not happy", she illustrates.
With air conditioning, the shock is obviously less strong, but the temperature difference can still weaken the body and lead to a cold or even, possibly, "cause discomfort, rather in people who are already weakened", continues the general practitioner.
The other risk, "is that a bacterium (notably legionellosis) develops in the water tank of the air conditioning", continues Judith Loeb-Mansour.
A danger, however, reduced if the installation is well maintained.
Air conditioning can have a final effect, for people who have sensitive ground: reinforce allergies.
“Insofar as it stirs air, if this air is loaded with pollen, it can actually have a small effect on allergies, it is not illogical”, estimates the general practitioner.
Read alsoIn La Défense, companies try to do without air conditioning “as much as possible”
What are the advantages ?
Air conditioning still has advantages in the event of high temperatures, “especially for the fragile, elderly, who have heart disease or are sick”, lists Judith Loeb-Mansour.
Because high temperatures tire the body.
“Having even a few cool moments helps you withstand the heat better,” she continues.
What alternatives?
There really isn't a miracle solution.
However, fans have a significantly lower ecological impact than air conditioners, points out Greenpeace.
Already because they do not use refrigerant but also because they consume twenty times less electricity.
Then there are the usual tips for cooling your home: keep curtains or shutters closed during the day to avoid bringing in the heat, ventilate during the cooler hours, hang a damp sheet in front of a window or a fan...