Why airplane cabins are kept cool: Comfort and safety factors
Many passengers wonder why the temperature on an airplane is relatively low. Those who enjoyed warm vacations in sunny countries feel this particularly acutely when they face the chill upon boarding the plane. Here's an explanation of why this happens.
While the plane is parked at the terminal, the cabin temperature is maintained by external air conditioning units connected to the fuselage through large, yellow tubes. An auxiliary power unit on board also cools the cabin before takeoff.
Pilots control the temperature
In the air, cooling is provided by the main engines, and the temperature is controlled by the pilots. Flight attendants can make slight adjustments, but larger changes require contacting the cockpit.
Although airlines have internal policies regarding temperature, there are no official standards on this matter. In 2018, a petition was submitted to establish such standards, but a decision is still pending. Currently, everything depends on the type of aircraft, the route, and the crew's decisions.
The onboard temperature is divided into zones, each with separate sensors. If a sensor is located near a heat source, it may cause the system to determine that the cabin is too warm, prompting a reduction in temperature.
Outside the airplane, the temperature can reach minus 58°F, so the aircraft insulates passengers from the freezing atmosphere. It is coldest near the doors, where the insulation is weaker.
Practical explanation of cool onboard temperatures
There is a practical explanation for why the temperature on board is kept relatively low: warmth and cabin pressure can lead to dizziness or fainting. In large aircraft with hundreds of passengers, the crew carefully monitors the temperature to ensure it doesn't exceed a certain level.
Besides physiology, a cooler cabin helps reduce odors. In a warm cabin, scents such as food or a neighbor's shoes become more intense. Higher temperatures activate odor molecules, potentially ruining the entire flight for passengers. A cooler atmosphere also helps reduce dehydration, which can be significant due to the dry cabin air.
That's why the crew wears warm sweaters—not just as a fashion choice but as part of the uniform designed for flying in cold conditions. Passengers should also bring a light sweater, socks, and a bottle of water. The most important thing is to dress appropriately for the conditions on the plane, not for the weather at the destination or departure location.
