Should You Use Internal or External Air Circulation on the Highway?
4 Answers
Short-term use of internal air circulation is acceptable, but prolonged use can lead to passengers repeatedly breathing in the same stale air they exhale. Additionally, due to the car's good sealing, outside air cannot enter the cabin. Over time, this can cause passengers to feel fatigued and, in some cases, even pose a danger. Therefore, when driving on the highway, it is advisable to occasionally switch to external air circulation to help reduce fatigue. Extended Content: 1. Internal air circulation primarily recirculates the air inside the car. The advantage is that it helps maintain a cooler interior temperature and reduces the loss of cold air. However, the downside is that the air inside the car does not get refreshed, leading to stale air over time, which can make passengers feel tired. 2. External air circulation exchanges the air inside the car with outside air. The disadvantage is that some of the cool air inside the car may be lost, but the benefit is that it refreshes the cabin air, maintaining better air quality.
When driving on the highway, I flexibly choose between recirculation and fresh air modes based on the situation. Initially, if the weather is hot, I usually use recirculation to allow the air conditioning to quickly cool or heat to a comfortable temperature, as the high speed and strong wind make recirculation more effective. However, after about 20 minutes, I switch to fresh air mode to introduce outside air, preventing the buildup of carbon dioxide in the car that can cause fatigue and dizziness, especially during long trips where drowsiness can affect safety. At high speeds on the highway, the external air flows quickly, with less exhaust and better quality, making it suitable for fresh air mode. But if I encounter tunnels, traffic jams, or areas with heavy smoke and pollution, I immediately switch back to recirculation to prevent odors from entering. In winter, I can also use fresh air mode to defog the windows before switching back to recirculation to maintain warmth. The cabin air filter should be replaced regularly; otherwise, even fresh air mode can draw in dust. This alternating approach ensures both energy efficiency and safe, worry-free driving.
When driving on highways, I prioritize health and comfort, often using the external air circulation to introduce fresh air, which keeps the cabin oxygen-rich and refreshing, helping to avoid drowsiness. At high speeds, the external air quality is relatively clean, making external circulation very suitable. However, when it's too hot in summer, I first use internal circulation to cool down quickly. Once the temperature stabilizes, I switch back to external circulation for ventilation, avoiding prolonged stuffiness and dizziness. If there's dust, pollen, or polluted areas outside, I immediately switch to internal circulation to prevent allergies, especially when traveling with children, as air quality is crucial. In winter, external circulation helps defog the windows, ensuring clear visibility and safety first. Setting the air conditioning to automatic mode is the most hassle-free and ensures comfort—avoid sticking to a single mode all the time.
On the highway, I often use the external air circulation to save money and ventilate the car. At high speeds, the engine naturally aspirates, reducing the burden on the air conditioning and saving fuel. However, when there is a strong need for cooling or heating, I first turn on the internal circulation to quickly adjust the temperature, then switch to external circulation to maintain fresh air, preventing driver fatigue. The key is to switch regularly, for example, every 30 minutes, to avoid high carbon dioxide levels. If the external circulation is not effective, check if the air filter is clogged. On the highway, external circulation is the main mode, but switch to internal circulation during traffic jams to prevent pollution—simple and practical.
