I use hot everyday, and have done for the last 8 years or so.
As ive said on this forum numerous times, imo using hot during the winter is just for ease of use, shpple hoses and not freezing jets.
Using hot for the rest of the year, aids cleaning, more pollen spots, spiders poo, snail trails etc.
I dont have the water boiling hot ( unless im cleaning conny roofs/fascias etc, just nice and warm.
It costs me around 1% of my weekly takings, this is using autogas from the garage at 59p per litre.