Previous posts: Part I, Part II
Back to STACEY and, this time, with DAYLIGHTING & VIEWS. Daylighting is a very important yet neglected aspect of buildings. In addition to its benefits for energy-saving, it has huge psychological and productivity benefits for a building’s occupants as well.
As for productivity, studies have shown that daylight can have a substantial effect on the performance and productivity of the occupants of the building. A study performed by CEC PIER says the following:
In Seattle Washington and Fort Collins Colorado, where end-of-year test scores were used as the outcome variable, students in classrooms with the most daylighting were found to have 7% to 18% higher scores than those with the least. In San Juan Capistrano, California, where the study was able to examine the improvement between fall and spring test scores, we found that students with the most daylighting in their classrooms progressed 20% faster on math tests and 26% faster on reading tests in one year than in those with the least.
The same study also concluded that having better views can significantly increase productivity:
Workers in the Call Center were found to process calls 6% to 12% faster when they had the best possible view versus those with no view. Office workers were found to perform 10% to 25% better on tests of mental function and memory recall when they had the best possible view versus those with no view. Furthermore, office worker self reports of better health conditions were strongly associated with better views. Those workers in the Desktop study with the best views were the least likely to report negative health symptoms. Reports of increased fatigue were most strongly associated with a lack of view.
Furthermore, adequate daylighting can produce enormous energy savings over the years. When you have enough daylight coming through your window, you don’t need to turn on the lights during the day. Some studies have shown that having better daylighting in a building’s spaces can decrease energy consumption by 45%.
So yes, it is an excellent thing to have, and it benefits everyone – except architects who, once more, seem to be making everyone’s live a bit harder. I seem to remember that I never turned off the lights in my university dorm room, and that was in the UAE – a country that has one of the highest hours of full-sun per day.
Designing a building without taking daylight into consideration from the very beginning and then trying to somehow compensate for it later is just fixing an architect’s mistake. Such oversights would not happen if, instead of the architect having complete authority over the “form” and shape of the building, an integrative design process (IDP) determined them along with daylighting and views at the same time.
Proudly, Stacey had such a process. The first step was to orient the building to give better year-round daylighting results, as well as minimizing the solar heat gain. That achieved, it was then time for some in-depth daylighting simulations using some cool software – IES <Virtual Environment> – to determine the type, size, and location of these windows so that they met LEED’s recommended illumination levels.
I remember running many simulations for different variations of windows until we had the optimum daylighting that met the LEED benchmark and that also minimized solar gain. The variables were VLT (Visible Light Transmittance), SHGC (Solar Heat Gain Coefficient), u-values, size of windows, double glazed or triple glazed, their location and height from the ground. Some of these variables were conflicting. For example, higher windows meant deeper light penetration but higher ceilings meant that more energy would be required to air-condition the spaces.
As a reminder, this table shows the baseline and proposed constructions for windows:
And here’s an image of the daylight distribution for one of the apartments (in lux) after the window type and their locations had been optimized.
This is a comparison between south-facing living rooms and north-facing living rooms.
Speaking of daylight and windows, you might be wondering why the south facade doesn’t have any shading devices on it. Many people do. There’s a general expectation for buildings to have some sort of “architectural solution” to the problem of solar gain on windows, regardless of whether it actually is a problem or not. I have seen shading devices shading walls and columns so there seems to be a bit of confusion about what shading devices are for in the first place. Unless a study or simulation is performed, it’s not possible to know if shading devices are necessary or not, and if they are, whether they are actually doing anything to reduce solar gain or just look like they might be.
As far as I know, shading devices are supposed to decrease the solar gain from sun hitting the windows, usually around midday. However, Stacey has such good windows in terms of their thermal properties (u-value, SHGC) and their ability to allow daylight through them (VLT), that shading devices would would have little effect. If the performance of Stacey’s windows hadn’t been as good, then it would have been necessary to have some sort of shading device on the south facade.
That’s all I have to say about Stacey’s Daylighting & Views. The thing to remember is that windows only need to be shaded if their performance is not very good. Supporting evidence is provided by this Master’s thesis. This is an example of a silly shading device. (I’m sure the sun hits the upper part of the building as well.)
This is so informative, I thank you so much for all the details and explanations given. I experienced the difference in considering the day-lighting in design when we moved 2 months ago. It makes a huge difference in the mood and productivity, and we don’t have to turn on the lights until after 5 pm, compared to our previous residence where we had to turn them on all day long. It does make a big difference.
The silliest thing I’ve ever heard is this shading device for capital gate, I mean we all no this exists only to complete ‘the look’. Why make fun of yourselves by trying to hide that? I seriously thought that it might’ve had a structural purpose, but now after I’ve seen the structural design, it doesn’t contribute to it at all.