Effective July 1, 2011: For new construction and additions to state buildings, the energy efficiency provisions (Chapter 13) of the 2006 International Building Code (IBC) will be replaced by ASHRAE Standard 90.1-2007.
State energy codes are passed through the legislature and apply to all construction. They must be adopted locally before they are enforced.
The state fire marshal's office will require a state building permit for new residential construction in areas of the state except those where an exempt local government is enforcing a residential building code or where the local government has notified the department it has opted out of the law. Single family and two family residences, townhomes and site built construction for manufactured and modular homes will be required to have a building permit prior to commencing construction. Permits will only be required for new construction or a change of use to residential and NOT for renovations. Permits must be placed on site during the construction until the certificate of occupancy is issued and are valid for two years. The department will verify contractors' licensure as part of the permitting process. Owners' permits will be limited to one in a 24 month period.
The State Fire Marshal's Office implements enforcement of the adopted codes. TN Notice of Enforcement.  
Compliance can be demonstrated during plan review and verified by local inspection. Some jurisdictions may accept the registered design professional's seal on a letter stating that the design complies with the code.
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.
In the first quarter of 2003, the governor presented new legislation to add the 2000 International Energy Conservation Code with 2002 Amendments to the statewide energy code for low-rise residential buildings. This legislation was subsequently introduced as HB 2009/SB 1981 in the 2003 legislative session.
Tennessee is a "home rule" state which leaves adoption of codes up to the local codes jurisdictions. As such, Tennessee cannot "mandate" the adoption of codes. The legislation, which gave local codes jurisdictions an option of wither continuing to use the 1992 MEC or upgrading to the 2000 IECC with 2002 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.
The Tennessee Department of Commerce and Insurance (State Fire Marshal's office) began a residential building code enforcement program on October 1, 2010. This program covers areas of the state that do not have building codes enforced by the local government or do not enforce building codes that are current within seven years of the latest edition unless the local government has opted not to have the state do so.
In order to improve the safety and energy efficiency of homes, the state has adopted and will be enforcing the 2009 International Residential Code (IRC) and the 2006 International Energy Conservation Code (IECC). Fire sprinklers will not be required in one and two family houses. These building codes apply to: new residential construction (not renovations) or change of use to residential beginning on or after October 1, 2010.