What Do the Interior and Exterior Circulation Modes in a Car Mean?
2 Answers
Introduction to the interior and exterior circulation modes of car air conditioning: 1. Interior circulation means the air circulates only inside the car, driven by the blower to cycle the interior air. 2. Exterior circulation connects the inside of the car with the outside. While the car is moving, airflow automatically draws in outside air due to wind pressure. When stationary, outside air can still enter the blower through the air ducts and be blown into the car. Below are some scenarios regarding when to use interior or exterior circulation in car air conditioning: 1. When the outside air quality is poor, to prevent harmful gases from entering the cabin, set the system to interior circulation. 2. During long highway drives, to prevent a decrease in oxygen levels inside the car, alternate between interior and exterior circulation modes.
I've always found the air recirculation and fresh air modes in car air conditioning to be practical features. The recirculation mode means the AC only draws air from inside the car for reuse, closing the external air intake - perfect for quickly cooling down the cabin when first getting in during summer, or avoiding exhaust fumes from vehicles ahead during traffic jams. The fresh air mode draws in outside air, creating a refreshing breeze that feels great. My usual practice is: using recirculation for short city drives to save fuel, then switching to fresh air on long highway trips to maintain air freshness and prevent CO₂ buildup that could cause drowsiness. I remember once smelling something burning through the fresh air mode in a tunnel, and quickly switching back to recirculation to block the dust - so convenient. But don't overuse recirculation, as the cabin can become stuffy like a tin can. It's good to periodically open windows or switch to fresh air mode.
