The average window will take the average window cleaner 90 seconds to clean.
This is a window about 5ft by 3ft 6"
One narrow opening light, 1 pane underneath that and 1 to the one side of both of those.
That is of course a time for trad and includes the sill but not the frames, but does allow for detailing.
How many window in an hour is a bit like how long is a piece of string isn't it?
It all depends on how big the windows are, whether they are georgian or leaded and so on.
I charge a £1.00 a window and I'm not prepared to say how many I do in an hour
Ian