UPDATED 07/15/11 10:37 a.m.

CHICAGO (CBS) — ComEd is stepping up its timeline for restoring electricity from the storm at the beginning of the week, with plans to get the lights back on for every customer later Friday.

But as CBS 2’s Susanna Song reports, that may not be the end of the issues. Now, a heat wave may throw a monkey wrench into their plans.

The heat, which is expected to set in on Sunday, could cause another round of power outages.

By 10 p.m., more than 95 percent of customers had had their power restored. Only about 15,000 customers remained without power, from a height of 868,000 following the Monday morning storm.

On Thursday night, some people had elected to check out of their homes and go off to hotels.

Sheryl Hennig was one of those people. She told CBS 2’s Kristyn Hartman her Woodstock house is on a well that needs power to pump water, and thus has been left unlivable.

“Once the water runs out, the well runs out, you can’t flush the toilet, you can’t run water, you can’t brush your teeth, you can’t do anything,” Hennig said. “And I haven’t cleaned out my freezer yet, so I probably have a mess to go home to.”

And Hennig isn’t alone. At the Holiday Inn Express in Algonquin, the phones were ringing off the hook Thursday night.

“Even today, we’ve still been getting people asking if we have any rooms available,” said hotel employee Satya Mehta.

Call Georjanne Mortensen’s stay nice timing. While she has training at the hotel, she’s missing the outage in Lake Villa.

“I’m happy that I get to stay here,” she said.

But her husband, Jim Mortensen, stayed home. He has to sit in a chair all day to listen for the generator for his refrigerator and make sure everything is running smoothly and quietly.

Mortensen is also watching the dog. And his house is also on a well, so without power to pump water, bathroom breaks require a bucket.

He regularly checks up on ComEd, whose officials say they will soon fix his neighborhood’s problems.

“They’re doing their job. They’re doing the best they can,” her said. “They’re working 16-hour shifts.”

ComEd says 850 of its own crews and out-of-state crews have replaced 50 miles of downed wire and 300 damaged poles since the storms Monday.

ComEd is projecting 99 percent of its customers who were affected will have power by the end of the day.

But what about that heat wave?

CBS 2 Meteorologist Mary Kay Kleist says a warming trend will begin this weekend, and by Sunday, temperatures will soar into the 90s.

ComEd is taking that possibility seriously, and have scheduled a brief talk at 1 p.m. Friday about the possibility of another outage.

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