Radiators are the most common source of heat transfer, but radiant loops are gaining popularity.
Installation and materials costs have made aluminum finned copper tubing the most effective style. Baseboard, whether copper or cast iron, is run in a continuous loop from room to room, but the larger cast standing radiators work better as a supply and return loop or as a monoflo loop. Using a fitting called a monoflo T, One pipe can feed the entire loop of standing radiators. Unique but simple, the monoflo T uses an orifice placed to one side of the t arm to restrict the flow of water through it. Down side of the flow it forces water into the arm.