The system malfunctioned and started smoking, according to a statement her 10-year-old son gave police, WRAL reported.
>> Read more trending news
He said his mother opened the door to let the smoke out of the room, but as she tried to leave the room, she collapsed and lost consciousness.
A family member told WRAL that she was shocked and died.
Rocky Mount police told WRAL in a written statement the unit charged the area sending electricity through Pittman as she was trying to leave.
Investigators said she suffered from cardiac arrest.
Her 9-year-old daughter was also injured and was taken to a hospital in Greenville where the child died, WRAL reported.
WITN reported Pittman was living at the motel with four others. Pittman was with her son, daughter and one girl at the time of the incident. A fifth person living at the hotel wasn't there.
Pittman's son was taken to a hospital to be checked out and another girl was not hurt, WITN reported.
Building inspectors were called in to examine the ventilation unit, and police said they were going to look at the motel's code enforcement records, WRAL reported.
The Rocky Mount Fire Department gave WRAL a list of recent inspection reports. The inspector said the department had found common violations.