The U.S. Consumer Product Safety Commission said it was working with the fire department to confirm the cause, and trying to figure out if the make and model is one of the hundreds of thousands the agency has recalled due to fire hazards.
The family heard sizzling and cracking from the board and an electrical outlet before the fire started Friday, according to PennLive.
One person jumped from a second-floor window. Three other people were rescued by ladder.
"And it's all because of a hoverboard -- just a hoverboard," Charles Dominick, who was at his brother's home Saturday, told PennLive. "A family as good as them, they don't deserve this. They really don't."
A firefighter who was responding to the scene died Saturday after his vehicle was struck by a drunk driver.
Sales of hoverboards were banned after its unstable battery configuration were believed to be the cause of fires.
"We would ask if you are using these things and they are knock-off brands, please not use them," fire chief Brian Enterline said at a press conference Saturday. "We've seen too many fires and too many fire fatalities as a result of these hoverboards."
The Associated Press contributed to this report.