What is Thermal Conductivity

Thermal conductivity is basically the property of a material that allows the flow of heat through the material. It is also known as the coefficient of conductivity, because it is given as a number that can be used in equations. The thermal conductivity of any particular material, because it indicates how well it allows heat to flow, is therefore also a good indicator of how well the material insulates, or blocks the flow of heat.

The Facts

Thermal conductivity is given as a number that is represented by the letter "k." For materials that allow heat to flow almost freely through the material, such as copper, the value of k is more than 300. For insulation materials that are used in the walls of homes, the k value is less than 1.

Considerations

Gases have low k values, or thermal conductivity values, and are therefore considered good insulators. Many homes now have double-pane windows with a layer of air between them. Because air is a gas, it provides a good insulating layer for the window. In general, layers of materials that have air between them prove to be effective for insulation purposes.

Warning

Asbestos at one time was considered to be a good insulating material because of its thermal conductivity value and the air layers in the material. However, asbestos was discovered to be carcinogenic. Pulling apart asbestos insulation in order to install better insulating materials should be done only by professionals who take the utmost precautions with their work.

Benefits

The benefits of insulating material with low thermal conductivity values can help prevent the loss of heat from homes during cold winter months. Many newly built homes have "green" elements associated with them. These elements usually involve increased insulation and better insulation materials that have lower thermal conductivity values. Although they might cost more initially, the savings in home heating costs will eventually make up for the difference.

Potential

New material processes continue to improve home insulation that find ways to incorporate low thermal conductivity values. For example, some double-pane windows now come with argon in the enclosed area between the panes. This is because argon has a lower thermal conductivity value than air. New advancements in technology can continue to finds ways to improve home insulation.