The increasingly chilly nights are a source of stress in thousands of households in the Merrimack Valley, which lost their source of heat more than a month ago when natural gas fires and explosions erupted across three communities.

On that September evening, Kelsey Grondin and Tim Curtis noticed the smell of natural gas in their Lawrence apartment.

“And then we actually felt the explosion from the house, I believe, on Jefferson Street,” Grondin said.

About 80 homes in the three neighboring communities — Lawrence, Andover and North Andover — were on fire. Several houses blew up, including one explosion that killed a teenager.

“It was scary,” Curtis said.

Thousands of homes were evacuated, including theirs, and they stayed with family for a few days. But they’re back home now with their one-and-a-half-year-old, Ricky, who toddles around holding a rubber ducky. A small space heater sits in the middle of the floor. Ricky keeps toddling towards it.

“That's hot,” his mother warns. “Don't touch it.”

Grondin worked at a pizza shop down the street, but she is out of work — the shop has been closed since the natural gas was shut off, more than a month ago. And they don’t have any heat at home.

“It's been cold in here,” Grondin said. “I mean, we're in a ... basement apartment, so naturally the concrete is going to be cold, just with that alone.”

Since the incident, the utility, Columbia Gas, has been working to replace 44 miles of old pipeline. The company is also busy replacing thousands of damaged furnaces, water heaters and home appliances, and say it's on track to meet its target of restoring all service by November 19.

Curtis doesn’t trust that will happen, and says he just doesn’t know when they’ll have heat.

“No idea,” he said. “I don’t even know how this happened.”

That’s under investigation. A preliminary report faulted Columbia Gas for not taking proper safety measures to prevent the disaster.

As it gets colder, the utility is putting people up in temporary housing, and Grondin says she’s been trying to get one of those spots. The company told her the family could have a hotel room in Nashua, New Hampshire, about 20 miles away.

“And I said, 'Well, unfortunately, that's not going to work,'” she said. “We don't have a vehicle.” Grondin's stepfather, who also lives with them, is getting cancer treatment nearby and can’t be that far away.

Andrew Maylor, North Andover's town manager, says a lot of people would rather stay home.

“But I think as it becomes multiple days, over the next week or so we're steadily in the 30s in the evening. That's not something that can be sustained in a safe way,” he said. Especially since there’s a real concern that some space heaters might start fires.

As of Monday morning, Columbia Gas reported that more than 37 miles of main line pipe had been replaced — more than 83 percent of its target — as well as more than half of the service lines that need to be replaced. Six-hundred-and-ninety residential and business meters have been re-lit, with more than 1,200 to go. The company is putting up more than 1,900 families in temporary housing, including hotel rooms and RVs. And it's received more than 21,000 customer claims for everything from damaged appliances to lost wages and report having paid out $23.7 million so far.

“We understand the frustration. We understand the inconvenience, but we are doing everything we possibly can to reduce the inconvenience to our customers and to give them the ability to stay warm,” said Columbia Gas spokesman Dean Lieberman.

Ana Javier works with the social services agency Lawrence Methuen Community Coalition, and says she’s seen a lot of stressed out people.

“I see a lot of people that are struggling with anxiety, depression. And I really feel at this point a lot of our people are going to need a lot of counseling in our area,” said Javier.

For Grondin, the main source of stress right now is getting her family into someplace warmer.

“I know we don't really have any room to be picky because there's so many thousands of people that were affected,” she said. “But hopefully I can get through to somebody today and figure it out.”

With the nights getting colder, she’s hoping it happens quickly.