The record was 8,932 megawatts set back in August of 2006. The official number for Thursday wouldn't be known until a complete analysis is done.
Whether a record is broken or not, PECO spokeswoman Cathy Engel-Mendez said the system was performing well on Thursday, despite the high demand.
"We have been closely monitoring its performance as well as the weather conditions and we're very happy with what we're seeing performance-wise," Engel-Mendez said.
She added that extra crews were on standby in case any problems developed.
PECO recommends setting your thermostat between 75 and 78 degrees, but it depends on the home and those inside, such as the elderly.
We went to Facebook and Twitter to see what temperature Action News viewers keep their thermostats.
Jayne Wicklund wrote she keeps her thermostat at 68 and would have it lower, but her husband says no way.
Chris Burge told Action News, he tries to keep his at 78, just cool enough to keep the wife happy.
One good reason to keep it cool at night is that the heat makes people a lot more irritable because instead of cooling, the body overheats, disturbing your sleep.