This case study of the LEED Platinum, Iowa Utilities Board and Office of Consumer Advocate office building, is interesting not only for its high-performance features, but also for discussion of plug loads and glare. Why are these important? As envelopes become higher-performing, and HVAC systems highly efficient, plug loads are becoming a larger piece of the energy pie of a typical building. Where we can design in efficiencies in lighting, envelope, HVAC, water, plug loads really come down to occupant behavior. The electrical engineers can add occupancy-sensor type controls to plug strips and so on, but at the end of the day this significant energy end use is determined by human behavior and dialogue and education from the beginning is key to meeting the energy goals of the building.
“The reason we exceeded our goal is because the occupants got what we were trying to do from the top down…”
“To include everyone in the decision-making process, each section chose an employee to represent them at pre-occupancy meetings, which identified strategies to reduce loads.”
The result? Modeled plug loads (including data center and fire and security related loads) were 14.5 kBtu/ft2.yr. Actual plug loads from 2014 were just 5.1 kBtu/ft2.yr. But,
The daylight design is also interesting with 95% of regularly occupied spaces daylit. Although there were some teething troubles:
“I characterize our (former) office as ‘a cave down by the river,’” Cooper said. “We had 11 windows in that whole building, and we went from the ‘cave’ and moved in here in January of 2011 when the ground was covered with snow and the sun was low in the sky. We weren’t used to any daylight, and now we had some glare.”
Glare is one of the harder daylight aspects to model, but also the most debilitating if not addressed. Our lighting team is pushing boundaries with the LEED v4 modeling they are carrying out in Light Stanza, so be sure to ask Colin and Shawn about the glare potential in your project. We never want to submit one of our buildings to an architectural journal with the words ‘Accommodations were made as needed’ to describe the post-occupancy cover ups needed!