If your attic has enough insulation and proper air sealing, and your home still feels drafty and cold in the winter or too warm in the summer, chances are you need to add insulation to the exterior walls. in an existing home, consider using blow-in insulation, which, when installed with the dense pack technique, will provide significant air sealing. Properly insulating your cathedral ceilings will allow ceiling temperatures to remain closer to room temperatures, providing an even temperature distribution throughout the house.