Winter Car Air Conditioning: Use Internal or External Circulation?

[McMadison]

When using car air conditioning in winter, first activate the internal circulation to allow the entire vehicle to reach the target temperature, typically taking about half an hour. After half an hour, switch to external circulation for ventilation to maintain fresh air entering the car. Below are relevant details: Alternating Use of Internal and External Circulation: In most cases, when people turn on the air conditioning, they worry that external circulation will blow out the cold air from the car, consuming more energy. Therefore, even during long-distance driving, the internal air can become more stagnant, and prolonged use may lead to dizziness or hypoxia. When the air conditioning is first turned on, always start with external circulation. After the temperature drops, switch to internal circulation. Subsequently, alternate between internal and external circulation periodically—don't just turn on the air conditioning and leave it. No Need to Turn on the Air Conditioning Immediately After Entering the Car: After sitting in a car that has been exposed to the sun, many car owners can't wait to turn on the air conditioning to lower the temperature inside. However, immediately activating the air conditioning upon starting the engine increases the load on the engine. If this practice continues long-term, it can harm the engine. The correct approach is to open the doors and windows to let the hot air escape. Once the temperature inside and outside the car is similar, close the windows and turn on the air conditioning to release the accumulated warm air inside the car.