Abstract: The present invention relates to an in-floor radiant heating system having a tube that is received into low profile panels. Channels are formed in the top of the panels. The channels can have a neck shaped top section and a circular shaped bottom section. The bottom section has a diameter that is larger than the width of the top section. The diameter of the tubing is smaller than the diameter of the bottom section to ensure a snug fit. Flares can be located between the ends of the channels and the sides of the panel to allow the tube to bend and fit between adjacent panels that are offset up to a determined amount. A transition piece can be used to interface between a room with the in-floor system and one without. An installer can see the top of the tubing during the installation process.