
Whether to use recirculation or fresh air mode in winter depends on the situation: use recirculation mode for short trips and fresh air mode for long-distance driving. The two modes refer to: 1. Recirculation mode means the air conditioning system closes external air intake and only circulates the air inside the vehicle cabin; 2. Fresh air mode means the air conditioning system opens external air intake to circulate outside air. The functions of automotive air conditioning are: 1. To cool, heat, ventilate and purify the air inside the vehicle; 2. To provide a comfortable environment for passengers, reduce driver fatigue and improve driving safety.

In winter driving, I usually switch to the recirculation mode first to speed up warming up. It's like wrapping myself in a warm blanket, preventing external cold air from entering, allowing the heating system to warm up the cabin more efficiently. But experience tells me that using only recirculation for a long time can cause the air to become stale and lead to severe window fogging, especially when the air humidity is high. Once the car is warm enough, usually after about 10 minutes, I switch to the fresh air mode, which draws in fresh air from outside, preventing CO2 buildup, avoiding fogging, and improving air quality. Especially in congested areas or on smoggy days, the fresh air mode combined with the cabin air filter can filter out dust and pollutants. An additional tip is to activate the car's automatic air conditioning function, which intelligently balances both modes, making it hassle-free and ensuring a safe and comfortable drive.

As a young car owner, I'm accustomed to quickly warming up my car on cold mornings: right after starting the engine, I switch to recirculation mode, which significantly reduces warm-up time and gets the cabin comfortably warm within 5 minutes. Then I switch to fresh air mode because exhaled air in stationary conditions can easily fog up the windows. Maintaining fresh air mode while driving also helps reduce fatigue and prevents dizziness caused by stale air. I've also noticed that in snowy or rainy weather, fresh air mode defogs the windshield faster, while the automatic AC settings save me the trouble of manual adjustments. Regular checks on the cabin filter are equally important to keep the system running efficiently.

From a technical perspective, I understand the difference between recirculation and fresh air modes: recirculation reuses the cabin air to accelerate heating, while fresh air mode introduces outside air to prevent window condensation. Using recirculation at winter startup is correct, but switching to fresh air mode after temperature stabilization is more crucial as interior humidity buildup causes fogging. Recommended practice is 5 minutes of recirculation during initial warm-up, then primarily fresh air mode. Automatic climate control systems typically feature sensors to regulate this balance, combined with cabin air filters to remove pollutants. This approach not only ensures visual safety but also minimizes dryness discomfort. Regular HVAC system extends its service life.

Regarding health aspects, I prioritize air circulation inside the car during winter: first using the recirculation mode to warm up quickly, but switching to fresh air mode once warmed to introduce fresh air and prevent drowsiness or dizziness caused by rising carbon dioxide levels. If someone smokes in the car or there are allergens present, the fresh air mode helps dilute these impurities. During dry seasons, I use a humidifier or slightly open the windows to maintain comfort. In cold weather, this switching also saves energy as the system doesn't need to run at full power. It's advisable to set the air conditioning at a moderate temperature to avoid overheating and fuel wastage.

From an energy-saving perspective, I believe the rational use of internal and external air circulation in winter can reduce fuel consumption: initially using internal circulation to recycle warm cabin air reduces engine load and accelerates cabin heating; but later switching to external circulation maintains airflow, preventing excessive fan operation that wastes energy. An economical approach is 15 minutes of internal circulation initially, followed by alternating with 30% external circulation time. Enabling automatic climate control optimizes this balance automatically while also reducing fog-related heating demands, thereby indirectly saving fuel. Practicing this pattern in daily driving is both eco-friendly and ensures safe comfort.


