Good insulation can keep a house cozy in winter, and cool in summer--while saving money and conserving energy. In amazingly thorough detail, with plenty of color illustrations, William P. Spence, author of such bestsellers as Carpentry and Building Construction, describes every step of insulating, sealing, and ventilating your home. He shows how to determine the amount of insulation needed, locate air leaks, regulate air quality, and determine the costs versus benefits of any job. Find out where to start work, which materials are most effective, and how to handle potential insulation problems. From air-sealing external walls to adding vapor barriers, all you need to know is here.