Four fire engines and around 20 firefighters and officers were called to a fire at a house in The Causeway, Sutton.
Part of the first floor of the property was damaged by fire.
Two people left the property before the arrival of the Brigade. There were no reports of any injuries.
The Brigade was called at 1807 and the fire was under control at 1903. Fire crews from Sutton and Mitcham fire stations attended the scene.
The cause of the fire is believed to be accidental and due to a cardboard box falling in front of an electric heater.