DALLAS – At its worst, this heat can be dangerous. At its best, it's uncomfortable.

"Nobody wants to sleep in the heat. It's hard to operate in, especially with a baby, we need her to stay comfortable," said Stephanie, a stay-at-home mom in North Dallas who didn't want to give her last name.

Stephanie is on the uncomfortable side. The problem? Her thermostat is set to the low 70s, but the reality is, it's much hotter.

"It's a lot to deal with, especially when we've had a forecast like we've had this week," Stephanie said.

It's one of many stops in what will likely be a 12-hour day for HVAC Service Technician Christopher Shriver of Milestone Electric.

"It's not too bad when the weather is cool, but then when the weather starts to heat up and there is extra heat load on the house, the system has to continually run. That's when the weaknesses start to show," Shriver said.

That's what happened to Stephanie's air conditioning unit as record temperatures push the limits of systems across North Texas.

"This is the end of May, and it's already started. We're geared up, and we're ready for it," Shriver said.

It's not just about comfort. Heat can turn dangerous very quickly. In fact, this heat wave that has already placed as many as 20 people in the hospital and left one person in critical condition, according to MedStar.

It makes getting an air conditioning inspection that much more critical.

"It started to feel just not as comfortable as we typically like it, and we just wanted to be sure that everything is in tip-top shape before we head into the heat of the summer," Stephanie said.

Shriver and his crew head to the attic. Temperatures there can top 120 degrees – it's all part of the job.

"I hope I have a really cool house by the end of the day, and that we can get through this super hot week coming up," Stephanie said.

By the time her house cools off, these guys will be off to the next call. Hard work that will continue as long as the temperatures cooperate.