We are considering a radiant floor for a Central Texas Sunday house (old German design approx 33x 23 with 14 foot open to gable roof on the rock side and 9'-7' ceiling height on shed roof side. It is double rock walled on three sides and wood on the shed roof part, with an existing concrete subfloor 5 "beneath the final grade which as been poured higher on the other half of the building. We are adding a bedroom continuing the gable roof so the concrete has not been poured for that part of it. I know this may sound confusing..but maybe not to some of you out there. I know there is a pex type tubing and am wondering about expense of operating once installed. Isn't that cold in Texas much of the year..except maybe THIS one! Hey..thanx guys!