- Heat transfer, the collective term for all the heat that is generated and lost in your home, can actually occur by way of conduction, convection and radiation. If the air inside one room that's heated by a furnace travels through walls to another room, for instance, the heat in the first room is being lost due to radiation. But when new heat is supplemented into that same room to compensate for losses due to radiation, the heat makes its way into the room through convection.
- Since convection refers to heat transfer due to the movement of air or water molecules through a space, the majority of thermal conductivity produced by a furnace uses convection to distribute heat. When a furnace is kicked on by a thermostat, it heats air inside its combustion chamber and distributes that air throughout the home via a system of ductwork. As the heated air is distributed throughout the home, the air temperature inside the home is raised and the thermostat deactivates the furnace.
- As noted, heat transfer in the home occurs as a result of radiation, convection and conduction together. But the furnace itself tends not to use these heat transfer methods to distribute heat. A space heater distributes heat through radiation, since radiation refers to heat transfer via infrared rays. Conduction forces heat loss through physical contact, such as when a person touches a hot surface and their hand turns hot as a result.
- The fact that furnaces use convection to account for heat loss in the home due to convection, conduction and radiation underscores the importance of using multiple heat sources to heat your home. Even a high-efficiency furnace can account only for so much home heat loss on its own; using fireplaces, space heaters, blankets, good insulation and a well-sealed home can assist the furnace in accounting for heat loss throughout the entire home.
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