Insulation is used in a home to control how heat is transferred from the interior to the exterior:

• Heat flows from hot to cold
• Heat flows by conduction, convection and radiation
• Heat flow can never be stopped, it can only be slowed down
• Insulation resists heat flow and is rated for it's R value (RSI)
• R-value tells us how well a particular construction material insulates. The higher the R-value, the better the insulation and the more energy you will save. An R-value only applies to specific materials, not to systems. When the entire system is considered, it is called the Effective R-value

• Transfer of heat through the building envelope decreases the level of thermal comfort and increases the heating energy requirements, which increases the operation costs of the house
• Properly insulating the home directly effects how comfortable the home is and how much energy the home will use
• Properly insulating reduces/eliminates cold spots in the building envelope. This increases the longevity of the home by reducing condensation problems