Think we will have to look at a hot system to add to this. Capital power in Edinburgh fit them which is nearbyTechnically it might freeze faster but @dazmond is right we melted ice off window frames and glass the last few days without it re freezing , I think this is due to the fact you continue to apply the hot water where as cold is slow running down the window and it sticks to the already frosty surface , we were using 65 degree water in -1 degree this morning which I accept isn’t that cold but in 2010 it was -6 and we worked in that without anything freezing on the glass , when I was cold wfp I had no end of problems with it freezing on the glass never had that happen since going hot . Ime not criticising what you are saying just sharing my personal experiences with this .