I have a 1977 house...drywall with no insulation. It gets pretty chilly in here especially when windy. The walls are not insulated and it seems it would be quite a hassle to demo and replace just to add insulation in the exterior walls. A friend recommended just doing ceiling insulation and that would help a lot. Anyone have experience with this? Will adding insulation in the attic REALLY help or will I be wasting money and time? Thanks in advance.