The fire broke out around 2:00 a.m. on the unit block of Border Rock Road.
Police on patrol in the neighborhood spotted the fire and notified fire crews.
Firefighters arrived to fire showing through the roof and the rear of the house.
Crews then requested PECO to the scene of the fast-moving blaze.
So far, there were no reports of injuries and it appears the occupants made it out safely.
Investigators are trying to determine what sparked the blaze.