Traditional cast iron radiators are no longer common in new construction, replaced mostly with forced hot water baseboard style radiators. They consist of copper pipes which have aluminum fins to increase their surface area. These conduction boiler systems use conduction to transfer heat from the water into the metal radiators or convectors.
The radiators are designed to heat the air in the room using convection to transfer heat from the radiators to the surrounding air. They do this by drawing cool air in at the bottom, warming the air as it passes over the radiator fins, and discharging the heated air at the top. This sets up convective loops of air movement within a room. If the register is blocked either from above or below, this air movement is prevented, and the heater will not work. Baseboard heating systems are sometimes fitted with moveable covers to allow the resident to fine-tune heating by room, much like air registers in a central air system.
Sterling produces several different residential baseboard brands, and is one of the largest baseboard manufacturers in the country. Sterling brands include Kom-Pak, Suntemp, Petite, Heatrim and DesignLine.
All Sterling baseboard elements are mechanically bonded. This is achieved by expanding the copper tube so that there is a tight bond between the copper tube and the collar of the aluminum fins. This process is unique to Sterling.