Plug-in wall heaters raise a range of safety concerns and are not considered safe by default. However, they can be made safe to use if certain precautions are taken.
Wall heaters should not be placed close to combustible items, and there should be at least 3 feet of open space on either side of the heater. To minimize the fire risk, extension cords should not be used with wall heaters. Plug the heater directly into the wall.
When purchasing a wall heater, check for additional safety features such as automatic shut-off in the case of the unit’s overheat. As with all electrical equipment, keep the heater away from water and dampness.