I can understand a high volume of terraced houses an hour, but only if they are tiny and the backs are all straight forward to get at.
Many terraced houses only have 2 or 3 windows on the front and a similar amount on the back.
So if you do a string on then on the fronts first, and if you don't have to walk up and down front gardens to get at them, just walk down the pavement going from one to the other, then ok, you will really be able to blast through them...but the backs also have to be fairly straightforward too.
An average sized window, with 3 panes of glass will take you once experienced, 90 seconds.
Wash.
Squeegee.
Detail.
Wipe sill.
I'm talking trad there of course.
WFP will do the same job, on repeat cleans in 30 seconds.
If you are treating it as a competition then trad will be quicker, but you cannot operate constantly at race speed, not if you intend to do a decent job.
30 semi's a day?
An average semi will have 12 windows, done trad you WON'T knock a house of that size out in ten minutes...dream on.
You have to time it at a minimum from walking up the front path or drive, to walking back down it once done, and allow for either collecting or invoicing too.
You cannot expect to have a round so massively compact that you are going to have house after house virtually next door to one another, that take years to achieve for gods sake!
And even then, not many will have day after constant day like that.
The majority of window cleaners are at work by roughly 8.30am and they are home with their feet up by about 4pm.
Most are doing well if they work 7 hours a day.
Take out tea breaks, lunch breaks, toilet stops, customers who chat, people who call you on your mobile and so on, and you are very lucky if you are working, ACTUALLY working for much more than 5 and a half hours on an average day.
And even if you are already an experienced window cleaner, having worked a year or two for someone else, starting out it will take you a couple of years to have built up enough work to be earning a halfway decent income, and a great many more years to have built it up and honed your round to give you a top income.
Time I wasn't here...I start at 7am!
Ian