subject: What The R-value Of Insulation Means [print this page] All insulation sold in the United States must be rated with an R-value. The R-value of insulation refers to ability of the insulation to resist heat flow. Insulation that is in rolls, loose-fill, rigid foam, or foam-in-place will have an R-value that corresponds with heat flow resistibility. As the numbers of the R-value increase, the level of resistance increases. That means that R-49 insulation will be more effective than R-38 insulation.
R-Value When Layering Insulation
The thickness of the insulation is a factor when determining the R-value. As the thickness of the material increases, the thermal resistance increases. You can double the R-value by installing two layers of insulation of the same R-value. It is recommended that a home in colder regions should have insulation with an R-value of 49 and homes in warmer regions should have insulation with an R-value of 38. The R-value of pellet and loose-fill variants is measured in per-square-inch and in per-inch for fiberglass rolls. For example, you can install blow-in cellulose pellet insulation with a rating of R-3.5 per square inch, or fiberglass rolls with a rating of R.3.2 per inch. The construction of the home may dictate how much insulation you can install. For instance, some areas of the home may only allow you to install one layer of insulation and other areas may allow you to install more. Only install the number of layers that the framing of the home will allow you to install. Doubling the insulation in an area that is only intended for one layer will not result in a doubling of the R-value, but it will be increased.
Factors that Affect the R-Value
Some people do not account for the windows, joists, and studs when determining which R-value to use. Heat flows around the insulation through the studs and joists and heat is often lost around the windows. This will create slight differences in the R-value of the insulation and the R-value of the wall. You should make sure that the insulation is properly installed in these areas and that the insulation is not packed too tightly. Tightly-packed insulation will not provide the full R-value. Heat loss through glass windows and the ventilation system will also affect the R-value of the wall.
What to Remember When Installing Insulation
The most important thing to remember when installing insulation is to wear safety equipment. You should wear a dust mask, eye protection, gloves, and long sleeves when working with fiberglass insulation. The fiberglass particles have the capacity to lacerate the eye and it will irritate your skin. It can also create tiny cuts in the lungs, trigger an asthma attack, or inflame the delicate tissue if it is inhaled. When installing attic insulation, you should make sure that you do not install over can lights or any other light fixture that is not rated to withstand contact with insulation. Contact of the insulation with inappropriate lights could cause a fire. If you are installing window insulation, you should make sure that you completely fill in the cracks around the windows to prevent heat loss. Make sure that you do not over-pack the spaces. If you are going to have a professional handle the job, get several quotes from reliable contractors before you make a decision.
