Firefighters manned the hoses under heavy rain, trying to put out a fast moving fire on the 2100 block of Jefferson Lane in Huntingdon Valley just after 4:30pm.
"When we got here, we had visible fire at the front door and heavy smoke in the attic area," explained Chief Ron Herwig.
The owners of the home were out of town, but relatives could be seen in tears outside of the charred house. They say a housekeeper reported hearing a loud bang. She quickly called relatives.
"The housekeeper called, and said she smelled smoke, "The TV is smoking. The TV is on fire,'" said Jane Gorberg.
The fire may have been caused by a lightning strike. Both the housekeeper and a family dog were uninjured.
In Radnor, lightning struck a tree, ripping off bark, before jumping to a house and igniting a small fire.
Firefighters arrived at the house in the 500 block of West Beechtree Lance and quickly extinguished the blaze.
A Lexus SUV was also damaged by falling branches.
No injuries were reported.
In Northeast Philadelphia, water poured through the vents on the third floor of an apartment complex on the Roosevelt Boulevard.
A half dozen unit suffered extensive damage, forcing renters to find shelter elsewhere.
"The bathroom roof was coming in," said Deandre Wiley. "It was crazy. I walked down the hallway and that was caving in."
The water damage at the apartment complex can be repaired, but the home damaged by fire in Huntingdon Valley was destroyed.
A definitive cause has not been determined. The fire marshal's office is investigating and answers are not expected for a couple of days.