The minimum required outdoor air ventilation is calculated based on the conditioned floor area of the home and the:

The LEED for Homes rating system requires projects to meet the ventilation rates specified in ASHRAE Standard 62.2, "Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings." The formula in this standard for calculating the required whole-dwelling mechanical ventilation rate is based on two primary factors: the home's conditioned floor area and the number of bedrooms. The number of bedrooms is used as a standardized proxy for the potential number of occupants, ensuring the ventilation system is sized appropriately for the home's designed capacity, regardless of the actual number of current residents.

A. The volume of the home is used for calculating air infiltration rates (e.g., ACH50) but not for the ASHRAE 62.2 continuous ventilation rate formula.

C. The number of bathrooms dictates requirements for local mechanical exhaust ventilation (spot ventilation), not the whole-home continuous ventilation rate.

D. The number of bedrooms is the specific metric used in the ASHRAE 62.2 formula as a proxy, not the actual number of full-time occupants, which can vary.

1. U.S. Green Building Council. (2021). LEED v4.1 Residential Building Design and Construction. Washington, DC: USGBC. In the Indoor Environmental Quality (EQ) section, Prerequisite "Minimum Ventilation" and Credit "Enhanced Ventilation" both reference compliance with ASHRAE Standard 62.2.

2. ASHRAE. (2016). ANSI/ASHRAE Standard 62.2-2016: Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. Atlanta, GA: ASHRAE. Section 4.1, "Whole-Building Ventilation," provides the formula for the target ventilation rate (Qtot) as a function of floor area (Afloor) and the number of bedrooms (Nbr): Qtot = 0.03 Afloor + 7.5(Nbr + 1).

3. Bailes, A. (2012). A House Needs to Breathe...Or Does It? [Course Material]. MIT OpenCourseWare, 4.462 Building Design and Technology II. The course materials discuss residential ventilation strategies, referencing the ASHRAE 62.2 standard's reliance on floor area and bedroom count for calculating required mechanical ventilation rates. (Note: While the course is from 2012, the fundamental principle of the 62.2 calculation remains consistent in subsequent versions referenced by LEED).