This article is about the northern orientation of rooms and how the big absentees - the direct rays of sunlight - set the stage for indirect daylight. What concerns all orientations on cloudy days is 'business as usual' with northern light: cool and shadow-free, diffuse light. When reading, bear in mind that the content relates primarily to Switzerland as a location with a pre-alpine climate. However, the basic principles can be applied to any location, taking into account the location, sun path and local climate.
Only shade, no sun?
North-facing facades are often associated with shadow and lack of sunlight. While this is generally true in our latitudes, it is important to note that these facades can still receive some direct sunshine. During the summer months, the sun rises and sets north of the exact east or west. This means that an unshaded north-facing facade can receive up to a maximum of 6 hours of direct sunlight on a summer day. This usually happens in the early morning hours until 9 am at the latest and in the evening from 5 pm to sunset.
How is daylight from the north special?
In the summer months, when the sun makes it around the corners of the building, it bathes north-facing facades in warm reddish sunlight with its first and last rays of sunshine. Then the light character changes suddenly and dramatically. The uniformly diffuse light is transformed into direct light, which leads to a high-contrast and dramatic lighting mood in indoor and outdoor spaces. Due to the low position of the sun, long and distorted shadow images are formed. The shadows change constantly and move quickly, sometimes the scene is over after just a few minutes.
Apart from these brief appearances of the sun, northern light is characterized by its constancy and uniformity. Thanks to the absence of the sun, the incoming daylight consists solely of the diffuse part of daylight, a soft, low-shadow, and cool light. Thanks to the absence of direct sunlight, light from the north is less dependent on weather, time of day, or season. This gives it an extremely constant and timeless character and creates spaces of calm and focus.
Which rooms benefit from a northern orientation?
The soft, non-directional light comes across as calm and introverted. These features are particularly suitable for rooms where calmness, concentration, and focus are paramount and where little distraction or variety is desired. Examples of this are libraries and sacred spaces. Workshops and artists' studios are also often lit with north-facing openings because they benefit from constant, directionless, and low-shade lighting. The same applies to galleries and museums, where cool, soft, and uniform daylight is used almost exclusively. Direct sunlight has a higher potential for damage and it prevents a controllable and neutral presentation of the exhibits.
The diffuse daylight and the faint rays of sunlight that reach the north façade have a low radiant energy. North-facing areas can therefore hardly achieve solar heat gain in our latitudes. As a result, these rooms dissipate more energy from the building than it supplies. Due to the lower solar gain, spaces where we only spend time occasionally, such as ancillary or transit rooms, are well suited for a northern orientation. For rooms with high internal heat loads, such as canteen kitchens, and industrial or computer rooms, the low solar heat gain can be a good balance.
Konsthall Malmö by Klas Anshelm was opened in 1975. The exhibition area is illuminated by a large north-facing shed roof. In the lower areas, daylight is captured by over 500 skylights and directed into the room via cupolas. The skylights also face north, but they catch more direct sunlight due to their shallower angle and allow a interplay of direct sunrays and the diffuse component. Malmö Konsthall, 55° latitude, Photos: ©Helene Toresdotter / Malmö konsthall, Screenshot Google Maps
What needs to be considered when planning rooms on the north facade?
Inadequately lit rooms can look gloomy or develop a cave-like character. This risk exists when there is a large contrast ratio between the perceived brightness in the interior and the outside. To avoid this, the rooms must be sufficiently and evenly lit. Diffuse daylight is available in abundance for rooms on north-facing facades, and even for workspaces good illumination levels can be guaranteed in any interior, if daylighting is taken into consideration. The tools to achieve good lighting lie in architecture: the geometry of the room, as well as the dimensioning and positioning of the facade openings, are two of the most important factors for the supply of daylight indoors.
External sun protection is usually not necessary, glare protection on the other hand can be useful, depending on the use of the space. Since the sun has a very low position, vertical shading elements, such as blinds, are suitable. As the sun enters the rooms from the sides, vertical slats or angled panels can also be helpful in some cases.
In contrast to the other orientations, rooms on the north facade can benefit from a building opposite in terms of daylight supply. Sunlight can be reflected into the rooms via the surfaces of the facade, thus increasing the daylight yield. It should be noted that on sunny days there is a risk of glare due to the reflection of sunlight on opposite facades. Very bright or glossy and reflective surfaces can produce strong differences in luminance and the direct sunlight can be reflected into the rooms.
How do you bring sunlight into a north-facing room?
If you don't want to miss out on the light qualities of direct sunlight despite the north-facing location, then it is worthwhile to check measures in the design phase to ensure minimal sunlight during occupancy times. The following options are available to provide north-facing rooms with direct sunlight:
Skylights in various shapes (flat, domes, shed roofs, etc.)
Staggered roof and introduction of a clerestory windows
Protrusion of northern rooms to the sides and lateral capture of the southern light.
Tilting the Windows of the northern facade openings to the east or west to capture sunlight
Courtyards or atriums for a two-sided lighting and reduction of room and building depths.
Summary
Northern daylight is characterized by a large proportion of diffuse daylight, a soft, constant, and low-contrast light.
North facades receive sunlight during the off-peak hours of the summer months. This can lead to glare for a short time due to the low angle of the sun.
In general, rooms that need constant and low-contrast light or where a quiet and introverted spatial experience is wanted benefit from northern light. Examples are work and artist spaces, galleries, museums, or sacred buildings.
Due to the low solar heat input, positioning on the north façade is also suitable for rooms with high internal heat loads or where a lower room temperature is acceptable.
To avoid a gloomy impression of the room, a good supply of diffuse daylight from north-facing rooms is all the more important. The decisive factor here is the spatial geometry in relation to the size and location of the facade openings.
Do you want to know more? Here you can read about daylight from other orientations:
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This series was inspired by Amelia Lee's podcast Undercover Architect S1 Ep.2-5. I would like to thank the architectural firms and photographers who allowed me to use their work as sample projects.
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