Why are planes so cold? Science explained
Many passengers wonder why the temperature on the aeroplane is relatively low. Those who have enjoyed warm holidays in sunny countries feel this acutely, as they have to face the chill upon boarding the plane. We explain what it's all about.
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. There is also an auxiliary power unit on board that 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 slightly adjust it, 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, the system may determine that the cabin is too warm and lower the temperature.
Outside the aeroplane, the temperature can reach minus 50°C, 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 odours. In a warm cabin, scents such as food or a neighbour's shoes become more intense. Higher temperatures activate odour molecules, potentially ruining the entire flight for passengers. A cooler atmosphere also helps reduce dehydration, which can be substantial due to the dry cabin air.
That's why the crew wears warm jumpers – it's not just a fashion choice, but part of the uniform designed for flying in cold conditions. Passengers should also bring a light jumper, socks, and a bottle of water. The most important thing is to dress appropriately for the conditions on the plane, rather than for the weather at the destination or departure location.
