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Aging HVAC System and Poor Ventilation Spurs Comfort Upgrades

The aging HVAC system at the Oregon Department of Fish & Wildlife’s district office complex in Corvallis resulted in high energy costs and limited comfort control for tenants. The HVAC system struggled to provide consistent temperatures across 13,200 square feet of conditioned floor area, made up of four separate buildings sharing concrete walls and the various zones within the buildings. The building managers knew any retrofit project would be difficult due to the complex’s unconventional arrangement.

“We needed to replace the heating and cooling system because it was old,” said Ryan McCormick, Chief Engineer at Oregon Fish & Wildlife. “Looking into it, we realized there was a better way to do it, with energy savings that would help cover longterm costs.”

Separating Ventilation to Improve Air Quality and Efficiency

Due to the complex’s size and the zonal layout of the combined buildings, building management resolved to do a partial replacement of their HVAC equipment, using the very high efficiency dedicated outside air system (also referred to as VHE DOAS) approach. They started with the replacement of one RTU with plans to upgrade their second RTU servicing additional areas of the building if the new, high-performance HVAC system proved successful.

DOAS applies the concept of separating heating and cooling from the ventilation system, which allows for optimal control of each of these critical building functions. The new system improves this concept by focusing on efficiency and pairing a high efficiency heating and cooling system with a very high efficiency heat recovery ventilator (HRV). This combination results in:

  • Improved indoor air quality due to filtered 100% outside air being brought into the space
  • Lower energy bills because the very high efficiency HRV allows for a smaller heating and cooling system that runs less often
  • Precise temperature and humidity control


After experiencing heating and fan energy savings, along with a significant reduction in monthly peak demand, the building management team immediately began to plan further HVAC upgrades, including replacing the remaining RTU, across the complex. And while building management enjoyed the savings on monthly energy bills, the building’s tenants appreciated their daily experience of improved indoor air quality.

“After the installation, everyone said ‘wow, this air actually feels fresher’,” said McCormick. “There was definitely a noticeable difference—this was a much more comfortable environment. Other people in areas that hadn’t yet been converted kept asking ‘when are we getting our air fixed?'”

Download the case study here: Government Office High Performance HVAC Case Study

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