What is wrong with the current climate zones?
The existing climate zones suffer from several shortcomings that the new zones attempt to remedy: • Too many zones within individual jurisdictions. Many code users have complained to DOE that the code’s requirements change too much within code jurisdictions. Reducing the number of zones by roughly half will mean that far fewer users will need to keep track of requirements that differ across the region in which they practice. • Poor representation of cooling issues. The existing zones are based entirely on heating degree-days, which means they do a rather poor job of distinguishing climate factors that affect cooling loads. The new zones better reflect factors that impact cooling, such as cooling degree days, high wet bulb temperatures, and variations in solar radiation. • Inconsistent use in the code. The existing climate zones are not used consistently in the IECC. For example, the IECC’s residential requirements are mostly based on heating degree-days, while its commercial requiremen
