The International Energy Conservation Code (IECC) is a model residential and commercial building energy code produced by the International Code Council, an organization dedicated to building safety and fire prevention. The IECC provides a list of requirements and minimum standards regulating building design, including lighting and other energy-using systems. As a model code, it is intended as a template and has no regulatory effect until a legal jurisdiction adopts it in whole or as modified.

The IECC references ASHRAE/IES 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, currently the national energy standard, as an alternative. Today, most states have a commercial building energy code in place based on IECC and ASHRAE/IES 90.1 and at least as stringent as ASHRAE/IES 90.1 2004.

First published in 1998, the IECC was updated in 2000, 2003, 2006, 2009 and 2012. The latest version more strongly differentiates residential and commercial requirements in two separate sections. In terms of lighting, the residential provisions are relatively simple. The main requirement is that at least 75 percent of the lamps in permanent lighting fixtures must be high-efficacy, which the code defines as T8 or smaller diameter linear fluorescent lamps or lamps with a minimum efficacy of 40 lumens per watt (LPW) for <15W, 50 LPW for 16–40W, and 60 LPW for >40W lamps.

On the commercial side, the code contains both mandatory and prescriptive lighting provisions. The mandatory provisions require tandem wiring in certain fluorescent applications; maximum wattage for exit signs; circuiting for daylight harvesting control; and automatic shutoff, light level reduction and other controls. The prescriptive provisions establish limits on lighting power, and the designer and owner ultimately decide how best to accomplish the lighting goals within the power constraint.

New provisions
Many lighting-related provisions are new in IECC 2012. Note that for each new feature, exceptions may apply; consult IECC 2012 for specific details.

Occupancy sensors are now specifically required in a series of spaces, including conference/meeting rooms, classrooms, lunch/break rooms, private offices, restrooms, storage rooms, custodial closets, and other enclosed spaces 300 square feet or smaller. The occupancy sensor must turn the lights off within 30 minutes of vacancy and feature manual-on or auto-on-to-<50-percent operation.