Tennessee's first energy code, the 1977 Model Code for Energy Conservation (MCEC), was adopted by the legislature in 1978. This code was in effect until July 1, 1994, at which point the 1992 Council of American Building Officials (CABO) Model Energy Code (MEC) was adopted pursuant to Public Chapter 193, HB 641. Legislation giving local codes jurisdictions an option whether continuing to use the 1992 MEC or upgrading to the 2000 IECC with 2001 Amendments was passed on May 28, 2003 and signed by the governor on June 11, 2003. It took effect on July 1, 2003.
On May 14, 2008 the state legislature amended Public Chapter No. 907 by establishing the 2003 IECC as the mandatory minimum energy conservation standard for new residential construction on or after January 1, 2009. The law strongly encourages builders to voluntarily adhere to the 2006 IECC standards for residential and commercial construction. On June 25, 2009, Governor Phil Bredesen signed SB 2300 (now Public Chapter 529), placing residential energy efficiency codes under the purview of the State Fire Marshal, who shall select the specific ICC code edition to be implemented. The bill does not reference the IECC, instead establishing the IRC and IBC as adopted codes. During debate on the bill, the state House considered roughly 20 amendments to SB 2300, attempting to allow counties to opt out of the state residential code. An amendment containing a sunset provision for 2014 was approved. The codes provisions of the bill now also include a mechanism through which local legislative bodies can "opt out" their communities with a two-thirds vote. Additionally, for communities that have somewhat outdated codes programs, the state will provide incentives in the form of free training and materials to encourage them to update their standards.
On June 2, 2011, the Tennessee State Fire Marshal’s Office announced that it would begin the implementation and enforcement of adopted energy codes for new building project submissions as of July 1, 2011. These include ASHRAE Standard 90.1-2007 for all state buildings and the 2006 IECC for all other residential and commercial construction. Information on compliance certificates and other requirements can be found here.