ASHRAE has released the 2013 version of ANSI/ASHRAE Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. According to ASHRAE, this standard is the only nationally recognized indoor air quality standard developed solely for residences. Its main purpose is to define the roles of, and minimum requirements for, mechanical and natural ventilation systems, and the building envelope intended to provide acceptable indoor air quality in low-rise residential buildings. The most significant change affecting our industry (verses the 2010 version), is the increase in mechanical ventilation rates to 7.5 cfm per person plus 3 cfm per 100 square feet. For example, for a typical three bedroom, 2500 square foot home, the mechanical ventilation rate increased to 105 cfm, up from 60 cfm in the 2010 version. In the 2010 version, it was assumed that 2 cfm per 100 square feet came from infiltration, which later was determined to be incorrect, as based upon better research. This research found that homes have gotten tighter and that apartments have always been tight. According to ASHRAE, the 2013 version drops the infiltration contribution, and the entire amount of ventilation must be supplied mechanically. Here is the link to the ASHRAE Press Release.