We all know how hot it can get during these summer months. While I sit here next to a window in my cubicle, it got me thinking about proper window design. Many of us spend most of our day inside buildings that do not have efficient windows. You can definitely feel the difference when you walk into a room with windows facing south and/or west. Improper glazing can negatively affect the building’s energy consumption, appropriate levels of day lighting, and the occupants’ visual and thermal comfort.
When it comes to window design, there are several variables to consider. A few come to mind such as the current climate condition, where the building is located, the building size and type of windows, and the building’s primary function.
The orientation of the building plays a big part on how it can maximize solar access. Taking full advantage of day lighting can help reduce the need for electrical lighting as well as heating and cooling loads. One best practice on proper building orientation is with the long axis of the building oriented east-west to maximize southern exposure and northern indirect lighting which can contribute to less heat gain and glare.
The window size and placement on the building, according to the regional climate, also play a part in climate control. Colder climates perform differently than warmer climates. In colder climates, it’s best to take full advantage of the sun by placing larger windows on the south side, which can provide greater opportunity for passive solar heating. Here, the sun rises farther south of east and also sets farther south of west. In warmer climates, it’s difficult to control solar heat gain and glare when placing windows on the east and west sides of the building. The sun rises north of east and sets north of west. Therefore, windows on the east and west sides will get direct sunlight for several hours each day. This will also bring in more heat when it is not needed. One solution to help control this in the warmer climates is to provide window shades, fins and/or overhangs. However, north and south facing windows should be significantly larger to provide better daylight and views.
The type of glass also plays a part in the aesthetics, energy consumption, and glare within the building. Different types of glazing vary in their abilities to let light through and to prevent heat loss. Glazing is rated by several factors such as:
1. U factor: This is a measurement of the rate of heat transferred through the glass. The lower the U factor, the less heat that actually enters the building.
2. Solar Heat Gain Coefficient or SHGC: This is the fraction of the solar energy that is transferred through the glass of a window. In cold climates, a higher SHGC is ideal to collect heat from the sun. In warm climates, a lower SHGC is desired to block heat from the sun from entering the building.
3. Visible Transmittance or VT: This is how much light is transmitted through the glass. The higher the percentage, the more light that comes through the window.
All of these factors can be obtained by window manufacturers.
http://www.efficientwindows.org/ToolsForSchools.pdf
I work in a 50's era building that used to have very large windows, but they have since been covered with painted board to conserve energy. This is not very aesthetically pleasing. I am in hopes that with all of the advances that are being made in windows, we might be able to put back in the full windows, just in a more energy efficient model.
ReplyDeleteMelissa Bryan, Tarleton State University
Melissa,
DeleteWe have the same situation at the Dublin Junior High. I would also love to see new windows installed. I think natural lighting is great!!
In the last several years, the importance of window placement, day lighting, and occupants’ impact of such variables, has dramatically increased [as seen in literature emphasis]. I think this topic is very important due to its positive impact on a building’s energy consumption and occupants’ impact on productivity. Schools across the United States are taking notice of this topic and incorporating its impact into building design. For example, Lady Bird Johnson Middle School in Irving, Texas effectively incorporated window placement and day lighting into the building design; thereby maximizing building energy efficiency and potentially increasing student productivity. Both effective window placement and day lighting were contributing factors in the school’s designation as a net-zero educational facility.
ReplyDeleteAlso, Heschong Mahone Group (1999) conducted an extensive investigation into the relationship between day lighting and human performance in three school districts across three states, including California, Colorado, and Washington. Within the three school districts, grades 2-5 were observed while being taught under standard district conditions, participating in standardized testing measures (1997-98) for each respective state and spending a majority of their time in one designated homeroom. The authors concluded their research study with significant findings, including: a uniformly positive and highly significant correlation between the presence of day lighting and student performance in all three districts, and that day lighting, provided from skylights, distinct from all other attributes associated with windows, had a positive effect. With the vast amount of professional and research literature available on window design, educational professionals should seriously consider adopting facilities design mandates which optimize such design variables that positively enhance student’s learning environment.
H. Ortiz (Tarleton State University)
I have never considered the placement of the actual building in relation to direct sunlight until reading your post. When dealing with a new construction that needs to be taken into serious consideration when looking for a site and then planning the layout of the site. However, renovation efforts don't allow any changes in the location of a building so we have to rely on better windows instead.
ReplyDeleteI am a huge proponent of natural lighting through large single-paned windows in classrooms. In winter, those windows help bring in much needed warmth. However, as winter gives way to spring, summer and even early fall, the Texas sun can completely overpower those large windows. Through recent, extensive renovations to one of our elementary schools and our high school, all windows were replaced with glass that had a low U-factor rating. We have also instituted an energy plan that has already realized saving into the hundreds of thousands of dollars. Though there are many pieces to the energy plan, I have no doubt that those more energy efficient windows have significantly added to the cost savings and will continue to do so.
