Should the Car Air Conditioner Use Internal or External Circulation?
3 Answers
Whether to use internal or external circulation in a car's air conditioning system depends on the situation. Generally, when turning on the air conditioner for cooling or heating, you can first activate the internal circulation to quickly lower or raise the temperature inside the car. Once the temperature stabilizes, it's advisable to switch to external circulation to allow fresh air from outside to enter. Below are the details: Internal and External Circulation: The air intake for internal circulation is inside the car, meaning outside air cannot enter, and inside air cannot exit. The air intake for external circulation is located below the front windshield wiper, at the junction of the windshield and the engine hood, drawing in outside air. The Difference: The most noticeable difference is in air freshness. With prolonged use, internal circulation can lead to stale air, reduced oxygen levels, causing discomfort, fatigue, anxiety, and affecting driving safety. External circulation ensures airflow between the inside and outside of the car, preventing excessive carbon dioxide concentration.
When using the air conditioning, I usually prioritize energy efficiency by first turning on the recirculation mode to quickly cool or heat the cabin. This way, the AC system doesn't need to heat or cool outside air, saving a significant amount of fuel. However, prolonged use of recirculation can make the cabin air stuffy, so I switch to fresh air mode every ten minutes or so to allow ventilation. If the outside air quality is poor, such as during heavy traffic with exhaust fumes, I maintain recirculation to avoid pollution. When cruising on highways, fresh air mode is also suitable because the high-speed airflow provides natural ventilation. In short, learning to switch modes according to the situation makes the AC more efficient and durable while saving fuel costs. I always handle it this way when driving.
As a frequent driver who often travels with family, health and comfort are my top priorities, so I pay special attention to air conditioning usage. I mainly use the fresh air mode (external circulation) to introduce outside air, ensuring sufficient oxygen levels inside the vehicle to prevent children from feeling dizzy or uncomfortable. However, during high pollen seasons or in areas with heavy roadside smoke, I switch to recirculation mode to reduce allergy risks. During normal driving, I maintain the automatic climate control's default settings, which helps balance comfort and health. On long-distance trips, I alternate between fresh air and recirculation modes to prevent fatigue and reduce odor accumulation, making the journey more pleasant and relaxing.
