Use Internal or External Air Circulation in Winter?

[Bridget]

Correct practice is to alternate between internal and external air circulation in winter. More information about air circulation modes: 1. Brief description: Internal circulation means the air conditioning system closes external air intake and only recirculates air inside the vehicle cabin. External circulation means the air conditioning system opens external air intake to bring in fresh air from outside the vehicle. 2. Advantages of alternating use: Faster cooling/heating effect of air conditioning system, prevents excessive carbon dioxide concentration and oxygen level drop in cabin (which causes drowsiness and affects driving safety), maintains clean cabin air quality and a good cabin environment.