In most states, homes that are over 10 years old are under insulated. This is, in part, due to settling of the insulation and partly due to traffic through the insulation. Other causes may be due to homeowner misuse. Homeowners can sometimes store items directly on the insulation. This compresses the insulation and reduces the thermal resistance of the insulation. Look for our future report on why you should NEVER store items in your attic.
13 inches is code for regions like Texas, Georgia, Louisiana, and Mississippi. So if you use a tape measure and find , on average, you are below this level, you should call a professional. The term "R" Value refers to the "Resistance" value of the insulating material. The higher the "R" value The better your home can manage thermal transfer. In other words, you will keep the heat out in summer and keep the heat IN during winter.
So why not fill the entire attic with insulation from floor to roof? Because your attic needs another ingredient to manage heat transfer. And that is Airflow. Airflow allows for convection heat to escape your attic. This reduces the differential between the air in your home and the air in your attic. This is what helps keep humidity levels to a norm in your home. We will talk about the 3 types of heat in another post.
So, if you want to save on energy bills this season, preserve the life of your roof and the systems in your attic and make your home more evenly comfortable, you should take a look and see if you are under insulated and then call a professional if you are not.
Attic Buddies Insulation is a good place to start.