The window-cleaning division of Service Employees International Union Local 32BJ, one of the largest unions, counts 800 members.

WSJ: Window-Washing Robots Rise; Humans Balk

So, obviously, it was with no small amount of skepticism that I listened to Mr. Savadian as he touted his window-cleaning robot.

WSJ: Urban Gardner: The Joy of Clear Glass

Ecovac manufactures the Winbot, a window-cleaning robot.

WSJ: Urban Gardner: The Joy of Clear Glass

Gift certificate for a day of yard work, house cleaning, window washing, or car washing.

FORBES: Holiday Shopping Savings Tips

So, for every window, you're effectively cleaning two windows.

WSJ: Urban Gardner: The Joy of Clear Glass