About useless to heat the floor in most of Georgia. The temp swings are usually so great that it might be 20 one day, and 70 two days later. It takes days to get a slab up to temp and you would have to react well ahead of the cold to start the boiler and heat up the water, and then in a day or so it would be past.
This year is an exception, staying cold all day, for days on end. Still, it gets to 50 a couple of days a week even with this crazy cold we are having.
Many years ago, Georgia Power had a electrically heated slab in their truck shop in Columbus. Don't know if they still do. Guys said it would almost get too hot to stand on. Of course the power was free.
I've been keeping the shop at 40° in this cold, but generally it won't ever go below freezing, due to the heat in the slab from the warm days, as mygarageone suggested.
In the Atlanta area it was about 50° Sunday afternoon, but down to mid 20's the next morning, and back up to 50 or so on Monday, then down to 20 or below mon nite and hasn't got above freezing today (tuesday).
Charles
