The fire started around 3 a.m. Saturday on the unit block of Arch Street in Palmyra.
Arriving crews found flames shooting from the house.
The fire caused smoke and water damage to a second home, investigators said.
Firefighters had to call in neighboring departments to assist.
Officials said four people and a dog made it out safely.
The fire was placed under control around 4 a.m.
A cause of the fire is under investigation.