Hi James
I have not used hot so would not know for sure.
however yesterday I was cleaning a complex of several blocks of flats and got talking to a windy who was doing a similar neighbouring block.
He had hot water, uses it all year , he pointed out quite rightly that we clean our dishes with hot water and I'm sure it would remove birds mess stains a lot easier.
I looked at a couple of the windows he cleaned and compared to mine, end result same.
Not to say it isn't of use but on the whole imo it isn't needed.
The biggest difference I noticed though was I was using a 25ft ( supermax 40 with sections removed ) whilst he was using an extreme, speed wise we were about the same but he looked like he was having an easier time and less tired, it was only one block though and I had six !
Point being if I had money to invest and wanted to see a marked improvement in my working day and productivity it would not be spent on a hot water system.
Ok Daz, I know, I know, you've been saying it for months