Window placement is not primarily an aesthetic decision. The height of a window's head, the position of its sill, its distance from adjacent walls — these determine the geometry of light in the room it serves. Sun angle, which changes with latitude, season, and time of day, is the other variable. Together, they define whether a room is luminous and thermally comfortable, or glare-prone and underlit.
The Head Height Rule and Why It Matters
The most useful rule in residential window placement is the relationship between head height and light penetration depth. Light enters through a window at the angle of the sun or sky — for diffuse daylight, that angle averages roughly 30 to 45 degrees above horizontal. At those angles, the depth of useful illumination from a window is approximately two to two-and-a-half times the window head height, measured from the exterior wall inward.
A window with a head height of 2.4 meters illuminates useful daylight to roughly 5 to 6 meters of floor depth. A room 8 meters deep will have a dark zone at its rear that window glazing alone cannot reach. Extending the head height to 3.0 meters pushes the light boundary out to 6 to 7 meters. Adding a clerestory at 3.5 meters can extend it further still.
This rule applies to diffuse sky illumination. For direct sun penetration, the geometry shifts with the sun angle — and that sun angle is different for every latitude and every season.
Sun Angle Geometry by Latitude
At Mexico City's latitude of approximately 19 degrees north, the sun passes nearly overhead at summer solstice. The noon sun altitude at solstice is about 88 degrees — almost vertical. A south-facing window on a summer day in Mexico City receives almost no direct sun because the sun is directly above. The challenge is not blocking summer sun but controlling the glare from a bright sky reflected off horizontal surfaces.
At Denver's latitude of 39.7 degrees north, the solar geometry is different. The summer noon sun altitude is about 74 degrees — high but not overhead. Winter noon sun altitude drops to approximately 27 degrees — a shallow, raking light that enters south-facing windows at a steep horizontal angle and travels deep into rooms. This is the passive solar geometry that makes south-facing glazing effective in Colorado.
These latitude differences determine how windows should be placed and what overhangs are needed. An overhang designed for Mexico City's sun angles will underperform in Denver, and vice versa. We calculate overhang geometry for the specific latitude and altitude of each project.
Placement in Plan vs. Placement in Section
Window placement is discussed in two dimensions: plan position (which wall, which zone of the wall) and section position (head height, sill height, depth of reveal). Both dimensions matter.
Plan position determines which part of the room receives the incoming light. A window centered on a wall creates a symmetric light distribution. A window pushed to one side creates an asymmetric distribution — one wall is brightly illuminated, the other remains in relative shadow. This asymmetry can be designed deliberately, creating a spatial hierarchy in a room that appears uniform on the floor plan.
Section position determines light depth, glare risk, and thermal behavior. A high window with a deep sill creates a shaft of light that enters the space from above — more like a skylight in character than a traditional window. A floor-to-ceiling window maximizes light quantity but requires a shading strategy to manage glare at low sun angles, particularly on east and west exposures.
At MÉTODO, window placement decisions are made in both dimensions simultaneously, in plan and section drawings developed in parallel.
Glare Management by Window Geometry
Glare is a function of the luminance difference between the window and the surfaces adjacent to it. A small, bright window against a dark wall creates maximum contrast — maximum glare. The same window area distributed as a broader opening with lighter surrounding wall finishes reduces the contrast.
Window placement and reveal depth work together to manage glare. A deep reveal in stone or concrete — the natural consequence of building with heavy materials — casts shadow around the window perimeter, reducing the luminance contrast between the bright exterior and the dark wall surface inside. The reveal is not ornamental. It is performing glare control.
In residential design, this glare management happens at the section scale: the depth of the wall at the window, the angle of the reveal faces, the finish of the interior reveal surface. These details, visible in a section drawing, determine whether a window is comfortable to sit near or requires constant shading.
The Matrix of Options for Window Configuration
When we design window placement for a residence, we use the matrix of options to compare configurations before committing to one. A typical matrix for a main living space might compare:
- High clerestory plus low fixed glazing (maximum light depth, controlled glare)
- Full-height glazing with exterior horizontal fins (maximum view, managed solar gain)
- Deep-reveal punched openings at seated eye level (intimate scale, minimal glare)
- Corner window condition (dramatic but thermally and structurally complex)
The matrix makes the trade-offs explicit: light depth versus glare risk, thermal performance versus view quality, structural simplicity versus spatial drama. The client decides from the matrix with full information.
Next Steps
Window placement — head height, sill position, reveal depth, and orientation — is a design decision with consequences that cannot be easily corrected after construction. Getting it right requires solar geometry specific to the site's latitude and altitude, and a section analysis that shows the light behavior before anything is built.
Explore how MÉTODO brings this level of specificity to every design decision in our residences and cultural projects.