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Achieving Profitable Sustainability

How an inspired engineer helped transform his building from energy sink to EnergyStar.


Tharin Robertson, Lead Engineer“Colliers promotes rigorous social and environmental responsibility.  As Facility Manager and Lead Engineer, my main goal is the safety of our tenants and of our environment.  Hopefully, our efforts will inspire others to take action towards their own sustainability goals.”
Tharin Robertson, Lead Engineer | Colliers International


Originally built in the mid-1970s, 130 East John Carpenter Freeway in Irving, Texas served as a regional hub for General Motors through 2004. The building sat dormant until 2006 when Jenterra LLC purchased the property and transformed it into a shining example of modern sustainable design. Right away, Jenterra upgraded the building’s lighting system, installed new low-flow water fixtures, and introduced sky-lighting to the completely renovated central atrium.

While the aesthetic remodel drew new tenants, no significant improvements had been made to the building’s HVAC system since the original construction. Energy prices in the region steadily increased, maintenance costs continued to rise for the building’s aging mechanical equipment, and the vintage systems were beginning to lose their battle against the hot, humid Texas summers. 

jenterra-atrium-1Jenterra selected Tharin Robertson to head up building operations at the newly remodeled site. Driven by his love for the environment and a strong sense for corporate social responsibility, Robertson identified the facility’s outdated HVAC mechanical systems as a critical factor in the facility’s future success. The inefficient plant was a burden to the environment, the tenants, and ultimately to the facility’s operating budget. Recalling his conversation with the building owners and their Board, Robertson said, “this is going to cost us now, or it’s going to cost us later.”

With full Board support, Robertson spearheaded a one-year HVAC retrofit project with design firm Kahn Mechanical that included a new, cutting-edge central chilled water plant, cooling towers, and pumps. Custom air handling units reduced humidity and dramatically improved indoor air quality. Variable speed drives were installed on high-efficiency pump and fan motors. Robertson recalls the challenges he faced during the project: “When we started, the building was at 95% occupancy, so tenant support was extremely important. Though inconvenienced at the time, our tenants are all very happy with the outcome.”

jenterra-atrium-3The Jenterra Building has seen a huge return on their investment. Robertson had originally predicted an 18% reduction in HVAC-related energy expense. Since completion in 2010, the building has consistently recorded expense savings far exceeding 60%. “The reduction of our overall power bill is absolutely tremendous,” says Robertson. The facility also holds an Energy Star rating of 84, ranking it among the top commercial buildings in North America. 

For Robertson, this is just the beginning.  With Jenterra building, now managed by Colliers, he has the support of a larger team to continue seeking out ways to improve operating efficiency and reduce operating costs through profitable sustainability.  Next on his list: an expanded recycling program, occupancy sensors, and LED lighting. All of these measures position Robertson and his facility closer to IREM’s Certified Sustainable Property designation—an important distinction both to Robertson and to Colliers.  

"To date the certification process has been very easy. The web site is a wonderful tool, the challenges are interesting.  You're helped step by step in the certification process and the database lets you keep track of your accomplishments. Colliers promotes rigorous social and environmental responsibility.  As Facility Manager and Lead Engineer, my main goal is the safety of our tenants and of our environment. This certification demonstrates our dedication. It gives us bragging rights locally and throughout the Colliers portfolio.  Hopefully, our efforts will inspire others to take action towards their own sustainability goals.”

IREM Sustainability is designed to help property managers pursue efficient and sustainable buildings-- from insight to action-- and consists of three integrated parts:

  • The IREM Green Per Square Foot database
  • The IREM Sustainable Property Challenge
  • The IREM Certified Sustainable Property Certification

For more information, please contact:

Todd Feist,
IREM Sustainability Program Manager 

Nathalie Osborn,
IREM Sustainability Program Manager


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