Use Recirculation or Fresh Air Mode When Stuck in Traffic?

[DeIsabel]

When stuck in traffic, use the recirculation mode as it saves more fuel. Recirculation means the car's air conditioning system only heats or cools the air already inside the vehicle. Since the cabin space is limited, the air temperature can quickly reach the designed value in recirculation mode. In fresh air mode, the car's AC system introduces outside air into the cabin (called "air exchange"). With continuous inflow of fresh outside air, it takes longer for the cabin temperature to reach the desired level, consuming more electrical energy or fuel. Although fresh air mode improves cabin ventilation, extremely hot outside air makes it difficult to lower the interior temperature. This results in continuous compressor operation without effective temperature control, wasting significant fuel. During traffic jams, fresh air mode may also introduce toxic gases into the cabin, creating health hazards. While recirculation cools the cabin faster, the lack of air exchange leads to reduced oxygen concentration from repeated breathing, potentially causing fatigue and even accidents. The optimal approach is to use fresh air mode in areas with good air quality, then switch to recirculation during traffic congestion or extreme heat. Alternating between both modes represents the most suitable solution.

[OHannah]

During traffic jams, I most often use the recirculation mode to avoid sucking in the stinky exhaust fumes from outside. The air in city traffic is full of particulate matter and carbon monoxide, and using the fresh air mode would let those pollutants directly enter the car, affecting health and easily causing dizziness. I use recirculation to keep the air clean, and the air conditioning also consumes less fuel, since the cabin temperature stabilizes quickly. But don't keep it on continuously—after a long time, the oxygen inside decreases, and the air becomes stuffy. I switch to fresh air mode every 20 minutes or so to get a few breaths of fresh air, or simply open the window for a second and close it. Using recirculation on rainy days also prevents window fogging. In short, I recommend setting the mode before getting stuck in traffic.

[LeSadie]

Commuting in traffic every day is exhausting, so I'm used to using the recirculation mode! Turning on the fresh air mode feels like inhaling the gray exhaust fumes from the car ahead—the smell is disgusting and irritates my throat. Recirculation is much cleaner, the AC fan runs quieter, and it saves a bit of power. However, if there are many people in the car, the CO2 concentration can rise and make you feel fatigued. My solution is to distract myself with music and briefly switch to fresh air mode for a short while to let the air circulate, so I'm not stuck breathing stale air the whole way. Also, the cabin air filter needs regular cleaning—during traffic jams, dust buildup can clog it and reduce efficiency. Keeping these habits makes dealing with long queues much easier.

[LeMia]

From an automotive design perspective, it's recommended to use recirculation mode during traffic jams. The fresh air intake (external circulation) draws air from the front grille, directly introducing toxic exhaust fumes in heavy traffic. Recirculation mode filters interior air through the AC system, offering healthier, safer and more efficient operation while reducing extra engine load. The cabin air filter removes some pollutants, but remember to clean it regularly to ensure fresh air. The downside is prolonged recirculation may cause window fogging or high humidity. I typically adjust based on weather: primarily use recirculation on sunny days, switching occasionally in humid conditions to prevent visibility issues. This simple technique is highly practical.