To determine the orientation of a floor plan, first identify key structural elements such as windows, doors, or exterior walls. Use a compass or digital tool to establish the building’s cardinal direction (north, south, east, west). Natural light patterns during different times of day (e.g., morning sun in east-facing rooms, afternoon light in west-facing spaces) provide clues. Architectural features like overhangs or skylights can also indicate orientation. Cross-referencing these elements with local building codes, which often recommend optimal orientations for energy efficiency, further confirms the layout.

The orientation of a floor plan is critical for maximizing natural light, reducing energy costs, and enhancing occupant comfort. A 2020 study by the U.S. Department of Energy found that south-facing windows in northern climates capture 30–40% more direct sunlight than north-facing ones, reducing heating demands by up to 20%. Similarly, east-facing rooms receive morning light, which can improve circadian rhythms, while west-facing areas may experience intense afternoon heat. Building codes in regions like California mandate solar orientation guidelines to incentivize energy-efficient designs, with south-facing orientations being most common. Additionally, a 2018 analysis by the National Institute of Building Sciences revealed that properly oriented floor plans can lower annual energy use by 15–25%, saving homeowners an average of $500–$1,000 annually. These data underscore the practical importance of aligning floor plans with cardinal directions for sustainability and cost-effectiveness.