Four fire engines and around 25 firefighters were called to a flat fire on Stopford Road in Plaistow.
Half of a flat on the ground floor of a converted end-of-terrace house was damaged by fire. Two people left the building before the Brigade arrived. There were no reports of any injuries.
The fire is believed to have involved a halogen heater.
A London Fire Brigade spokesperson said: "We would urge people to take extra care if they are using additional heating appliances to stay warm as there is a very real risk of people being injured by heater fires.
“Fires involving heaters can be easily prevented if people take some sensible, common sense precautions.
“Steps like keeping flammable items, such as curtains, blankets and furniture well away from heaters can make all the difference. It’s also important not to sit too close to them, especially if you’re likely to fall asleep as there is a risk of serious burns, and make sure they are turned off and allowed to cool properly before being moved or put away.
“There were a lot of possessions and clutter inside the house which made it challenging for firefighters.
"Hoarding means exit routes can become blocked, making self-evacuation more difficult. Fires can also spread much faster, especially when there are lots of flammable items such as newspapers or cardboard."
The Brigade was called at 0616 and the fire was under control by 0751. Fire crews from Plaistow, Stratford, East Ham and Leytonstone fire stations attended the scene.