In May, I set foot on the highest residential terrace in the world, the outdoor space of the penthouse at the Central Park Tower in New York City. A part of the so-called Billionaires’ Row, Central Park Tower is among the tallest buildings in the world, and its exterior is primarily glass. As I sipped a glass of Dom Pérignon standing 1,416 feet above the ground, alfresco, I looked back at the building and wondered: How do you clean these windows?

Someone has to wash the windows and polish the facade. For the super tall skyscrapers of the world, that someone is sometimes a robot.

Two companies, Verobotics and Skyline Robotics, are looking at making the estimated $40 billion window-washing industry safer and more efficient by using AI-driven robots to mimic the work of human window washers while also scanning the surface for necessary maintenance information for other facade-focused issues. By utilizing AI along with hardware, both companies are betting the vertical living of our urban environments is going to need a lot of TLC.

“The exterior of a building acts as its protective skin, a vital component that affects not only the well-being of its occupants but also the building’s energy efficiency,” said Ido Genosar, cofounder and chief executive officer of Verobotics. “Surprisingly, building exterior upkeep has seen little innovation in the past century, despite becoming more expensive. Our goal is to proactively address issues in how we maintain and safeguard the ‘skin’ of our cities’ rising skyscrapers.”

Genosar’s robot, dubbed Ibex after the wild goat known for its impressive climbing skills, looks similar to iRobot’s automated home vacuum Roomba but functions entirely differently. To start, Ibex suctions itself to the sides of buildings using two legs, five cameras, and 15 sensors so it can autonomously navigate a facade. A special payload attached to the robot is deployed for cleaning, using custom-built brushes. It’s all controlled by one operator, who can monitor up to four robots on a single building simultaneously.

While the robot cleans, it uses the raw data from the multiple sensors to build a real-time, 3D map of the building, including the state of the infrastructure. Genosar explained that when used regularly over the course of a year, the model updates with exterior changes and can highlight potential problems while they are small and manageable versus causing a bigger problem down the road.

“Using AI to gather methodological and consistent data on the building-facade health enables building owners to dramatically improve their proactive maintenance work and plan ahead for needed repairs based on severity,” Genosar said. “That reduces costs associated with maintaining a building’s facade.”

Genosar explained that he and his cofounder, Itay Levitan, who serves as chief technology officer, developed the robotic system after Genosar saw the limitations of current building maintenance options through his family’s construction business. Old solutions were bulky, heavy, and expensive, and beyond that, weren’t prepared for the changing climate and the resulting shift in weather patterns for many urban areas. Nor were they prepared for the heights of the world’s newest builds: 60% of the tallest towers were completed in the past 13 years.

The increased frequency of extreme weather events, such as typhoons and heavy rainstorms, has an effect on buildings, Genosar said. It’s more dangerous for window washers to clean amid these conditions—in terms of wind, heat, and sun—and it’s more likely to affect the overall structures. Much of his work, he said, is focused on Hong Kong, Singapore, Seoul, and Tokyo, well-known for their clusters of skyscrapers.

In New York and London, Skyline Robotics is working to rethink facade maintenance for the U.S. and Europe. The company just launched in London in October, but you can already see its robots on Manhattan towers such as 10 Hudson Yards and 7 World Trade Center.

Skyline’s robot, called Ozmo, has mechanical arms structured to mimic human movements and can clean windows three times as fast. The Ozmo also reduces on-site labor costs by 75%, according to Ross Blum, Skyline’s president and chief operating officer.

More important, said Blum, Skyline robots are helping to solve the labor shortage problem in the window-washing industry. It’s a risky job to hang hundreds of feet in the air and wipe down glass, so it’s not surprising that only 9% of window washers are between 20 and 30 years old. The vast majority are over 40 years old and likely to retire sooner than later.

“They have to hang 1,000-plus feet in the air, doing manual labor, and it can be 40 Fahrenheit or 110 degrees outside, but no matter what, they have to get the job done,” Blum said. “The reality is that the work isn’t incredible, and the next generation isn’t showing up.”

Blum explained that robotics offer younger workers a different incentive: to learn about new technologies and gain a transferable skill set. With Skyline, Blum sees window cleaners and robots working in tandem. “Our technology will never be used on 100% of buildings that exist; there is always room for a human workforce.”

Ozmo features a six-axis robotic arm with the same joints as a human arm. It’s placed on a table that’s secured to scaffolds suspended by cranes or davit systems from the roof. From far away, you may even think there are two window washers overhead. Instead, the human controllers are on firm footing in the building, where they can monitor from above.

Ozmo, however, makes most of its own decisions. It calculates 250 times per second to decide on such variables as how much pressure for cleaning, where to apply the brush, and when to move the scaffolding to the next level—all this to determine the most efficient cleaning path. It also takes stock of the building’s facade conditions and reports back data on potential issues that need to be addressed.

Blum explained that the cost savings and added data collected by robots is critical to the health of the world’s tallest buildings. When a building’s owner can implement cleaning, polishing, and inspections more often, they can best map out construction projects and repairs. Today, most facade checks occur on a 10- to 15-year cycle, but Blum believes most real estate owners would like a shorter time frame.

“Roughly 10% to 20% of a building’s budget is allocated to the facade of the structure; for a $1 billion building, that’s $200 million,” Blum said. “That’s the look of your asset. You want that checked with greater regularity.”

New York City, for instance, has more than 7,000 high-rise buildings, with more than 100 soaring higher than 650 feet and 16 buildings taller than 1,000 feet. From my window, I can crane my neck to see the top of a new residential tower that reaches almost 850 feet. It certainly will need cleaning from time to time.

“If someone is paying for space on the 80th floor of a building, they’re paying for the views from that vantage point,” Blum said. “They deserve clean windows.”