Why Airplane Cabins Feel Hot Before Takeoff
Why Airplane Cabins Feel Hot Before Takeoff
It often feels hot in the cabin before take-off because:
1. Air conditioning depends on the engines
On the ground, the main engines are usually off or at idle. Cabin air conditioning normally comes from bleed air taken from the engines. With engines not yet running, the system isn’t at full power.
2. Reliance on the APU or ground air
Planes have an Auxiliary Power Unit (APU), a small engine at the tail that provides electricity and limited air for cooling while parked.
In very hot climates, the APU sometimes isn’t enough to keep the whole cabin cool, especially if the plane has been sitting in the sun.
Some airports provide ground air-conditioning units, but not all of them are effective.
3. Doors closed, passengers inside
Once boarding is complete, the doors close, and fresh air circulation drops.
Hundreds of passengers inside produce body heat, raising the cabin temperature quickly.
4. Energy-saving practices
Airlines sometimes run the APU at a lower setting or delay starting the engines to save fuel and reduce emissions. That means less cool air until takeoff.
5. Sun exposure
Planes sitting on the tarmac act like a greenhouse. The fuselage heats up under direct sunlight, and the cabin can get several degrees hotter than outside.
FAQs
Why does the cabin sometimes feel hotter when the plane is full?
Because more passengers mean more body heat and humidity, which raises the cabin temperature quickly in a closed space.
Do newer aircraft handle pre-takeoff cooling better?
Yes, modern planes like the Boeing 787 and Airbus A350 have more efficient cooling systems, so they stay more comfortable on the ground compared to older models.
Can the crew manually adjust the temperature before takeoff?
They can, but cooling power is limited until the engines are running at full capacity.
Why do some airlines keep the cabin cooler during boarding?
It’s a strategy. By starting cooler, the cabin feels more comfortable once passengers are seated and doors are closed.
Does the weather outside affect how hot it feels inside?
Absolutely. On hot, sunny days, the aircraft skin absorbs heat, making the cabin warmer than the actual outdoor temperature.
