Transformative Design-Build Case Study: HVAC Renovation at Polk County High School

Polk County Schools is a small, high-performing school district in Western North Carolina. The district’s sole high school was built in the early 1990’s with a two-pipe HVAC system that struggled to maintain proper humidity and temperature control throughout the year. With the building’s water-cooled chiller at its end of life and obsolete building controls, it was time for a comprehensive upgrade of the building’s systems.

Polk County Schools decided to use the design-build method to select a partner who would help identify the best solution, establish a fixed lump-sum price with no change orders, and own full responsibility for the design and construction of the project. The district selected Brady via a competitive qualifications-based selection “due to their previous experience in schools, familiarity with the type of project we were planning, and forthrightness during the interview process,” according to the Director of Operations for the district, Dr. Brandon Schweitzer.

Brady started with a system selection charrette, where they presented multiple options and discussed the pros and cons of each with the district. Based on factors such as first cost, operating cost, temperature and humidity control, ease of maintenance, and ease of construction, the district selected air handling units (AHU) with variable air volume (VAV) boxes paired with two air-cooled chillers. The project also included new controls, lighting upgrades, and replacement ceilings.

The project also qualified for a rebate of $155,176, which was used to upgrade the chillers to the ultra-quiet and high-efficiency Trane ACRB model to ensure that the new units would not disrupt any outdoor classes held nearby. The largest challenge of this project was performing construction in an occupied school throughout the school year. Construction began in the summer of 2021 with trunk lines and pipework throughout the hallways and in the common areas. Then, as the AHUs arrived, work was phased throughout the school in batches of four to five classrooms. These sections of each wing were cordoned off from students and staff to ensure their safety, and the majority of the work occurred in the evenings and nights to limit disruptions to the learning environment. Finally, all remaining areas of the building were completed during the summer of 2022 before the next school year began.

Completing invasive construction during the school year without affecting the learning environment required significant coordination and consistent communication. “Brady worked above and beyond to accommodate our school schedule and stay as hidden away from day-to-day operations as possible,” said Dr. Schweitzer. “They were attentive to detail and highly responsive to any concern I had.”

After commissioning was completed in late 2022, the project transitioned into the ongoing monitoring of the building’s performance to ensure that it meets the “performance standard” written into the contract. This performance standard commits to the District that the new system will provide proper temperature and humidity levels. Brady continues to provide remote monitoring and reporting to “tune up” the building operations as it transitions into ongoing operations.