November 6, 2008

Does your LEED building measure up?

  • Once a LEED building is finished, things such as electricity and water usage must be monitored to verify expected performance levels.
    Perkins + Will


    Two years ago, the first LEED platinum project was certified in Washington state. The 12,000-square-foot office space was designed by and for Perkins + Will, a sustainable architecture firm that wanted a space to demonstrate the sustainable technologies it advocates to its clients.

    To become certified under the LEED rating system, estimates of energy and water savings need to be submitted. Now that the space has been occupied for two years the question became: How is the space performing? Is this LEED platinum project actually saving the energy and water that was predicted during the design of the space?

    Assessing whether a LEED project is performing as planned takes some work. During the first year of occupancy, adjustments are usually made to a space as the staff settle in and use it. In this case, quite a few changes were made: acoustic panels were added in the conference rooms; a meter was added to track water use; a secure bike rack was installed because the garage one experienced bike thefts; and some tweaks were made to the lighting controls that were not functioning well. Also, a food composting system was added and controls to the external west-facing sunshades were changed to allow separate room control.

    Photo courtesy of Perkins + Will
    Perkins + Will’s offices in Seattle were LEED platinum certified two years ago. The design firm found its water use has been about 3 percent above predictions, probably due to more employees biking to work and taking showers there.

    Once all the changes were made, the firm started on the task of evaluating the space. The major focus was to assess how much energy and water the space was using. Also, an ongoing effort looking at indoor air quality and occupant comfort will be completed by early 2009.

    One of the points in the LEED rating system requires metering of energy. The idea behind that point is to provide the building owner/occupant with the ability to check their actual energy and water use against the predicted use. It allows building owners and occupants the ability to know if something is not working well and using more energy than expected. Statistically, the systems in many buildings never operate as they were designed due to installation errors or poor maintenance.

    As this is a LEED platinum project, an electricity meter was specified during the original design as a requirement to easily track usage. A water meter was also added that can track usage just for the floor that Perkins + Will occupies. It is still important, though, to verify the accuracy of the meters by checking that their numbers align with energy and water bills.

    So how much electricity did the space use compared to the predictions?

    The predictions for yearly energy use in the space during the design phase were 10.8 kilowatt hours per square foot. To give this some perspective, a typical office space built to current city code would use approximately 13.8 kilowatt hours. The electricity meter in the space recorded 10.6 kilowatt hours. This tells us that all systems are working and running as designed.

    The space performed similarly on water use. It was predicted to use 35,000 gallons of water per year while a typical space this size would use 60,000 gallons. The actual water use tracked from the meter was 36,000 gallons per year. The water savings in the space demonstrate a 40 percent reduction in use over a typical space. The office has experienced an increase in the amount of bike riders during the past year, which has increased shower use significantly.

    The energy used in all 21 Perkins + Will offices, as well as air travel, is offset through the Chicago Climate Exchange.

    Chicago Climate Exchange, launched in 2003, is the world’s first and North America’s only active voluntary, legally binding integrated trading system to reduce emissions of all six major greenhouse gases with offset projects worldwide.

    Perkins + Will’s Seattle space has performed almost exactly as expected. The next challenge for the office is to look at opportunities to reduce water and energy use even further, to conduct an occupant survey, and to process results from an indoor air quality test.

    To make energy tracking even easier than reading meters, a new initiative under consideration for Perkins + Will next year is to introduce on-line tracking of electricity use across multiple offices.

    Amanda Sturgeon, AIA, LEED AP, is a senior associate in the Seattle office of Perkins + Will and is co-director of the firm’s Sustainable Design Initiative. The architecture firm has 21 offices worldwide.

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