Understanding the Importance of Insulation
If you're like the vast majority of homeowners you're concerned about the costs of heating (and cooling) your home. There's a good reason for your concern, the US Department of Energy estimates that just under half (44%) of the energy used in the average American home goes toward either heating or cooling the home. However, there is some good news, the DOE estimates a homeowner may be able to reduce their heating bill by 10% to 50% simply by increasing the amount of insulation installed in their homes.
Why Insulation is Important
Air naturally tends to move from warm areas towards colder areas and insulation restricts this natural movement. So, during the cold season, insulation prevents cold from coming into the house through the ceilings or walls, (it works the same way during the hot summer, keeping the cool air inside the house and blocking it from moving towards the warmer area outside.
Where Should Insulation Be Installed?
Insulation should be installed in any barrier (wall or ceiling) the stands between cold air and warmer air or unheated spaces and hated spaces. So, in a typical home, the most important areas to have well-insulated are the ceiling, the walls and the basement. Crawl spaces and garages are also areas where insulation can be added to reduce heat loss.
Types of Insulation Available to DoItYourselfers
While many different materials are used for insulation in a home, the most common are fiberglass or rock wool bats or blankets, loose-fill (primarily cellulose) or foam (either rigid foam boards or blown).
Fiberglass or rock wool bats are easily installed in new construction (fit in between wall joists when finishing a basement) as well, both bats or blankets can be easily laid over the top of ceiling joists in an attic.
Loose-fill can literally be poured into between ceiling joists or added behind existing walls.
Foam boards can be cut to fit in between new construction wall studs or glued directly onto foundation walls.
Insulation is measured by its R-value, - it's resistance to heat flow. The higher the number, the more blocking capacity or insulating it provides. Different materials have different heat blocking capabilities, therefore different R-values. As well, the thickness of the insulation, where it's installed and how well it's installed will determine the total R-value of the insulation in your home. Since R- values are cumulative (they add together) the total R-value is the sum of the R-values of the insulation in any particular area of your home.
How much insulation should my home have?
The Department of Energy provides ranges of recommended minimum values for homes depending on where they're located.
Mild climates - R-11 in the walls and floors and R-19 in the ceilings
Moderate climates - R-19 in the walls and floors R-30 in the ceilings
Cold climates - R-19 in walls and floors and R-38 to R-49 in ceilings
Keep in mind these are only minimums and provide a rough estimate. More specific recommendations insulation levels to achieve maximum for your home (by ZIP code) can be obtained by contacting the Department of Energy web site at http://www.ornl.gov/~roofs/Zip/ZipHome.html