It can only fly in wind/gusts upto 15mph! Says it can do 180 bar yet the drone can only take ip45 = low pressure jets, so if a hose fractures and sprays the drone it's not going to survive.
I like the idea but I don't think it's going to work. I very much doubt just spraying on some solution and then I assume rinsing it off will actually clean the windows or cladding.
Just spotted that they are using a quadcopter - only 4 motors and props. They have no redundancy should a motor/prop or esc fail!! Surely that can't be approved for flying in public areas where they have no control over the public? That's just nuts. It must weigh about 15kg or more especially when you consider hose, fluid, 3 hour battery (they say 8 batteries gives 24hrs operation), maybe battery in rotation they can go indefinitely. They do look to be a franchise and have operations in many countries so either franchisees are very gullible or there is more to it.