A fire sparked by an airconditioning unit has put a hole through the roof of a training building at Parafield Airport.

Emergency services responded to reports of smoke seen coming from the Flight Training Academy on Kittyhawk Lane about 6:50 a.m. on Monday.

An airconditioning unit in the accommodation building for trainee pilots burst into flames that then spread to the roof.

Three men were asleep in the single-storey building at the time but smoke alarms woke them and they escaped the house safely.

Firefighters took about 30 minutes to contain the blaze.

Fire damaged part of the building and personal items were damaged by smoke.

Total damage was estimated at AU$500,000.