1.7 Climate Zones
To standardize calculations and provide a basis for presenting the prescriptive requirements, the Energy Commission has established a set of standard climate data for each of the 16 climate zones. More information is provided in Reference Joint Appendix JA2 (also included in Appendix B of this document), including a listing of climate zones for all California ZIP codes. Reference Joint Appendix JA2 gives other climate information, such as design temperatures for sizing HVAC equipment. The climate zone definitions and data are the same for single-family residential, multifamily, and nonresidential standards.
Figure 1-1: California Climate Zones
1.7.1 Building Location Data
Building location data refer to specific outdoor design conditions used in calculating heating and cooling loads. Different from the climate zone used for compliance (see Climate Zones above), design data include the typically warmest and coolest outdoor temperatures that a building is likely to experience in an average year in a particular location.
Temperatures are from the ASHRAE publication, SPCDX, Climatic Data for Region X - Arizona, California, Hawaii, Nevada, May 1982 edition. (See Appendix E.) For heating, the outdoor design temperature is the Winter Median of Extremes. A higher temperature is permitted but no lower than this value. For cooling, the outdoor design temperatures must be the 1.0 percent Summer Design Dry Bulb and the 1.0 percent Wet Bulb columns.
If a building location is not listed, the local enforcement agency may determine the location for which data are available that is closest in its design characteristics to the actual building site.