Use this calculator to demonstrate compliance with the prerequisite. The calculator accommodates all ventilation types (multiple zone, single-zone, 100% outside air) in one spreadsheet. Assumptions for occupancy categories are from ASHRAE 62.1-2010 (for LEED v4 projects) and ASHRAE 62.1-2007 (for LEED 2009 projects). The calculator has also been updated to include a LEED v4.1 option.