Unfortunately the best time to put radiant heat in my first floor slab has long since passed… however, I’m wondering how feasible it might be to add now, before I tile the slab. About 800′ feet to be tiled altogether.
Has anyone had a successful experience with adding radiant heat on top of a slab on grade? One option that seems attractive is low-profile electric mesh (eg http://www.wattsradiant.com/pdf/heatweave) because you can get away with a thin bed tile installation, which in turn saves a lot of work trimming doors & casings, and keeping the stair height from getting out of whack. Those are serious considerations given the size of the job. On the downside, the max square footage covered by an electric system is small so I’d probably end up just picking a few spots to heat.
Are these electric systems any good?
From what I’ve seen of it, the slab doesn’t have cracks in it, and it’s been around for awhile (12 years or so), so I’m not overly concerned with isolating the tile from the slab. On the other hand, I haven’t measured how flat it is (it being carpeted at the moment), and I’m considering a butted-tile travertine installation, which would demand a very flat slab. In that case it may be worth the expense of a thick bed job. (Or just forget trying to butt the tiles.)
thanks for any and all comments.
Replies
While you can use any of the electric cable tile warming products over your slab, none will provide the heat that hot water tubing within the slab can provide. Your electric cabling just won't be effective in heating up the thermal mass of the concrete.
All the electric tile warming product people will say the same thing, and that is this: our product heats tile for comfort at the feet, but it is not to be considered a radiant heat method.
Thus said, consider this. If you set your tile thermostat at the high setting, so it stays on for long periods, it will probably get some heat down into the slab, and then the two (warm slab and hot wires) will combine to provide you with some real temperature change up higher.
If your electric rates are low, this might be an effective way to heat. If not, you may need a second or third job to support your radiant floor habit.
You should do, or have done, a heat load analysis for the space. I think that the output of the electric tile heaters would not be enough to heat the space. An analysis would give you the facts.
yeah, the more i think about it, the more i realize i'm SOL on floor heat. From the little I've read and heard from others, I tend to agree that electric elements won't scale to an installation of this size and they'll just provide a band-aid solution. A mortar bed's too expensive for me and that doesn't leave many options. thinset, tile, and warm socks it is then!
thanks to both of you.