Well i have to say, on trying it today i still cant see the difference in cleaning power with hot water vs cold. Well actually snail trails were much easier to clean off.. but thats it i think.
However, it was nice having hot water to work with this morning qt 8am at 4 degrees c, it certainly made it easier to handle the hoses.
One thing i did notice was how much heat is lost through the hose. Had a large house to do this afternoon which requires full extension of 100 meter hose, the boiler was running at 60 degrees c just to get warm water out at 20.
With the hose wound up, heat retention goes up like 70 percent. So i think i need to look at thicker hoses that won't loose the heat.
But like i said, i just want the heater so i cabln continue with water flow at minus temperatures. Not too bothered if its any better for cleaning with, just minimizing winter down time.