By Darrick Cope, InterMountain ESD

In 2021, after spending 27 years in the Helix School District (14 as the Superintendent), I had the opportunity to take a position as the Director of Facilities at the InterMountain ESD. One of the first tasks assigned to me was to come up with a solution to the HVAC issue they were having at their main building in Pendleton.

In 2019, the IMESD enlisted an engineering firm to draw up an estimate to replace the two RTU units that were installed well over 25 years ago. These units cost the IMESD thousands of dollars each year to maintain, were not efficient and replacement parts were getting extremely difficult to locate when needed. In a nutshell, the firm came back with a bid that ranged from $2.5 – $3.0 million to remove and replace the two units. With only $500-$700K budgeted in the capital projects fund, IMESD Superintendent Mark Mulvihill ended the meeting after about five minutes.

Fast forward back to 2021. I had a couple of my contacts at Gordon’s Heating and Cooling in Pendleton assist me in developing a proposal to go in a totally different direction. My proposal was to install nearly 70, one-to-one, ductless mini-splits throughout the building. Going with this plan did make me nervous and immediately raised some concerns. The first was how difficult would it be to locate adequate power sources for 70 mini splits in the 1962 building. A second concern was if our power consumption would greatly increase after adding all these units. Lastly, since the mini splits do not take in outside air, we needed to figure out an inexpensive system to circulate air in the building.

I asked Derek Oldenburg of Gordon’s Heating and Cooling why are mini splits so efficient and why are they becoming so popular? He stated, “mini splits (also known as ductless heat pumps) are the technology of the future. Mini splits use inverter technology, which results in dramatically lower energy costs and in well designed, systems, greater comfort. In larger facilities it’s common to have one central HVAC system. The problem with that is when the system goes down the whole facility is down. The beauty of mini splits, besides the energy savings, is if there is a problem it’s one office not the entire facility. The comfort and freedom everybody gets in choosing their own environment conditions results in happier customers for us.”

Utilizing mostly ESSER dollars and some general funds, Daikin ductless mini splits (heat pumps 9-24k btu) were installed in every office and conference room in December of 2022. Remote controls allow each staff member to program their units to their desired temperature. Two makeup air units (MAU) were installed to provide fresh air circulation, utilizing the existing return and supply ducts. The MAUs use natural gas to heat the exchanged air during the winter months to around 60 degrees, so cold air isn’t being blown into the building. The power for the units mostly came from the service panels that supplied the original RTUs. The final phase of this project involves the hallways and bathrooms, which to date have not had units installed. Total cost for this project was under $500,000.

All in all, it was a great project. Everyone is happy to have the ability to choose their own desired office temperature. The biggest win is the energy savings for heating and cooling a very large, 1962, former hospital building. When comparing the power bill from 2023 with that of 2022, the kilowatts dropped by half. For example, August 2022 total kilowatts 43,200, average per day 1,490 at a cost of $134.58 a day, In August 2023, total kilowatts 20,160, average per day 695 at a cost of $76.89 a day. This is an amazing savings we have been experiencing

monthly, since the units were installed. In addition, the natural gas cost for heating has dropped substantially. The highest natural gas cost to heat the building using the RTU was right at $4,000. For that some month a year later, it was $400. Aside from a few smaller devices, the only natural gas we use is to heat the air to 60 degrees in the MAU units. Not only were the energy saving amazing, but we also received a incentive check from Oregon Energy Trust for $20,475.

Ductless mini splits may not be the answer to all your HVAC needs, but I would strongly recommend considering them when you are planning a renovation or new construction project.

Published in Oregon School Facilities Management Association, Fall 2024