This handbook is intended as a guide for engineers, architects, and individuals familiar with heating and ventilating applications who wish to design a solar heating system for a residential or small commercial building in the Pacific Coast Region. The climate of the region is discussed by selected cities in terms of the effect of climate on solar heating requirements. The four states covered are California, Oregon, Washington, and Arizona. Presented in detail are the design parameters and performance characteristics of liquid space heating systems of the active type using flat plate collectors, water heat storage, and forced air distribution; active air space heating systems using flat plate collectors, rock-bed storage, and forced air distribution; and domestic hot water heaters of the active type using liquid-cooled flat plate collectors. The analyses are based on hour-by-hour computer simulations using actual weather data from six selected cities. The collector area required for the three types of active systems has been determined as well as the effect of changes in all the design parameters. A simple, empirical, monthly solar-load ratio method for determining collector area is described and results are presented for 13 additional locations within the region. Swimming pool heaters are described briefly, and passive space heating systems are discussed qualitatively in terms of a number of successful designs. (Author)