LOUISVILLE, Ky. (WDRB) -- Wednesday was the coldest day in the Louisville Metro area in nearly two years. Temperatures dipped as low as eight degrees, and the wind chill was below zero.

Dr. Joshua Honaker with the Norton Medial Group said those temperatures could lead to an increase in illnesses.

“The biggest things you might worry about are hypothermia and frost bite in elderly and infants," Honaker said. "You worry about them, because they can be sicker with their chronic diseases.”

If you have to be outside, experts say bundle up to limit exposure to the cold. Inside your home, where it's hopefully nice and warm, HVAC specialists like Matthew Koch are working hard to keep it that way.

He said his work load doubles when it gets this cold.

“Guys could be running 12 or 14 hours,” Koch said.

Koch is cleaning furnaces, keeping them from breaking down and fixing them when they do.

“Most of the time when we go out, it could have been something that was prevented,” Koch said. “The furnace could maybe run 20 times a day on a good day, and then on a day like today, it could run 50. You never know. It just depends on the house.”

He said there are three serious reasons to have annual maintenance on a furnace: safety, to cut costs and to keep you comfortable.

“If it ever cracks, you're burning a fuel, you can create carbon monoxide with combustion, and then those cracks let it seep through the cracks and into the duct work, and then it gets blown through your house,” Koch said. "[You want to] keep the equipment working so you're comfortable, keeping it clean so it works efficiently so your bills are comfortable, so you're not paying too much and of course, it's your house. You're living in it. Why be uncomfortable in the place you're staying?”

Koch offered a piece of advice: pick the same day every year, for instance around a birthday, and make a maintenance appointment for some time around that day.

“If you neglect your car, it's going to break down," he said. "If you neglect your heating and air equipment, it's also going to break down.”

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