How Sunshades Combine a Visual Accessory With the Ability to Improve Energy Efficiency
As architects look to help buildings be a solution on global climate change, they shouldn’t forget the energy efficiency boost provided by the humble sunshade.
Centuries later, we’re still in awe of the design elements of the pagoda. These tower-like, multistory, solid or hollow structures found in East and Southeast Asia were made of stone, brick, or wood and built to serve as temples. Looking at these architectural relics today, one can’t help but wonder if the climate influenced the design or if the upcurved overhangs were simply beautiful accent pieces. Perhaps the answer is both. The intricate overhangs were not only stunning but also provided shade from the sun’s heat and glare.
Modern-day shading devices as part of a building’s design have the power to balance the positives of daylighting―including the benefits of natural light to occupants, helping to reduce glare, and savings on lighting energy use―with potential heat gains and losses. Common shading devices include exterior overhangs and sunshades, interior blinds and screens, and roller shades.
Exterior overhangs and sunshades are typically used to block the summer sun, which is higher in the sky, while allowing sunlight to enter the building in winter, when the sun is at a lower angle. Overhangs are fixed elements on the exterior of the building. Sunshades serve a similar function as overhangs but generally refer to metal louvers attached above or in front of a window. The brackets, outriggers, and louvers come in many styles to accommodate different aesthetic and shading goals.
Sunshades, in particular, can make buildings more resilient to the heat and sun, mitigate solar impact, and reduce the need for excessive indoor climate control. When you think about the fact that buildings generate nearly 40% of annual carbon dioxide emissions, according to Architecture 2030, it is imperative to think about climate impact throughout the whole building. Energy savings alone from reduced electric lighting can directly decrease building cooling energy usage by an additional 10% to 20% based on Whole Building Design Guide estimates.
“Sunshades are applicable to almost every type of building, including commercial offices, airports, schools, government institutions, or any that could benefit from relief of solar heat gain,” said Pat Boucher, regional sales manager at Oldcastle BuildingEnvelope.
Incorporating sunshades into a project gives owners the ability to replace electric lighting with daylighting for much of the day, which not only cuts down on direct energy use, but also produces less heat. This can be significant in buildings with large cooling loads.
Still, adaptability is paramount if you want to achieve climate efficacy with your sunshade solutions. The following must be taken into consideration:
- The building’s orientation
- The side of the building where the sunshade will be installed
- The peak times of day when the sun is most radiant
- An understanding of the sun’s relative position at different times of the year
Each of these factors will help to determine the type of solution needed. For example, the Solar Eclipse Single Blade Sunshade can be applied horizontally or vertically—horizontal projections work best on south-facing facades, as they block direct sun at high angles, while vertical projections work best on east- and west-facing facades, blocking the sun when it is lower in the sky.
“Vertical sunshades are the most effective for east and west elevations where you have low sun angles that make shading difficult,” Boucher explained. “Using shades that are adjustable can have an even greater effectiveness at these elevations, and as an architectural feature they can help express the vertical lines of a building.”
Designers must carefully balance daylighting goals with building code requirements, energy performance goals, and glare control. Pairing sunshades with glazing solutions, such as a storefront or curtain wall, can further maximize energy efficiency to help accelerate the decarbonization of the built environment. An integrated design approach that considers daylighting in tandem with energy performance and other project goals can help ensure a successful outcome.
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