Four fire engines and around 25 firefighters were called to a fire at a semi-detached house split into maisonettes on The Crescent in Harlington.
Part of a ground floor maisonette was damaged by the fire. There were no reports of any injuries.
The Brigade was called at 0841 and the fire was under control by 0921. Fire crews from Heathrow, Hayes, Feltham and Hillingdon fire stations were at the scene.
The fire is believed to have been electrical.