Should the Car Air Conditioner Use Internal or External Circulation in Winter?

[DeSpencer]

Car air conditioner internal circulation refers to the recirculation of air inside the vehicle, which allows the interior temperature to rise more quickly. However, this can lead to a decrease in air quality. External circulation, on the other hand, draws in fresh air from outside the vehicle, resulting in a slower rise in interior temperature. In winter, it is recommended to first use internal circulation to warm up the car and then switch to external circulation once the engine has warmed up. Here are some important considerations for using the car air conditioner: 1. Do not forget to press the A/C button. This button controls the air conditioning compressor. Many drivers are not familiar with it, but simply turning on the air conditioner without activating the compressor will not cool the car, even if the temperature is set to the lowest. 2. Pay attention to switching between internal and external circulation. If external circulation is left on continuously, hot air from outside will keep entering the car, forcing the air conditioner to work harder to maintain a cool temperature, leading to excessive energy consumption. Especially in areas with heavy air pollution, avoid using external circulation as it will bring polluted air into the car. On the other hand, continuous use of internal circulation, while energy-efficient, can reduce oxygen levels inside the car, causing drowsiness and affecting driver safety. Therefore, to balance energy efficiency and passenger health, make good use of the internal and external circulation switch. 3. Utilize the defogging mode of the air conditioner. During heavy rain, fog can form on the windshield, and many drivers may not know how to handle it except by wiping it with tissues. The defogging mode of the air conditioner can quickly resolve this issue by simply turning it on. When turning off the air conditioner, it is also important to note that after pressing the A/C button, the cold air from the air conditioner can condense moisture inside the car into water droplets, which may remain in the evaporator. If not addressed promptly, this can lead to bacterial growth and mold. To prevent this, remember to turn off the A/C button before shutting down the car, allowing the air conditioner to operate in ventilation mode to dry the moisture. 4. Replace the air filter regularly. The air filter is responsible for purifying outside air before it enters the car. If the filter is not replaced for a long time, it can lead to reduced cooling efficiency and unpleasant odors inside the car. Over time, the filter accumulates dust and debris, reducing airflow and cooling performance. Additionally, this can promote bacterial growth, resulting in foul-smelling air being blown into the car.

[McCarson]

I often encounter this issue when driving in winter, feeling the need to flexibly switch between recirculation and fresh air modes. When I first start the car, the windows tend to fog up, so I always turn on the fresh air mode first to let outside air in and defog the windows. This helps clear the view and avoid danger. Once the fog clears, I switch to recirculation mode, which allows the warm air to circulate faster inside the car, heating it up quickly and saving fuel—especially important on snowy days with poor road conditions. However, don’t keep it on recirculation mode all the time, as the passengers’ breathing can cause carbon dioxide buildup, leading to dizziness or drowsiness over time. I usually switch back to fresh air mode every 20 minutes to ventilate, ensuring safety first. Additionally, check if the cabin air filter is clean—winter air quality is poor, and a dirty filter can affect health. In short, adjust according to the situation, prioritizing safety and comfort. I always stick to this routine on long trips.

[StGabriela]

From the perspective of comfortable driving, I prefer to alternate between recirculation and fresh air modes for heating in winter. Starting with fresh air mode efficiently defogs the windshield for better visibility while bringing in fresher air to prevent stuffiness. After the temperature rises a bit, switching to recirculation mode helps maintain cabin warmth, ensuring stable heating and better fuel efficiency. During heavy pollution like smoggy days, use recirculation mode more frequently but don't exceed 30 minutes to avoid oxygen depletion. I also manually adjust fan speed and temperature settings via the central console to prevent excessive dryness that might cause throat irritation. Regular maintenance of the AC system is crucial - replace clogged filters promptly to enhance overall comfort. In short, small adjustments based on weather and vehicle conditions make a big difference.

[JakeMarie]

In winter when using the heating system, I don't recommend keeping the air recirculation mode on continuously. With many passengers in the car, carbon dioxide accumulates quickly from breathing, which can easily cause drowsiness or dizziness. It's best to switch to fresh air mode periodically, for example every 15 minutes of driving, to bring in fresh air - this also helps with window defogging. For short trips, turning on fresh air mode shows immediate effect. Maintaining air circulation is essential for driving safety, especially when transporting children or elderly passengers. Developing this simple habit makes driving more comfortable and secure.

[TimothyAnn]

I've tried fuel-saving air conditioning in winter and found that using the external circulation to defog for a few minutes before switching to internal circulation for insulation is most effective. Internal circulation heats up faster and reduces engine load, but it's important to switch to external circulation promptly when fogging occurs. Switching to external ventilation before parking ensures fresh air. This method saves fuel in cold winds while enhancing comfort and preventing excessive dryness inside the car. Regularly checking the air conditioning ducts for smooth operation also helps with efficiency—I usually have it inspected once at the beginning of winter.