A hydronic panel and system for heating and/or cooling a room is disclosed. The hydronic panel includes a plurality of contiguous channels. A first chamber is located at a first end, preferably the upper end, of the panel and includes an inlet and communicates with a first subset of the channels. A second chamber is located at an opposite end of the panel and communicates with the first subset and also with a second subset of the channels. A third chamber is located at the first end of the panel, the third chamber communicates with the second subset of the channels and includes an outlet. In this configuration, heated or cooled water flows from the inlet into the first chamber, through the first subset of the channels, to the second chamber, through the second subset of the channels, into the third chamber and out the outlet. Consequently, the heated or cooled water can heat or cool the space. In addition to at least one hydronic panel, the system includes a source of heated and/or cooled water under sufficient pressure to cause the water to flow through the panel. The system also includes a controller to control one or both of the temperature of the water and the flow rate of the water through the panel.