Photo: Air recirculation in a car (Getty Images) Author: Konstantin Shirokun
If the entire climate control system in the car's interior is responsible for comfort, then one of its components – the recirculation function – directly affects safety. We remind you how to use it correctly.
Read about how the same button can help and harm in the RBC-Ukraine article.
The recirculation mode is not always activated by a specific button these days, and this name is somewhat arbitrary. It would be more correct to call this function a switch for air intake channels into the cabin – it turns out that a lot depends on this.
The operation of the climate control system of any car is based on the distribution of air flows throughout the cabin. In winter it is heated, in summer – cooled; in addition, it can simply be neutral in temperature. And filtered, if there is a filter, or dirty – if there is no filter at the inlet or if the owner (mechanic) did not insert it.
In all the cases mentioned, the car can take air either from the street or from the interior – and as we mentioned above, this circumstance is often fundamental. This is where our recirculation mode appears: this is a scheme when air for the heater, air conditioner or simply for ventilation is taken from the interior itself. (It turns out that under the influence of the fan, the air goes in a circle, which is where the word recirculation comes from).
When to use recirculation
It is advisable to activate the air recirculation mode in the passenger compartment:
- Stink ahead . If there is a car ahead whose exhaust pipe emits a lot of untreated exhaust gases. Here you should switch to air intake from the cabin in time so that the climate control system does not have time to suck in a portion of black exhaust. However, we note that this task of the recirculation system is not necessary for cars with carbon cabin filters;
- Dusty road. When the car is moving along a country road where dust is rising in a column, or, say, driving along a highway next to which agricultural machinery is working in a field, road repairs are underway, etc. Of course, the cabin filter will easily protect passengers from dust, however, by switching to air intake from the cabin, you can save the filter resource;
- Speed up the creation of a microclimate . The “outdoor air” mode will help if there is a need to immediately warm up the interior in winter or cool it down in the heat. So that the heater radiator does not have to heat up the frosty outside air, it makes sense to supply it with slightly warmed air from the interior. And this is what the recirculation button is responsible for. A similar picture is in the summer heat, when you need to cool the interior with an air conditioner. Moreover, some car manufacturers advise using the air conditioner only with recirculation activated. There is sense in such advice, but not always – the mentioned button also has a downside, which we will discuss below.
When Recirculation Is Harmful
In cold and damp weather, not only in winter but also in summer, fogging of the passenger compartment windows occurs in the recirculation mode – and then the driver loses visibility. On frosty days, fogging is also dangerous because the moisture on the glass can freeze, and the frost cannot melt quickly.
When air is taken from the interior rather than from the street, the windows will fog up faster if there are a lot of passengers in the car – and especially if they talk a lot or have recently consumed alcohol.
It happens that even with the recirculation deactivated, the windows fog up. The reason is a clogged cabin filter, which does not let the required amount of fresh air from the street through.
Keep in mind that windows fog up quickly and return to transparency much more slowly – and for this it is not enough to switch to air intake from outside. To speed up fogging, you need to turn on the air conditioner, and when it is not there, you should open a few windows. Often, the car has a button for accelerated fogging (intensive blowing) of the windshield. Together with the direction of a powerful air flow to the windshield, it automatically turns on the air conditioner, which dries the air and cleans the windows.
Short
Let us emphasize once again that recirculation is important for traffic safety. Therefore, even before using the car, the driver must understand both the direct activation of this function and the switching on/off of other modes that simultaneously control the intake of air from the street and from the passenger compartment. On the road, there are situations when the windshield can unexpectedly fog up and become opaque right on the move – and then recirculation must be turned on immediately. And on some models, so you know, for this you have to turn to the touch screen and look for the desired menu there.
Materials from Autocentre and Motor were used in preparing this article .
Let us recall that RBC-Ukraine recently reported on the types of all-wheel drive available on pickups and SUVs.