Presentation + Performance: Creating More Than Eye-Catching Building Façades

Architectural Products- FINAL

Presentation + Performance: Creating More Than Eye-Catching Building Façades

Effectively combine windows and solar shades to achieve design intent.

In this age of productivity, efficient, effective and aesthetically pleasing building product solutions are essential to the success of any architectural design. Understanding how to combine glazing and solar shading solutions noticeably impacts a building façade’s aesthetic and overall performance, and their specification is one of many important decisions in achieving the design intent.

Specifying glazing and shading regularlyoccursduring separate points in the project timeline. As a result, shading attachmentsaretypically selected solely for their appearance, rather than performance. While glazing has always beenan integral part of the façade, adding high-performance shading attachments optimizesinterior and exterior aesthetics, and performance characteristics. Energy efficiency, glare control, view through and increased occupant comfort are among the notable points in this discussion.

Weighing Pros and Cons

Marked by an increased focus on design intent, architects and building owners must meticulously analyzethe benefits and drawbacks of different glazing and shading combinations.Solar shading manufacturers have noticed a trend towardspecifying high transparency glazing in order to draw a greater connection between the inside and outside of a building.

A study by HeschongMahone Group, for example, showed that occupants with views of nature were six to 12 percent more productive than occupants without such views1. Companies including Google, Dow Chemical and many others have responded to the trend within the last yearby maintaining beautiful natural areas on their corporate campuses that canbe easily seen from inside.

In buildings where shading solutions vary by occupant, such as Class A office space ormultifamily applications,the exterior may read in multiple colors based on individual tenants’ shade color selection, which has an effect on the exterior appearance represented in the glass. White shades may read a bit green behind clear glass, while black or darker shades are less visible sincethe reflected properties of clear glass are dark due to the cavity of the space behind it. In fact, even consistent light-colored shades behind clear glass can create a ‘snaggletooth’ lookthat is visually distracting when they are lowered to different levels during the day. Therefore, dark shades are often used for continuity with the building’s original design intent.

Another key issue of design selection is privacy. Some architects and designers have turned to reflective glazing, which solves this issue in the daytime, and brings uniformity to the building exterior. This is a more permanent decision, however, and some buildings may still require manual privacy fabric attachments to control privacy at night, when reflective glazing has no effect.

White shades, for example, offer excellent privacy, but may cause retail spaces to appear closed because of a lack of connection to the interior. Dark-colored fabrics, which provide great view through from the interior while controlling glare, are often combined with high transparency glazing to increase privacy during business hours – when the dominant light source is the sun. However, each situation is unique given building orientation, exterior lighting levels, window-to-wall ratio and many other factors.

Where to install shading in relationship to glazing is another critical decision that impacts both aesthetics and performance. In Europe, there is an obvious trend toward using solar shades on the exterior, while interior installations are more common in the U.S. due to ease-of-installation and the option for manual control.

In the U.S., glazingwill act as the first line of defense to reflect, absorb and transmit solar energy to meet building code requirements. Based on the reduction of visible light from the glazing,transparency levels in the shading fabrics can be specified for better view through, to control heat gain and glare, energyefficiency, or other factors related to the design intent.Light colored fabrics with low openness provide the best thermal performance, while dark shades with high openness offer the best glare control and view through. However, new advanced technologies such as KOOLBLACK®,which maintains the visibility and glare control benefits of dark fabric while enhancing energy reflection comparable with light fabric, can also help meet a building’s aesthetic needs.

Exterior shading applications frequently seen in Europe are the first to reflect, absorb and transmit solar heat, allowing for specification ofless expensive, higher transmission glass without sacrificing performance.High-transmission, triple-unit glazing specifically designed for colder climatesmakes it easier forsolar energy to enter a building and harder for it to escape using passive solar heating. This energy efficiency benefit is magnified when combined with a low-emissivity (low-E) coating. Again, there will almost always be trade-offs between aesthetic and performance characteristics to consider.

The Future of Code Compliance for Shading Attachments

With an understanding of the impacts of shading attachments in the building envelope, architects can respond to critical design questions fromthe interior designer, lighting consultant, HVAC engineer, building owner and othersto ensure the finished building meets the design intent.That responsibility, however, raises a question about how to quantify the performance of all products – including shading attachments – in the building envelope.

Led by the Department of Energy and the Attachments Energy Rating Council (AERC), the industry is taking a closer look at how glass and shades impact overall building performance. Ongoing conversations about creating a numerical evaluation on system performance with shading attachments will be important moving forward.Because glass and shades are not always specified concurrently, however, a gap still exists between understanding aesthetics and performance of glazing in conjunction with those of the shade.

Better feedback from building owners and technologically advanced tools that quantify performance impacts are closing that gap. For architects, recognizing that glazing and shading solutions are complementary pieces workingin unison for a well-balanced building envelopeis an integral part of how a building will look and perform while keeping with their intent of design.

Colin Blackford is the Innovation Manager for Mermet USA.

1Heschong, lisa. HeschongMahone Group. “Windows and Offices: A Study of Office Worker Performance and the Indoor Environment.” California Energy commission: Pacific Gas and Electric company. Fair Oaks, California. 2003c.