2006 has been a year of big change for the HVACR industry because of one key issue: 13 SEER. While the increase in minimum efficiency requirements has been a big story the past couple of years, the actual January 2006 implementation of the standard has shaken out several stories, namely matching the systems for the greatest efficiency, duct leakage, parts and equipment shortages, equipment fit, and 10-12 SEER inventory depletion.