As a significant source of heat loss, your attic has a lot of potential for helping you save money and live more comfortably all year round. The effectiveness of your insulation, however, depends on its R-value (and proper installation, of course). What is the right attic insulation R-value for your home?
What Is Insulation R-Value?
R-value is an efficiency rating for insulation. It refers to a particular insulation’s ability to resist heat flow. R-values vary based on:
- Material
- Density
- Thickness
The higher the value, the more insulating ability the product has. To achieve a higher attic insulation R-value, simply add another layer of insulation.
How Much Insulation Does Your Attic Need?
Different areas of your home have different R-value recommendations, and homes in different areas of the country have different recommendations based on the climate and cost effectiveness of the insulation.
For homes in the Huntsville, Alabama area, the attic should achieve an R-value between R-25 and R-60, depending on the current insulation levels. In addition to climate, R-value also depends on the age of your home.
Nominal R-Value vs. Effective R-Value
The R-value indicated on the packaging tells how much thermal resistance the insulation provides per inch. Of course, this number is merely the nominal R-value. Other factors in the real world impact how well the insulation lives up to its rating.
Installation
If the insulation needs to be compressed so it fits into the space, this decreases attic insulation R-value by minimizing air pockets within the product and thus lowering its thermal resistance.
Temperature
A variety of insulation types—including fiberglass batts, expanded polystyrene (EPS) and extruded polystyrene (XPS)—can be more effective when the temperature drops outside. Oddly, when it’s above 60 degrees, the insulation can perform below its nominal R-value.
Temperature has the opposite effect on one popular type of insulation called polyisocyanurate, often simply called polyiso. This insulation decreases in R-value as it gets colder outside. Solutions for this problem include using more polyiso, covering it with another type of insulation to keep it warmer, or counting on exterior insulation instead of cavity insulation to meet your requirements.
Attic Insulation for Northern Alabama Homes
This is a lot of information, but keep in mind that you won’t be on your own! Professionals can complete your insulation installation so it’s done correctly. The team at American Insulation installs high-quality spray foam and fiberglass insulation. If you’re looking to boost your attic insulation R-value, contact us today!
