My opinion is hot water is nice, it’s easier to work with. But it makes no more money than cold.
There is no way I clean more windows with hot water than cold, it’s more of a luxury than a money maker.
It’s the exact same thing with my electric hose reel, it makes me no more money, i still do the same rounds as I did without one, it’s just easier, and that really is the only benefit, easier work.