Investigators tell Action News a neighbor went to check on the woman Monday in the 100 block of North 61st Street in West Philadelphia and found her in a bed on the second floor, dead.
The windows on the first floor were open and there were fans running.
However, on the second floor only one window was open a few inches and there were no fans.
Temperatures hit the upper 90s on Monday.
This is the fifth heat-related death in Philadelphia this summer, and the first of this heat wave.
