This first article in a series about attic insulation covers the concept of R-value as it applies to insulation and then discusses the importance of making sure your insulation meets the standards of your local building code.
Heat naturally flows from a warmer area to a cooler one. It does this in only three ways: conduction, where heat is transferred directly from mass to mass; convection, the movement of heated air from one space to another (hot air rises, heavier cool air sinks); and radiation, which simply means that any warm body gives off heat toward a cooler one. The function of insulation is to minimize the transfer of heat by any of these methods.
This section will discuss the merits and uses of various types of well-known insulations and inform you on how best to evaluate R-values.
R stands for 'resistance to heat flow.' The greater the R-value, the greater the insulative power. R-value requirements depend on factors such as local climate and the surface you are insulating (walls, ceiling, floor, etc.) and will be regulated by your local building code. Contact the office of your city or county building inspector for the requirements of your area. Each region of the country has different requirements for adequate amounts of insulation.
In most areas (see weatherizing section), local utility companies will offer helpful suggestions on how to reduce your energy bills. Many will arrange to have an expert come to your home to point out areas that need to be insulated or weatherized. Often there is no charge for this service. It may even help you learn about applicable low- or no-interest loan programs and state or federal tax credits for installing better insulation.
Check with your State Energy Commission, local power company, or local home center for the optimum R-value in your region.
OK! With those considerations in mind, it's time to get your gear in order. Part 2 in this series lists all the tools you will need to install any type of attic insulation or ventilation.