You must have a tiny burner if thats all the diesel you burned on a house.But anyway its a good marketing strategy and if it works thats great.If i washed a house with no heat and you did one with heat assuming we had the same chemicals after we got done i bet there wouldnt be a difference at all.However if we did two road tractors and it was below 50 degrees one used hot and one used cold there would be a visable difference if there was any road film or oil on the trucks.Thats a neat picture i like that.I gonna make me on and put it in my book.
I bet heat is the way to go in the winter for black streaks on gutters also, herd some spike their f13 with purple power???