A plastic tray fell on to a cooker hob and melted, sparking a call to the fire service.
The cooker had been accidentally left on and set off the alarm in the foyer of the building in Woodhams Close, Battle, at 9.43am this morning.
A neighbour, who was alerted by the smell, investigated and found smoke inside the flat before dialling 999.
Hastings and Battle firefighters were sent to the scene.
The melted tray tripped the electrics, which saved the flat, which was empty as the occupier wasn’t home.
Now, East Sussex Fire and Rescue Service is warning of the dangers of leaving items on or near a cooker, even if switched off.
Crew Commander Jon Baker said: “We recommend that no flammable items are stored close to the cooker, however tempting this may be.
“People do this all the time but we would urge homeowners to take extra precautions in this area, as accidents do happen.
“We would like to praise the neighbour’s quick actions.
“The neighbour did exactly the right thing by shutting the door and leaving the building.”
“We would always urge homeowners to carry out relevant safety checks before the leaving the house, to ensure that everything is switched off.
“It is always best to switch the cooker off at the wall, so if the hotplate is left on it will be switched off.”