The ASHRAE Standard 90.2 Energy Efficient Design of Low Rise Residential Buildings provides minimum requirements for such building designs. A revised version will be a joint effort between ASHRAE and the Illuminating Engineering Society of North America (IES). The aim of the revision is to strengthen requirements in Standard 90.2 following a recommendation in 2009 by ASHRAE’s board of directors for the standard to ensure 30% more energy efficiency than the 2004 version and include both a prescriptive and a performance path. The standard will be written in an easy-to-understand format that is simple to use. An advisory public review of the Standard is planned for late 2010 to determine whether proposed changes will meet the construction industry needs.