Improving High-Performance Facades Through Post-Occupancy Evaluation

POEs are essential to ensuring building facades are functioning as intended and advancing future design
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When the team measured the single-glazed balcony doors, they were also found to be performing at their SHGC published value of 0.82, but in actually studying the doors in comparison to the windows, the design team realized a discrepancy between the thermal performance levels.

“After our POE measurements, we made inquiries and found that using high-performance double glazing in exterior doors is an available, custom option with extra expense. We now know to consider this and build in the cost on future projects when called for,” relates Hendricks.

Trammell Crow was very supportive of Kirksy’s efforts to study the building post-construction because it allowed the company to relay valuable information during its sale to Conoco Phillips. “They were happy to report that the building was working as designed,” Hendricks says.

Looking at another noteworthy POE study, HGA revisited its design for the Los Angeles Harbor College Science Complex, a three-story, 73,767-square-foot complex using approximately 43 percent less energy than baseline models and producing about 26 percent of its own electricity from solar panels.

The high-performance LEED Platinum design features integrated photovoltaic panels connected to the campus PV systems, occupancy-sensor lighting, extensive exterior shading, natural ventilation, abundant daylight, integrated building systems that respond to weather conditions, and an energy-recovery system that converts exhaust air into energy.

HGA’s POE evaluated the project’s performance in terms of general satisfaction, thermal comfort, acoustical quality, air quality, and lighting. Based on positive user feedback, HGA is using this project as a catalyst for further projects, specifically in the higher education realm.

“We are using takeaways from this project for two higher-education science buildings in California, in addition to an office project. In these new projects, the team is really enforcing a uniform distribution of lighting in the design so every surface in the room has an even amount of light, avoiding dark spots within the space,” reports Thibaudeau.

For another project, Intermountain Healthcare brought in Building Envelope Commissioning (BECx) expertise for its Utah Valley Clinic in Provo, Utah, to both assist with the design and construction of the building enclosure and to ensure, post-occupancy, that the envelope systems are designed, installed, and perform according to the owner’s project requirements.

Photos courtesy of HDR

At the Intermountain Healthcare Utah Valley Clinic in Provo, Utah, a building energy commissioner was brought in to ensure that the building envelope was performing as designed.

“We completed site reviews, witnessing of testing to confirm the performance has been achieved, as well as assisting with some one-off details on-site during the construction phase,” Vinci explains.

“Including a BECx as an integral part of the project was instrumental, as it was a critical process in achieving the project’s high-performance requirements as well as playing a key role in increasing the durability of the envelope while reducing risks of future envelope-performance issues,” he adds.

Why Aren’t POEs Standard Practice?

While the benefits of POEs are well-established and interest is growing, there are a number of reasons why building owners are hesitant to invest in them.

“The problem with POEs outside of a comprehensive commissioning process is the high potential for unpleasant surprises at the tail end of the building process, when corrective remediation is challenging and costly,” Patterson says. “In fact, one of the predominant reasons that a POE is often not conducted is that building owners don’t really want to know how the facade is performing.”

He notes that this is especially the case with investment properties where the owner just wants to claim a high-performance facade and “not muddy the marketing waters with reality.” Unfortunately, Patterson says that this kind of greenwashing is a common practice in the building industry, and substandard performance, resulting in excessive energy consumption, is paid for by the tenant so the owner has no motivation to make any changes.

Although owner-occupied buildings tend to present a more favorable scenario with a greater focus on data-verified performance, there are many cases where they prefer not to survey occupants out of concern for what they will say.

Furthermore, Thibaudeau points out that performing on-site evaluations and ongoing energy monitoring takes time and requires planning and budgeting. Oftentimes, such services are not included in the initial building project and are therefore an added cost that owners are typically not interested in paying.

While some owners will see value in POEs, they may not be willing to invest in external evaluation and may attempt to implement some form of POE within their own organization. However, Jauregui explains that the POE is only useful if the information can then be leveraged in a valuable way. “If there is nobody invested in processing and sharing this data internally or externally, there may be little motivation to collect it in the first place,” she adds.

Addressing the architect’s perspective in a Post-Occupancy Evaluation Survey Report where 29 members of the Architect & Design Sustainable Design Leaders network were surveyed, Julie Hiromoto, AIA, LEED AP BD+C, then with SOM and currently the director of HKS’s New York office, lists a number of reasons why design firms might not conduct a POE:

  • The time and cost required to produce meaningful results
  • Designer and client liability concerns
  • Client privacy concerns, such as disclosing energy performance data
  • Lack of client demand or interest and challenges communicating value to the client
  • Lack of timely responses from the client/user
  • Client desire to control or limit employee feedback
  • Limited site access
  • Unsuitability for certain program types such as retail
  • Timing of the POE since this typically occurs after project closeout
  • Lower priority of non-billable or research tasks
  • Defining scope and aligning expectations of what will be evaluated
  • Design team awareness and/or experience

“If the POE is not specifically requested by clients, there are clear challenges providing these type of services in competitive markets, especially if clients are comparing proposals from various potential architects,” Hiromoto says. “It is difficult to communicate the added value of this enhanced service in an RFP response.”

If the design firm does consider absorbing the costs of a POE, Hiromoto points out that it still may be difficult to execute, as POEs are typically performed 6 to 18 months post-occupancy, at which time the designers have moved on to other projects and other ongoing billable tasks take precedence at that time.

At the same time, the survey also reported more than half of the firms are currently conducting POEs and almost all would like to conduct them on a majority of their projects in the near future.

Take HDR, for example. The firm has decided that the value of POEs ultimately trumps all these issue and initiates a POE process for 10 key projects in various architectural market sectors per year. “These POEs range from simple questions regarding energy and water use to more detailed POEs involving thermal comfort and envelope performance,” reports Rohlfing.

Similarly, Hendricks relates that her firm is typically not paid to do these studies, but Kirskey has decided that POEs are in important way to help the firm improve their design process.

 

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Originally published in Architectural Record

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