Sun Angles in Canada
Canada spans a wide range of latitudes. At Ottawa (approximately 45°N), the solar altitude at solar noon on the winter solstice is around 21°. At the summer solstice it reaches roughly 68°. In Vancouver (49°N) the winter solstice noon sun sits at about 17°; in Whitehorse (60°N) it barely clears 7°. These figures matter because they determine how deep direct sunlight penetrates through a vertical window.
A standard 900 mm high window in a south-facing wall will admit direct sunlight to a much greater floor depth in summer — when the sun is high — than in winter, when the low-angle sun can actually penetrate further under an overhang but at a shallower angle. The Natural Resources Canada building energy guidance addresses solar gains in Canadian buildings and provides reference data for different climate zones.
Orientation
South-Facing Windows
South-facing windows (in the northern hemisphere) receive the most total solar radiation over the year. In winter, when the sun is low, south glazing admits direct solar heat gain — useful for passive solar heating in cottages that are occupied year-round. In summer, east–west overhangs can block high-angle direct sun while still admitting diffuse sky light. South-facing glazing is generally the most valuable in Canadian cottages for both light and passive heat gain.
North-Facing Windows
North-facing windows never receive direct sunlight (in the northern hemisphere). They deliver diffuse sky light — even, consistent, and glare-free throughout the day and year. For studios, reading rooms, or spaces where consistent illumination without seasonal variation is preferred, north glazing is often the better choice. The trade-off is no solar heat gain, which in Canadian winters is a meaningful energy consideration.
East and West-Facing Windows
East windows admit morning sun; west windows admit afternoon sun. Both introduce low-angle direct light, which creates glare for part of the day and is difficult to control with fixed overhangs. They are useful for bedrooms or breakfast areas where morning light is desirable, but challenging in workspaces or living areas occupied throughout the day.
Canadian Climate Note
In Canadian cottage country — Muskoka, the Laurentians, the BC Interior — tree canopy significantly affects available light. A window that appears south-facing on a plan may receive substantial shading from existing mature trees. Site observation across different seasons, or a solar path analysis tool, helps assess actual direct sun access before committing to a window strategy.
Window Placement Height
A window's position in the wall determines how far light travels into the room. Light entering at sill level illuminates a narrow band near the window. The same window area placed higher on the wall — with a higher head height — delivers light to a greater floor depth. Clerestory windows (placed above the typical head height, often near the ceiling) are particularly effective for delivering daylight into room interiors without sacrificing wall space for furniture.
In cottage renovation, raising the head height of an existing window opening — while keeping the same sill height — increases both the window area and the depth of natural light penetration simultaneously.
Glazing Properties
Modern window glazing is described by several performance metrics relevant to daylighting:
- Visible Light Transmittance (VLT): The fraction of visible light that passes through the glass. A VLT of 0.70 means 70% of visible light is transmitted. Higher VLT delivers more daylight. Some low-emissivity coatings reduce VLT; it is worth checking this value when comparing window units.
- Solar Heat Gain Coefficient (SHGC): The fraction of solar energy that enters through the window. In Canadian conditions, a higher SHGC on south-facing windows is generally beneficial in winter. On north windows, SHGC is less relevant since direct solar exposure is minimal.
- Double vs. Triple Glazing: Triple glazing is increasingly standard in Canadian new construction for its superior thermal performance, but it typically has a lower VLT than double glazing of equivalent area. Where daylighting is the priority in a mild-climate cottage, double glazing with a high-VLT coating may deliver more light per unit of area.
Window-to-Floor Ratio
A rough benchmark from building codes and energy standards is that a window area of 10–15% of the floor area is sufficient for adequate natural light in most living spaces. In cottages where energy performance is less critical and daylighting is a design priority, ratios of 20–25% are common. The National Building Code of Canada sets minimum glazing requirements for habitable rooms; these are floors, not targets.
Obstructions and Reflections
Light entering a window is reflected and absorbed by nearby surfaces before reaching the room interior. A light-coloured sill reflects incoming light upward into the room; a dark sill absorbs it. External light-coloured surfaces — a pale deck, light gravel, snow — bounce additional light upward into the window, effectively extending the daylighting season. Conversely, nearby dark surfaces, dense vegetation close to the glass, or overhangs that are too deep for the latitude all reduce incoming light.
Last reviewed: May 2026. References: Natural Resources Canada, National Building Code of Canada, U.S. DOE Daylighting Reference.