An integrated fixture for transferring heat from a higher-temperature loop to a lower-temperature loop (e.g., in radiant heating, from a heating unit loop to a radiant loop). The fixture provides a heat exchanger for transferring heat from the higher-temperature loop to the lower-temperature loop. The fixture also includes a casting, in which are formed higher-temperature supply and return ports, lower-temperature supply and return ports, a higher-temperature pump volute, and a lower-temperature pump volute. Liquid from the higher-temperature loop enters the integrated fixture through the higher-temperature supply port, passes through one side of the heat exchanger, transferring heat to liquid circulating through the other side of the heat exchanger in the lower-temperature loop, and leaves the integrated fixture through the higher-temperature return port. Liquid circulating in the lower-temperature loop enters the integrated fixture through the lower-temperature return port, receives the heat from the higher temperature liquid, and leaves the integrated fixture through the lower-temperature supply port. The invention simplifies installation by integrating into one integrated fixture all four ports and both the heating unit loop pump and lower-temperature loop pump.