The body of the man was found by firefighters after the blaze in the house of multiple occupation in Beeches Road.
The fire happened on the evening of September 29 but details have only emerged today.
Firefighters called to the scene managed to contain the blaze to the apartment before it could spread to other flats in the three-story terraces house. They managed to put it out by 2am the following morning.
Fire investigators have since inspected the scene and confirmed the blaze was accidental, after being started by an electric heater. The fire spread to a sofa in the property.
The fire and police services have now handed the investigation to the coroner.