Should You Use External or Internal Air Circulation in Winter?
2 Answers
Correct practice is to alternate between external and internal air circulation in winter. Brief description of air circulation modes: Internal circulation means the air conditioning system closes external air intake and only recirculates air within the vehicle cabin. External circulation means the air conditioning system opens external air intake to draw fresh air from outside the vehicle. Usage of air circulation modes: If the vehicle is fully occupied, it's necessary to periodically switch to external circulation to maintain fresh air inside the cabin, which also improves passenger comfort. Prolonged use of internal circulation during long drives can lead to oxygen deprivation in the cabin, potentially causing driver dizziness, blurred vision, and reduced concentration. Alternating between both modes accelerates the cooling/heating effects of the air conditioning system while maintaining clean cabin air and a comfortable environment.
Whether to use recirculation or fresh air mode in winter depends on the situation. When I first get in the car and it's freezing, I definitely turn on recirculation first - this way the heater only warms the existing air inside the car, making it heat up super fast. Once the cabin is warm, I switch to fresh air mode to bring in some outside air. The main reason for this is to prevent the cabin from getting too stuffy, which can make people drowsy and cause windows to fog up. During traffic jams, you must use recirculation mode, otherwise you'll suck in all the exhaust fumes from the vehicle ahead. On highways, you can use fresh air mode more often since the high speed provides good air circulation. Also, don't keep recirculation on when there are many passengers - too much carbon dioxide can cause dizziness. If you notice window fogging, immediately switch to fresh air mode with the defogger button - this works much better than just using the wipers.
