Is it better to use internal or external circulation when turning on the air conditioning?

[McSimon]

It is better to use external circulation when turning on the air conditioning. The air conditioning system has two circulation modes: internal and external. Here is relevant information about internal and external circulation: 1. Internal circulation means the air inside the vehicle is recirculated, i.e., the air from the vents comes from inside the cabin, which is sealed and not connected to the outside atmosphere. External circulation means outside air enters the cabin, so the air from the vents comes from outside, and the cabin is not sealed. 2. Internal circulation only involves air blown by the fan circulating inside the vehicle. Since no outside air is involved, it saves fuel and cools (or heats) faster, but the downside is that it does not refresh the air inside the vehicle. External circulation means the fan draws fresh air from outside into the cabin, which improves air quality inside the vehicle, but cooling (or heating) is slightly slower and consumes more fuel.