The “air recirculation” or “air recirculation” button is an important part of the air conditioning in your car, but its use may seem mysterious to some. So what exactly is it for and when should you activate it?
The air recirculation button closes the access to outside air and recycles the air already inside the car. This is a function that has several uses. First, it allows the cabin to be cooled or heated more quickly. Indeed, the interior air, already partially conditioned, consumes less energy to reach the desired temperature. Second, it’s useful for preventing the intrusion of unpleasant odors or outside pollutants, such as car exhaust on a congested highway.
However, it is important not to use the continuous recycling function. Recirculated air can be depleted of oxygen and loaded with carbon dioxide, which can cause drowsiness and headaches in car occupants. Also, the humid air generated by breathing can cause the windows to fog up, reducing visibility.
It is therefore recommended to use the air recirculation button mainly for rapid heating or cooling of the passenger compartment, or to avoid occasional exterior pollutants. But it is necessary to return to outside air intake mode afterwards to renew the air in the car.
There are situations in which the air recirculation should never be activated, in particular when there is frost or fog on the windows. In fact, the recycling of the air does not make it possible to demist the windows effectively, since it maintains the humidity inside the vehicle. To defog, it is best to use the heater with the outside air, which is generally drier.