I use one, but only occasionally on really trashed carpets, pubs restaurants, end of tenancy jobs etc,
i find it works really well, even from cold.
Why does putting hot or warm water in your tank defeat the point ?? you got to put something in wet,
might as well be hot/warm water.
I keep it 25-50' from wand, adjustable, so can have it warm or very hot.
regards, Andrew