My wood frame house is approximately 21 years old. The insulation in the attic is the 'roll' type as is the same under the house. (House is on pillars approximately 4ft on one end and ground level on the other due to the ground slope). I have been replacing the insulation under the house with roll type but still notice you can feel colder air on your upper torso when walking around in the house. Would this type of insulation effectiveness degrade over 21 years? Thanks for helping.