Passive heating takes advantage of sunlight as a natural energy source. If a home is oriented to the south, the low-angled winter sun provides heat even in not-so-sunny climates. Overhangs protect the home from the sun's heat in summer, and good insulation and an internal thermal mass, such as masonry, complete the most basic passive heating and cooling system.
In The Solar House: Passive Heating and Cooling (Chelsea Green Publishing Co., 2002), author Daniel Chiras explains the fundamentals of integrated passive design. The 267-page book provides region-specific design for heating and cooling as well as worksheets, recommendations and software suggestions to help design and assess the performance of passively conditioned homes.
The Solar House is available for $29.95 from Chelsea Green or at www.HousingZone.com/store/.