Bullitt Center Seattle Greenest Commercial Building on Earth

In 2006 the International Living Futures Institute created the ‘Living Building Challenge’ which sets standards for buildings to not only have completely net-zero energy and water usage, but to use HALF of the energy that it takes to become a LEED platinum certified building. The ‘Living Building Challenge’ won’t certify a building until it has proven that these efficiency goals are met or surpassed for an entire year after people move in. To date, the LBC has only certified three buildings on the entire planet, all of them in the USA, and now a six-story tall, 50,000 square foot office building in downtown Seattle is vying to be the next by being entirely off the grid: The Bullitt Center.

The Bullitt Center will use a rooftop made entirely of solar panels for its energy, geothermal wells for its heat, composting toilets (remember, it’s off the grid), and a massive rain cistern for water. While it’s relatively easy in cloudy Seattle to get plenty of rainwater and treat it with a biofiltration system, getting enough sunlight to power a building of this size required rethinking every aspect of the project in detail; but the solar panels aren’t going to do all of the work; the building’s design and its occupants play important roles. To dramatically cut the energy consumption of the Bullitt Center by 77 percent as compared to a traditional building of its size, natural sunlight will account for 82 percent of all of the lighting in the building, thanks to huge windows and high ceilings that help the light get farther inside. Additionally, the building’s automated computer control system automatically opens and closes the windows based on interior temperatures, completely eliminating the need for air-conditioning.

Even with the building controlling it’s ultra-efficient heating, ventilating and air-conditioning systems, occupants are also going to have to make lifestyle changes such as using the stairs instead of the elevator and using MacBook Air laptops which use less energy than a 100-watt bulb, rather than using traditional desktop computers.

The Living Building Challenge requires a project to meet 20 specific imperatives within seven performance areas. For the Bullitt Center, meeting those imperatives will include the following:

Site: The location will support a pedestrian, bicycle, and transit-friendly lifestyle.
Water: Rainwater will be collected on the roof, stored in an underground cistern and used throughout the building.
Energy: A solar array will generate as much electricity as the building uses.
Health: The building will promote health for its occupants with inviting stairways, operable windows & features to promote walking.
Materials: The building will not contain any “Red List” hazardous materials, including PVC, cadmium, lead, mercury and hormone-mimicking substances, all of which are commonly found in building components.
Equity: Unlike most office buildings, large operable windows will offer fresh air and daylight to all the people who work in the Bullitt Center.
Beauty: Stunning architecture, an innovative photovoltaic array, a green roof and other native plantings, large structural timbers and a revitalized neighboring pocket park will help beautify the surrounding streetscape.

The most astonishing fact to us about this project is that it only cost the builders $355 per square foot; less than most residential here in Vermont cost. We can only hope that Burlington will catch up with the rest of the world someday.

The building’s most impressive features:

• Highly energy-efficient building envelope. The mostly glass building has a modeled energy-use intensity (EUI) of 16 kBtu per square foot per year. This makes it 83% more efficient than typical office buildings in Seattle. This is achieved with such features as triple-glazed, low-e, argon-filled windows, automated exterior shades, and high insulating values for non-glazed portions of the building.
• Solar-electric system. A rooftop 242-kilowatt (kW) photovoltaic (PV) system is projected to deliver 100% of the building’s electricity needs on an annual basis. Since Seattle isn’t very sunny, this net-zero-energy performance will depend on the weather each year. On a good year, the PV array should have no problem meeting that goal, but some years there is a lot less isolation than average. To get a large enough PV array on the roof to supply electricity for six floors, the PV array cantilevers out over the walls.
• Ground-source heat pump heating and cooling. Twenty six 400-foot-deep wells drilled beneath the building provide a heat source and heat sink for the building. Both heating and cooling are delivered through radiant systems. This all-electric system is projected to use only 5% of the electricity produced by the building’s PV system.
• Lighting and plug loads. Daylighting provides 90% of the building’s lighting needs. Power consumption for electric lighting and plug loads (computers and other devices that plug into outlets) is kept low in part through a unique, internal “cap-and-trade” system in which tenants have a specific energy budget. If they use less electricity than their budget, they can trade with other tenants in the building who may need more. Tenants sign a thick contract that includes penalties if their energy budgets are exceeded.
• Operable windows. Many of the large triple-glazed windows that comprise much of the wall area of the building are operable. Rather than hinging open, the German Schüco mechanisms keep the windows parallel to the wall as they open, which improves the ventilation. The mechanisms are automated but have manual override. To achieve the LBC requirement for local materials, Schüco partnered with a local glazing fabrication company to produce the units, and that company is now going to be a regional producer of high-performance curtainwall systems.
• Rainwater harvesting. The building has a 56,000-gallon cistern for storage of rainwater that is harvested on the roof. This water, after filtration and multistage treatment and polishing, can supply 100% of the building’s water needs, including drinking water, the three ounces of water used per flush in the foam-flush toilets, showers for bicycle commuters (there are showers on each floor), and landscape irrigation. (Permitting issues are still being worked out to allow the building to use only site-harvested water, but hopefully that will be resolved.) Interestingly, while Seattle is cloudy a lot of the time (225 cloudy days per year) and it rains a lot (150 days per year), the total rainfall in Seattle is quite low: only 37 inches per year on average, compared with 43 inches for Boston and 49 for New York City. The exception to the self-contained water system is the building’s sprinkler system, which the city required be on municipal water pressure.
• Composting toilets. To get the building’s water consumption low enough to satisfy it entirely with site-harvested water required composting toilets. The four foam-flush toilets on each floor (24 total) deliver waste to ten Phoenix composting units located in the basement.
• Durability. The building’s timber structure is designed for a 250-year life, and the building envelope or skin has a projected life of 50 years before it will need replacement — which can happen without affecting the structure.
• Local materials. Reflecting the Pacific Northwest’s timber resource as well as a desire to minimize embodied energy of materials, all of the structural wood for the building is local Douglas fir from forests that were certified to Forest Stewardship Council (FSC) standards. Glulam beams are produced from two-by dimension lumber. Incidentally, the Bullet Center is the largest heavy-timber building constructed in Seattle since the 1920’s.
• Safe materials. Tremendous effort was expended to avoid the use of several hundred red-list chemicals. Manufacturers whose products were used have to go through the International Living Future Institute’s Declare program or produce a Health Product Declaration to certify that red-list chemicals are not used. This feature of the Living Building Challenge is have a huge influence on product manufacturing today, leading to greener products. A number of manufacturers altered their manufacturing to comply with LBC requirements.
• Occupant comfort and daylighting. All tenants in the building will have access to daylight, either from proximity to outside walls or through glass interior partition walls. Even the stairwell is fully lit by sunshine.

As might be expected, the Bullitt Center wasn’t an inexpensive building. At $18.5 million dollars, or $355 per square foot, this is about $50 per square foot above the average for high-quality, Class-A office buildings in the region, according to the Bullitt Foundation. But it is a demonstration of pushing the envelope and proving that the environmental impacts of buildings can indeed be dramatically reduced.

Office space in the building is being leased at $28 to $30 per square foot per year, slightly higher than average for Seattle, but tenants get free electricity and water at that price — as long as they keep within their allotted limits.

The Bullitt Center is easily one of the most important commercial buildings built in North America in the past 50 years; and should be something that ALL cities build zoning laws around.