I grew up in the Dandenong ranges (so freezing ), and our house had wall to wall slab heating. Devine is the right word for it! We never knew it was cold until we stepped out the door. But yes, it is very costly to run, and from memory could take awhile to heat the house up if it had been off for awhile (we had an open fire too, so that always got us over that hurdle). But I don't know, maybe the systems have been improved so that is no longer an issue.