First They Came For the Window Washers: "Window Cleaning Robots Making Their Way To Skyscraper Happy UAE"

The technology was originally developed to clean solar photovoltaic panels, a high value use when dust can cut electrical production 10 to 50%. The fact that they make economic sense in this application has to be troubling for the window washers guild.

As of 2012 Serbot is a small part of material handling/heavy lift specialist Heppenstall Technology AG.
 
From Singularity Hub:

Source: Serbot

These robotic window washers are not afraid of heights, high winds, or hard-to-reach places. Gekko Façade and its sister, solar panel cleaning robot Gekko Solar, imitate their lizard namesake by clinging to high places that would unnerve the most intrepid of humans. Which is why the humans could very soon be out of the job.

Gekko Façade is better than window washers, hanging precariously outside office windows on a swinging platform. Not only for the sheer glass it can cover – 576 square meters per hour – but its suction cup feet allow it to stay safely attached while it cleans with a rotating brush, even on curved surfaces. It’s sufficiently nimble to get to all those hard to reach places like a Spiderman Roomba. Of course, it doesn’t always perform death-defying cleaning stunts. Gekko Façade can clean flat surfaces as well....MUCH MORE