Should the Car Air Conditioning Use Internal or External Circulation in Summer?

[EliasLee]

In summer, it's recommended to first use the external circulation or open the windows for ventilation before switching to internal circulation. Many car owners habitually turn on the internal circulation as soon as they enter the car during hot summer days, thinking it will cool down the interior faster. However, this is incorrect because the inside temperature is higher than outside, making this approach less effective. Here are some relevant details: 1. External Circulation: This mode draws air from outside the vehicle, filters it through the air conditioning filter, and then circulates it inside the car via the blower. 2. Internal Circulation: This mode blocks the external air intake, recirculating the air already inside the car. Whether using internal or external circulation, exhaust gases inside the car will be expelled through the vents, so there's no need to worry about oxygen levels even when using internal circulation.