The first consideration in solar home design is to:

Building orientation is the most fundamental and primary consideration in passive solar design. It is the foundational decision upon which all other strategies are based. The building's orientation dictates which facades receive solar radiation and at what times of day and year. This, in turn, informs critical subsequent decisions, including the placement and specifications of windows (glazing), the design of solar shading (overhangs), and the strategic location of thermal mass to absorb and release heat. Optimizing orientation, typically by elongating the building on an east-west axis in the Northern Hemisphere, is the most cost-effective way to maximize beneficial winter solar gain and minimize unwanted summer heat.

A. Select windows: Window selection (e.g., SHGC, U-factor) is a critical but secondary step that depends on the solar exposure determined by the building's orientation.

B. Size solar shading: Shading elements are designed specifically to block or allow sunlight based on solar angles, which are a direct function of the building's orientation.

C. Incorporate thermal mass: The placement and quantity of thermal mass are determined by where direct sunlight will enter the building, a direct result of its orientation.

1. U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy. Passive Solar Home Design. Energy.gov. Accessed 2023. The document states, "In the Northern Hemisphere, the south side of a building always receives the most sunlight. Therefore, the first principle of passive solar design is to orient a building to face south to maximize solar heat gain." (Section: "Orientation").

2. US Green Building Council. LEED v4 for Homes and Multifamily Reference Guide. Washington, D.C.: USGBC, 2016. The guide emphasizes an integrative process where passive design is a primary consideration. Under EA Credit Annual Energy Use, it lists "Orient the building to control solar gain" as a key passive design strategy that should be considered early in the design process to reduce energy loads. (p. 178, "Passive design strategies").

3. Lechner, Norbert. Heating, Cooling, Lighting: Sustainable Design Methods for Architects. 4th ed., John Wiley & Sons, 2014. This university-level textbook on sustainable design establishes a clear hierarchy, stating, "The first step in designing for the sun is to orient the building properly." (Chapter 6: "Passive Solar," Section 6.3: "The Five Elements of Passive Solar Systems," p. 205).