Abstract: The invention is directed to a method and apparatus that utilizes heated fluid circulated through heat emitting tubing held within heat emitting plates that transfer heat from the tubing to the sub-floor of an occupied space for purposes of heating that space. The configuration and placement of the heat emitting plates is such that heat is transferred by means of conduction, convection and radiation while avoiding potential puncture from nails or other penetrations of the sub-floor from above the sub-floor. A manifold configuration allows for fluid distribution to the heat emitting tubing in joist spaces.