Living up to Expectations

By KJ Fields

Although green buildings are designed to conserve resources and provide greater efficiencies, initial projections are not a guarantee of day-to-day performance. To find out if Portland State University's Stephen Epler Hall is achieving its goals, master's student Cathy Turner conducted a study of the building's first year of operations. The study reinforced the importance of post-occupancy evaluations and uncovered some encouraging results.

Epler Hall is a $10 million, six-story facility that houses ground floor classrooms and 130 studio apartments. The LEED-silver certified project became the first mixed-use building in Portland to receive LEED certification.

The cost of the residence hall's green building features totals nearly $400,000. Offsetting credits from an Oregon Business Energy Tax Credit, a grant from the City of Portland's Green Investment Fund and reduction in the city of Portland Systems Development fee equated to $136,000, making the net investment in green building features $290,000.

In its first year, the building realized a 20 percent increase in energy savings over design modeling estimates, which is 50 percent better than buildings constructed to current code.

The design team combined passive design measures and efficient systems to enhance energy conservation. The building is oriented to take advantage of the climate and site conditions, and employs natural ventilation, sun shades, and low-e, argon-filled operable windows to cool the building. These measures eliminated the need for air conditioning. A heat recovery system, premium efficiency boilers, high insulation and efficient lighting also lower energy use.

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"In the studio apartments, excess heat from lights and a computer monitor is enough to warm the rooms without supplemental heat for most of the year," said Terry Miller, G/Rated Green Building Program Coordinator for the City of Portland Office of Sustainable Development.

Epler Hall's water use was 11 percent higher than anticipated for the total building and 17 percent higher for the residential area, but residential use still outperformed code by 25 percent.

Most of the water savings were generated by low-flow plumbing fixtures. A rainwater harvesting system captures and filters site water for landscape irrigation and reuse in ground floor toilets. During the study timeframe, equipment problems and meter incompatibility negatively affected the system's performance. In addition, building commissioning was not completed until partway through the year. With the systems properly adjusted, additional savings may be possible in future years.

Michele Crim was PSU's Sustainability Coordinator for three years before becoming the Sustainable City Government Initiative Coordinator at the city's Office of Sustainable Development. She said the true value of the rainwater system is not financially based.

"As a visible demonstration project, the system is a living laboratory for students and faculty and it informs broader decisions in the community," said Crim. "With all the exposure it's received, it's paid for itself ten-fold."

While the study found areas for improvement as well as some pleasant surprises, it verified that the green building investment was a wise choice. Based on a 25-year span, the present value of annual savings from conservation features will generate a return on investment over $700,000 and an average return of approximately 14 percent.

Key Players:

Contactor: Walsh Construction Co.
Architect: Mithun
Mechanical and Electrical Engineers: Interface Engineering
Landscape Architect: ATLAS Landscape Architecture
Green Building Consulting: Green Building Services