What does sustainability mean to you?

Linked Student

What Does it Mean?

To me, sustainability means having good performance in multiple aspects, including energy consumption, daylight availability, thermal comfort, air quality, and so on. Usually, sustainable buildings meet some criteria and receive certifications to indicate that they are sustainable.

There are a lot of green building rating systems: LEED, WELL, Fitwel, Green Globes, BREEAM, DGNB, Green Star, BEAM PLUS, and so on.

Take LEED as an example; it has nine categories:

  • Location & Transportation
  • Sustainable Sites
  • Water Efficiency
  • Energy & Atmosphere
  • Material & Resources
  • Indoor Environmental Quality
  • Innovation
  • Regional Priority
  • Integrative Process

All of them are important indicators of sustainability, although it would be hard for most buildings to cover all of them.

What Inspirational Examples Can We Learn From?

Santa Monica City Services Building

Curtain wall system

The Santa Monica City Services Building is a commercial building that meets the Living Building Challenge criteria, which is currently the most rigorous criterion for sustainability. The building has a complicated glass curtain wall system. The curtain wall panels have variable densities of frit patterns sandwiched between the two glazing panes to reduce solar heat gain. There are operable windows and passive shades. The façade system uses passive techniques to maximize daylighting and natural ventilation and reduce energy use. The manually controlled facade system improves both heating and cooling performance while minimizing operation and maintenance costs. The building has a low EUI target of 21 kBtu/ft2. The curtain wall with patterns sandwiched between glass panes also reduces the available daylight compared to glazing without patterns.


Frit patterns on the glazed curtain wall


Bullitt Center

Kinetic shading system

The Bullitt Center in Seattle is known as one of the greenest commercial buildings in the world. Its EUI is only 16 kBtu/ft2. The current Seattle Energy Code’s EUI requirement for an office building is 51 kBtu/ft2. A typical office building in Seattle usually has 72 kBtu/ft2 of EUI. The shading system of the curtain wall facade is an essential factor for achieving a low EUI. The Bullitt Center has an adaptive curtainwall façade. The apertures have operable interior rolling shades and exterior louver blinds to shield glare and unwanted solar heat gain. The interior blinds are used to prevent glare, while the exterior shades are used to block the heat. The windows are designed not to influence the exterior shades when open. They are also automated to improve passive ventilation. Occupants could only open or close the windows within a certain range of temperatures. Once the outdoor air has reached an excessively hot or cold temperature, the façade system automatically switches to the most energy-efficient mode to maintain the interior environmental quality. Both windows and blinds operate themselves to adapt to changing climate conditions.

Nevertheless, located in a rainy city, the Bullitt Center has a large, extended roof with integrated PV panels to generate sufficient solar energy. The roof itself creates shade on the facade areas of the upper floors. This feature may not be applicable to many office buildings in dense urban areas. The three separate control systems of the façade are also complex.


Three layers of windows and shades