Comparison of ASHRAE Standard 90.1, 189.1 and IECC Codes for Large Office Buildings in Texas

Abstract

Six energy codes were compared in terms of annual site and source energy consumption. This comparison includes ASHRAE Standard 90.1-1989, ASHRAE Standard 90.1-1999, ASHRAE Standard 90.1-2007, ASHRAE Standard 90.1-2010, IECC 2009 and ASHRAE 189.1-2009. The analysis was performed for three Texas counties: Harris (climate zone 2A), Tarrant (climate zone 3A) and Potter (climate zone 4B). Both annual site and source energy consumption were compared. ASHRAE Standard 90.1-1989 was considered as the base case.

ASHRAE Standard 90.1-1989 was considered as the base-case. When considering site energy consumption, ASHRAE Standard 90.1-1999 provides an improvement of 16.7%-18.6%. ASHRAE Standard 90.1-2004 provides an improvement of 22.3%-32.6%, ASHRAE Standard 90.1-2007 provides an improvement of 28.1%-33.9%, IECC 2009 provides an improvement of 27.4%-35.3%, ASHRAE Standard 90.1-2010 provides an improvement of 42.1%-47.7%, and ASHRAE 189.1- 2009 provides an improvement of 46.9%-54.9% above the ASHRAE Standard 90.1-1989 base-case.

When considering source energy consumption, ASHRAE Standard 90.1-1999 provides an improvement of 14.5%- 15.0%, ASHRAE Standard 90.1-2004 provides an improvement of 21.6%- 27.2%, ASHRAE Standard 90.1-2007 provides an improvement of 23.5%-28.4%, and IECC 2009 provides an improvement of 23.4%-30.5%. ASHRAE Standard 90.1-2010 provides an improvement of 41.8%-45.7% and ASHRAE 189.1-2009 provides an improvement of 44.5%-51.8% above the ASHRAE Standard 90.1-1989 base-case.