Changing a lightbulb in your own place is one thing. Try doing it 1,500 feet in the sky while standing on the roof of the tallest building in North America with only your own balance and wits keeping you on solid ground.

It's all in a day's work for Willis Tower electricians John Barker and Mike Hlavacek.

"It never gets boring," Hlavacek said with the smile of a man who has clearly been asked about his day job before. "It's the greatest view, the most beautiful city in the world I think. On a clear day like this, you can see four states without a problem."

"We consider this the 110th floor," Barker said, though you won't find a "110" on any Willis Tower elevator available to the public. "You cannot get any taller in North America."

RedEye joined Hlavacek on the roof last week as he performed some maintenance, and he gave us the lowdown on his job. All told, there are 20 light fixtures on the roof of the Willis Tower, each about 20-inches around, powered by a 1,500-watt bulb that lasts anywhere from six months to a year and is visible for miles around. 

As for why the bulbs last so long without burning out, Hlavacek said all the credit for that is for the birds. Literally.

"The lights go on at sunset and they're usually only on until around 11, 11:30 at night because the building is with the other buildings downtown where we do it for the bird migration where we don't have the lights on so they don't slam into the building," he said.

So what's it like to change a light bulb on the roof of the Willis Tower? Hlavacek said it's really not all that different from changing a lightbulb around your house, so long as you're taking the proper safety precautions, that is.

"You just gotta be careful because you wanna make sure you get gloves on," he said. "You don't want the bulb to explode in your hand. A lot of times, some of the bulbs you're replacing are broken."

Hlavacek said the biggest difference is the person standing over him.

"One is my wife telling me to do it at home, the other one is John Barker, my boss, telling me to do it here," he said.

The lights atop the 350-foot high antenna are another story.

Barker said those lights last around five years. The Willis Tower utilizes an outside contractor to change those bulbs, so neither of the building's full-time electricians has been up quite that high.

Naturally, there's a higher degree of difficulty when it comes to that particular task.

"You can go up through the inside of the antenna to the top to replace any strobe," he said. "As you go up through the ladder system, I'm certain they're tied up to a safety harness. We've been up just a short distance because of the microwaves and those levels, we don't want to go too high."

Adding color to the roof's lights is also a fairly simple task requiring a pair of nimble fingers and a giant plastic disc.

Barker and Hlavacek will walk around to each light on the roof, unscrew the bolts around the outside of it and set the colored acrylic disc into place. All told, the entire process takes less than five minutes.

Barker said the men find themselves up on the top of the city changing the discs as often as three times a week.

"Depending on events going around the city and all over the world, it's hit or miss," he said.

This week, the lights are teal in honor of Ovarian Cancer Awareness.

Prior to the late 1990s, Willis Tower electricians actually used gels instead of acrylic discs to cover the lights on the roof to give them some color. Heat generated by the lamps would often melt the gels, prompting building staff to look for an alternative that could generate the same effect without requiring any cleanup.

Inspiration struck Hlavacek while watching a History Channel documentary on how electricians at the Empire State Building handle similar maintenance tasks.

"When I saw them doing plastic lenses on there, that Monday morning, we called the electrician at the Empire State Building who was nice enough to send us photos and a portion of the lens so then we were able to go from there and do what they were doing," he said.

There are plans to eventually get rid of the current lighting system and the plastic inserts altogether.

Hlavacek said they've been looking into switching to a more environmentally-friendly LED lighting system, which would allow them to automatically change the colors via a computer control system.

There's just one problem--LED lights don't do very well in the Chicago winters.

"The problem is LEDs don't produce any heat," he said. "We had the lights on for 24 hours and the snow never melted off the LEDs. Nobody's come up with a real good idea of how to shoot the LEDs up."

It's impossible not to be awestruck when you open the door and walk out into the open air on the roof. There's no fence surrounding it, meaning it's entirely possible for you to walk right up to the chest-high ledge and look down although, having done that, it's not recommended.

So surely the men must get at least a little nervous when they're up there doing their jobs. After all, you're high enough to where the Hancock Center and Trump Tower look almost like the skyscraper equivalent of a nerdy kid brother.

"I don't, no," Barker said. "Nothing to be nervous about. Everything is safe."

As they're showing us around the roof, one thing becomes noticeable for its absence--the wind.

My photographers and I are all walking around completely unharnessed. In the 90 minutes we're up there, the view takes our breath away as does a climb up a rickety ladder to the area that Barker and Hlavacek affectionately refer to as "The Penthouse," where the TV and radio transmission equipment is located in between the two antenna. Never once does a gust of wind stronger than a breeze threaten to sweep us off our feet and onto the street below.

Barker said that's a fairly common thing--although Mother Nature does occasionally through them a curveball.

"There's good days and bad days," Barker said. "We've come up here where you can have gusting winds 30, 40, 50 mph, but then you have a peaceful morning like this. We do have our wind speed direction meter. That gets a little hairy at times because you're up on the penthouse roof. On a good blustery day, you're getting blown around a little bit."

Matt Lindner is a RedEye special contributor.

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