Cable heating systems heat surfaces in the room, not the air itself. These heating systems are designed so each room is heated individually.

With a cable heating unit, cable wiring is looped diagonally throughout the ceiling and enclosed in the plaster. Each room is controlled by a thermostat which tells the system when to turn on and off.

Heat radiates from the wires in the ceiling down to furniture and other surfaces in the room, warming them. The heat is then conducted from those surfaces to the adjacent air. The process is similar to how the sun heats: the sun radiates heat down to a rock, and the rock then radiates that heat to the air around it.

Tips for operating and maintaining a cable heating system

• Turn down the thermostat in rooms that aren't being used and close the door to that room.

• Temperature settings should be about the same in adjoining rooms where there is no door between the rooms.

• The lowest thermostat setting for cable heat is about 55° F. To turn off the entire system, you should switch the circuit breaker to the "off" position.

• When adjusting the thermostat, set it back a few degrees at a time. Large setbacks aren't recommended because it takes longer for radiant heat to rise to desired temperatures.

• Don't set the thermostat above the desired temperature setting. Doing so won't speed up the heating process.

• Insulate your attic. A poorly insulated attic will magnify heat loss through the ceiling, because you're initially heating the surface of the ceiling.

• Use extreme care when installing anything in the ceiling. A break in a wire will cause heat for the whole room to fail and may expose a person to electrical shock.