Four fire engines and around 25 firefighters were called to a fire at a house on Novello Street in Fulham.
A small part of the ground floor of a mid-terraced house and part of the electrical ducting from the ground to the second floor were damaged by the fire. A man, a woman and a male teenager left the building before the Brigade arrived. There were no reports of any injuries.
Sub Officer Rowan Logue from Fulham Fire Station, who was at the scene, said: "There was a lot of smoke billowing from the property when crews arrived.
"Due to the nature of the fire and the way it had spread up the electrical ducting, there was a lot of cutting away to allow firefighters to reach the fire and tackle it effectively.
"The family was alerted to the blaze by smoke alarms and the early warning allowed them to get out safely along with their three dogs.
"This incident is another reminder about the importance of having smoke alarms fitted in your home. You should have working smoke alarms in every room where a fire can start, plus a heat alarm in the kitchen and the bathroom. They should be tested regularly."
The Brigade was called at 0734 and the fire was under control by 0910. Fire crews from Fulham, Chelsea, Wandsworth and Hammersmith fire stations were at the scene.
The fire is believed to have been caused by a fault in a light switch.