Smoke alarms activated and alerted an elderly resident to a fire at a house in West Grove, Woodford Green.
Almost half of the ground floor of the two-storey terraced house was damaged in the blaze. One woman was treated at the scene for smoke inhalation.
Watch Manager Jim Tumini, who was at the scene, said: "This incident serves as a reminder of how important it is to have working smoke alarms fitted on every level of your home.
"The fire started in the kitchen and smoke alarms in the hallway and elsewhere in the house activated and alerted the resident.
"She discovered the fire, got out, called us and also alerted her neighbours. She did everything she should have done and fortunately got out before the smoke became quite thick.
"We know what the worst case scenario can be and without smoke alarms, this could have been a very different story.
"Smoke alarms give the earliest possible warning when a fire starts and we would urge everyone to make sure they have one fitted in every room where a fire can start except kitchens or bathrooms where heat alarms are more appropriate."
The Brigade was called at 0325 and the fire was under control at 0404. Four fire engines and around 25 firefighters from Woodford, Chingford, Hainault and Waltham Forest fire stations attended the scene.
The cause of the fire is under investigation.