Shading Devices
Lechner, Heating, Cooling and Lighting, pg. 239
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I would say depends on the purpose of fins. If it is aesthetic and style, you can be Frank Gehry about them. But, if the purpose of them as protection of solar exposure, I would go with Horizontal for South, and Vertical for East and West. Also, you might need to consider orientation of fins relative to orientation of building. For north, I would not use fins as a mean of protection for solar exposure.
Cheers,
A
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North window: no shading typically needed, but if you REALLY didn’t want early morning summertime direct sun, then vertical fins would suffice (the sun rises in the east-northeast and sets in the west-southwest in June)
East/West windows: I see your confusion. Both books are correct. Either vertical fins (because the afternoon sun is in the west southwest and vertical fins on the west will shade light coming from the south), or horizontal fins provided they are spaced close together and held outboard of the window (because afternoon sun is, for most of the afternoon, above the horizon line, but not high enough to be addressed by a single shading element at the top of the window because that element would be need to be extended too far from the building to be practical.) Trees work too, especially for the first and second floor windows.
South window: You already know this one. In cold and mixed climates, a single over-window eyebrow to shade from high summertime noon sun, and allow in low wintertime noon sun. This same principle works for horizontal fins, but they don’t have to be exceedingly close together on the south.
If you can't get yourself to mentally envision the solar geometry, these concepts will feel intuitive and you won’t have to rely on memorization.
– Michael Ermann, Amber Book
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I prefer vertical fins to horizontal fins because it is easy for dirt to accumulate on horizontal fins which require more cleaning.
No shading devices are needed for north windows, and it is ideal to place rooms require natural light on the north side of a building, such as a sample room of an architect’s office, or a chemical or biological lab.
Gang Chen, Author, Architect, LEED AP BD+C (GreenExamEducation.com)
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It's understood by most that shading would not be required at the north. However, in MEEB, which is one of the primary listed sources it specifically says in chp 6, 'northern windows often also need shading devices, contrary to the myth that the north facade never receives direct beam radiation.' It then goes on to say, 'for shading on the north side (at early morning and near sunset) vertical fins are most effective. It would be great if someone from NCARB could speak to this, as many of the other listed sources say not to provide any northern shading at all.
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