Is the Bullitt Center the World's Greenest Building?

The Bullitt Center in Seattle has been called the greenest commercial building in the world. It is also the biggest building ever built to the Living Building Challenge, the toughest green building certification in the world. To understand the building, designed by Miller Hull Architects, you really need to understand the challenge first.

lbc© Living Building Challenge
The LBC is described as:

...a cohesive standard, pulling together the most progressive thinking from the worlds of architecture, engineering, planning, landscape design and policy. It challenges us to ask the question: What if every single act of design and construction made the world a better place? What if every intervention resulted in greater biodiversity; increased soil health; additional outlets for beauty and personal expression; a deeper understanding of climate, culture and place; a realignment of our food and transportation systems; and a more profound sense of what it means to be a citizen of a planet where resources and opportunities are provided fairly and equitably?

Indeed, as they put it, a tall order. (See the 20 imperatives here)

More precisely, a building built to the standard must, among other things:

  • contribute to the creation of walkable, pedestrian communities.
  • meet 100% of its water needs through captured precipitation and recycling, without the use of chemicals.
  • 100% of the project’s energy needs must be supplied by on-site renewable energy on a net annual basis.
  • Every occupiable space must have operable windows, fresh air and daylight.
  • Contain none of a long Red List of chemicals, many of which are common building materials
  • .

water system© Bullitt Center

Water Supply

In fact, it isn't even legal to do some of the things you need to do for the Living Building Challenge certification. You are supposed to meet water needs from rainwater capture, but that's not allowed for health reasons, so the building is being connected to the City water supply until it can prove that its collected water is safe. Then the Federal government insists that all surface or collected water be chlorinated, but chlorine is prohibited on the red list of chemicals. It might be on city water for quite some time until they figure this all out. More on the water.

composter© Bullitt Center/ John Stamets

Composting toilets

Then at the other end, there are composting toilets; these are not usually used in six story buildings and needed special approvals. The toilets are marine type foam toilets that use almost no water, connected to 10 big composting units in the basement. More on the toilets.

wood© Bullitt Center/ John Stamets

FSC Certified Glulam Wood

The upper floors of the Bullitt Center are built of heavy timber construction using glue-laminated wood. They explain the benefits:

Glulams make efficient use of wood by bonding smaller pieces together to form larger components. This creates a strong, dimensionally stable and consistent product with the ability to span great distances. Using glulam timbers allows for a larger final product than using dimensional lumber, and they can be produced from lower grades of timber. During the fabrication of a glulam timber, there is only a 3% material waste.

rooftop© Bullitt Center


The Bullitt Center needs to generate as much energy as it uses to comply with the Living Building Challenge, so it is topped off with a giant solar array that is bigger than the building's footprint. It is tied into the grid but is projected to be electricity neutral, using a third of the energy of normal buildings. The building is heated using ground source heat pumps. Nina Smith-Gardiner explains, and notably does not use the word geothermal:

A heat pump employs the compression-refrigeration cycle common to both refrigerators and window air conditioning units. The heat pump is a remarkable system, using relatively little electric energy, consumed mostly to run a compressor, to transfer (or exchange) heat from one place to another with amazing efficiency.


The Bullitt Center is designed to last 250 years. We will report back on whether it makes it or not.

There's lots more: great windows that open, high ceilings for lots of natural light, sort of greener concrete, careful choice of materials, bike racks instead of parking spaces. Is it the greenest building in the world? There is no question that the Living Building Challenge is the toughest standard in the world. Since a building has to be operating for a minimum of 12 months to qualify, we won't know for sure for a while. But it's hard to find anything to complain about.

More at the Bullitt Center.

Is the Bullitt Center the World's Greenest Building?
It's hard to comply with the Living Building Challenge certification system. In some cases, it's not even legal.

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