A. Stewart - Tarleton State University
The design, shape, tint, size, and placement of windows may affect both the aesthetics and energy consumption of facilities. As a former member of the planning committee for the Tarleton Recreation Center, a great deal of emphasis was placed on building and window design and the local climate. The architects designed the proper angle, and layout which included a "green" design, focusing on energy efficiency. The placement of the building (which includes lots of large glass windows) is strategically designed to accommodate for the sun setting, and geographical climate. This is paramount so that the windows are not only aesthetically pleasing but can accommodate for the scorching heat we face in Texas. Quality and placement of the windows allow for the sun to enter the building during the earlier part of the day (typically the coolest part of the day) and set at the back of the building, which has more brick and very few windows.
ReplyDeleteUnderstanding more about "green" building and sustainable design may not be in the "wheel-house" of most administrators. However I realize the importance of knowing or researching to learn more about window design and sustainable facilities.
Reggie Hall
Tarleton State U.
Tarkington Elementary School, the first campus in the Chicago Public Schools to be built to meet the green standards, designed their school to be environmentally responsible. The windows in the classroom are extra-large, provided more natural light. In addition, they installed sensors into their lighting system to automatically adjust the amount of sunlight entering into the classroom. By doing this, it maximizes the use of natural energy.
ReplyDeleteSchool systems in Louisiana also utilize natural light by the use of windows. After hurricane Katrina, they were forced to rebuild schools and made the decision to build energy-efficient schools. Langston Hughes Elementary School designed their building with minimal east and west facing glass in order to minimize the glare in the classrooms and to provide solar heat in the morning and afternoon.
S.Lewis, TSU
It is interesting to see how far school design has come. While attending K-12, we always joked that the school was actually supposed to be a prison given the lack of windows in the buildings.
ReplyDeleteLast summer, I had the opportunity to visit several schools that had recently been built. It was exciting to see that school designs have progressed since I was in K-12, in that windows were part of the design. More importantly, the windows were strategically placed to minimize expenses while magnifying natural light sources.
CAndrew - Tarleton State University
BFaulknerTSU
ReplyDeleteSince windows can now be engineered to provide energy savings, I would like to particularly address the aesthetics of having windows in an educational facility. Corporate executives have the most status when they have the most windows or the best view, whereas cubicals and basement offices are considered harsh and unwelcoming. Everyone enjoys a window and the view that it provides, especially students. People who occupy a room without a window usually complain and, unarguably, we don't need to give students or teachers, for that matter, anything else for which to complain. Generally, windows in the classroom provide spontaneous teachable moments - the weather, the geese flying south for the winter, even the evolution of energy considerations for educational facilities can all be incorporated into a classroom discussion.
Thank you for the excellent resource! My school is preparing for a bond election to construct a new elementary school. While we have an architect whom has provided a lovely floorplan, it is the small (but important) details such as this we must also take into account.
ReplyDeleteLindsay Morgan, TSU
I had never really considered the impact of window design on the classroom climate but this is so true. I too have large windows in my office and during this blistering summer sun it becomes very hot. When I was in a school district in Colorado they had large windows but it was very nice in the winter when the sun would shine it. Not only did it impact the climate of the room but I also believe that the natural light is a great resource for attitude and energy level in the classroom. I know that I personally am in a much better mood and have more energy when I can see some natural sun light shining in the room.
ReplyDeleteLeslie Mills TSU
The Dublin Middle School ,which is almost 100 years old, use to have windows all around the building. Now most of them are covered besides one in each classroom. We have two fairly new school facilities and it is amazing to see the differences in the construction of each building, even the windows.
ReplyDeleteI thought this post was very interesting. My campus was constructed primarily in the 1960s with a few additions in the 70s and 80s, and none of these building considerations were taken into account. Only 3 (out of more than 50) classrooms in the entire building have windows of any sort. We rely entirely on flourescent lighting in the classrooms, library, cafeteria, and hallways. In addition to the environmental aspect of this issue, I think it is detrimental to the students' development to have no natural light in the building.
ReplyDeleteElizabeth Garcia - Tarleton State University
Its very interesting to me that something like window design has such a large effect on school facility temperature. It makes sense when you think about it, but I can see how it might be a factor overlooked when you are trying to get school up soon for high population growth districts, especially in the past.
ReplyDeleteM Nelson (TSU)
Natural light is wonderful in an academic or working environment. I work in the basement portion of my building and there are no windows, and it is somewhat disorienting when I emerge - especially when the weather changes. It would be so nice to have natural light!
ReplyDeleteThe building itself is only about 6 years old,and is very green, there are many windows, but they are coated, and there are automatic shades that unfurl during times when the sun is intense. Besides the new technologies in coatings and window design, shades like these are also a good option. It is nice that they can be programmed for optimal use and then they just work on their own. I suspect that along with the window coatings and the technology built into the windows that the shades help save energy.
Jerry Racioppi - Tarleton State University
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