This post is the last in the series about the four orientations. Previously, we talked about the popular south orientation, the morning light from the east and the constant north light. Now we turn our attention to the last hours of daylight and look at how the light changes, how we experience it and how we can integrate it into our built environment.
Light from the west is the sunlight of the setting sun. The initially intense, shimmering midday light changes to a saturated, glowing red evening light as the afternoon progresses. The shadows become longer and softer until the sun disappears behind the horizon and the light is only visible across the dome of the sky.
The light qualities of westerly light are similar in many respects to light from the east, as the sun's path is mirrored at solar noon. Light from the east or west is very variable, whether in terms of intensity, light color or the position of the sun and the resulting angle of incidence of the sunlight.
Which rooms benefit from a west-facing position?
Areas where we enjoy the sun and the associated warmth, such as outdoor seating areas, terraces and balconies, are therefore particularly suitable for a west-facing orientation. Rooms where we enjoy the evening hours, such as living and dining areas or restaurants, can also benefit from the late evening sun.
The irregularly grown trees on the plot determine the shape of the new building and are also a defining element for the spatial experience. The permeable façade on both sides and large areas of glazing blur the boundary between inside and outside. The trees offer protection from the warm afternoon sun on the west-facing glass façade. In combination with the sunlight, they create a dynamic interplay of light and shadow that extends across the terrace into the interior and reinforces the connection to the outside space.
Arsenal Café by 3andwich Design in Hanhonggou Village, Shanxi Province (CN) 36° latitude, Photos: Jin Weiqi, Plans: 3andwich Design
Bedrooms in retirement homes or bedrooms of the older generation are also well located when facing the evening sun. With age, our biorhythm shifts and the circadian rhythm shortens. Among other things, this is reflected in lighter sleep, difficulty sleeping through the night and getting up earlier. Sufficient daylight during the day and in the evening can help to regulate the internal clock and delay bedtime, which in turn can lead to better sleep.¹
What needs to be considered when planning rooms on the west facade?
Sunlight brings a lot of radiant heat with it, especially at the beginning of the afternoon. Due to the increase in ambient temperatures during the course of the day, we also find the afternoon sun particularly warm and intense. Particular attention must be paid to thermal management in rooms on the west and east façades. This is because it is these orientations that are particularly exposed to overheating.
To manage the heat input, a lot can be done with the choice of window glass. Thermal insulation and insulating glass make it possible to significantly minimize heat input and loss without limiting light transmission and light quality too much.
Special glasses with integrated louvres or prisms enable targeted light control of daylight to direct the light into the interior via the ceiling and at the same time avoid glare. Light-diffusing inserts Glasses can be used for diffuse light distribution and where no view in or out is desired.
Which shading elements provide protection from the intense afternoon sun?
As with east-facing façades, effective shading is difficult due to the low position of the sun. Towards evening, direct sunlight hits the façade almost horizontally and penetrates deep into our rooms. Vertical glare protection, whether combined with external solar shading or as a separate internal element, is essential. The position and angle of incidence varies greatly depending on the time of year; in summer the sun sets in the north-west, in winter south of due west. Due to this variability with the time of year and day, adjustable and mobile shading elements are also the most efficient solution here. As with east-facing facades, there is a wide range of shading systems available, such as fabric and foil roller blinds, slat blinds, awnings, etc.
Vertical blinds are often used to shade the low sun, but can severely restrict the view. It is worth choosing a dark color for transparent sun blinds. It may seem counter-intuitive, but the darker the surface, the better the view. The bright landscape in the background becomes more visible if there is no high luminance on the textile or fabric that competes with the background.
Dark vertical blinds provide a clearer view than their light-colored counterparts. Both images are product images from Bandalux, O-box. Source: archdaily.com / Bandalux
Greenery in the surrounding area or in front of balconies and passerelles is also suitable for shading the low sun. The moving shadow patterns created by the incident light with the moving foliage form a very special quality of light.
As plants generally develop towards the light and want to capture as much daylight as possible, they form an almost closed surface on the outside, making them an effective shading method in the warmer months. If deciduous plants are used, solar energy can be used in the cold months. However, the shading provided by deciduous trees in winter should not be neglected, as a tree still provides up to 50% shade through its branches.
An alternative to outdoor planting is potted plants on front balconies and passerelles or vertical facade greening. These are also suitable for tall buildings, but the effect remains: The planting prevents the parts of the building from heating up excessively and, in combination with evaporation, creates a cooler microclimate.
The Sun Path House is entirely dedicated to the sun and its course; it is a spatial diagram of the sun's position. The main supporting structure traces the course of the sun on the longest day of the year, structures the use of the space and serves as a sun catcher. The snail shape allows the sun to be experienced in its various positions and qualities. There is an exposed solarium on the roof, the bedroom on the first floor is protected by the surrounding climbing plants. At ground level there is a covered seating area, which invites you to enjoy the last rays of sunshine in the evening.
Sun Path House by Studio Christian Wassmann in Miami Beach (USA) 26° latitude. Photos: Lukas Wassmann
Summary
Sunlight from the west is the light of the setting sun. It changes from the intense midday sun to a glowing red evening light.
Rooms where we spend most of our time in the evening and where we want to enjoy the warmth of the sun benefit from orientation to the west. Examples include outdoor spaces such as terraces and balconies, living and dining rooms, restaurants and the bedrooms of older people.
East and west-facing facades are most exposed to overheating. Some of this can be mitigated by the choice of window glass. External sun protection is nevertheless recommended. If solar heat gain is desired in winter, internal glare protection should also be planned.
Due to the low position of the sun, vertical shading elements are required. The position of the rising sun varies greatly depending on the time of year. For this reason, the shading elements should be adjustable.
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 have provided me with the use of their work as sample projects.
Quellen
1/ Flores-Villa L, Unwin J, Raynham P. Assessing the impact of daylight exposure on sleep quality of people over 65 years old. Building Services Engineering Research and Technology. 2020;41(2):183-192. doi:10.1177/0143624419899522
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