Insulation and Ventilation Tips

Many new products have been developed in the insulation industry over the past few years; before discussing types of insulation, let’s take a look at some specific terms used in the heating and cooling industry.

Conduction, convection and radiation are the three most important terms to consider.

Here are the definitions per Wikipedia:

· Heat conduction, also called diffusion, is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems. When an object is at a different temperature from another body or its surroundings, heat flows so that the body and the surroundings reach the same temperature at thermal equilibrium. Conduction happens in both fluids and solids.

· Heat convection only occurs in fluids. It occurs when bulk flow of a fluid (gas or liquid) carries heat along with the flow of matter in the fluid. The flow of fluid may be forced by external processes, or sometimes (in gravitational fields) by buoyancy forces caused when thermal energy expands the fluid (for example in a fire plume), thus influencing its own transfer. The latter process is sometimes called "natural convection". All convective processes also move heat partly by diffusion, as well.

· The final major form of heat transfer is by radiation, which occurs in any transparent medium (solid or fluid) but may also even occur across vacuum (as when the Sun heats the Earth). Heat transfer by thermal radiation is the transfer of energy by transmission of electromagnetic radiation described by black body theory. (HUH!!?!)

To simplify these definitions in layman’s terms:

· Conduction is the transfer of energy through a surface, such as a window. You can put your hand near a window on a cold day and feel conduction.

· Convection is the transfer of energy through the air such as a breeze blowing through an open window or the ‘breeze’ that blows through leaky doors, windows, walls, ceilings, etc.

· Radiation is not considered as important in insulation applications but it is the energy you feel on your skin when standing in the sun.

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