Glenwood Junior High School Meets Codes Using Duct Sealing

For the teachers at Glenwood Junior High School in Princeton, West Virginia, it was all about comfort. Depending upon the time of the day, classrooms on one side of the building were either sweltering hot or frigid cold – and with only a few thermostats controlling the entire building, it seems like a constant fight to stay comfortable.

For the engineers, however, it was all about efficiency. The school administrators were looking to save money and the 30-year-old HVAC system was just not cutting it anymore.

In Brief

  • Building: Glenwood Junior High School
  • Location: Princeton, West Virginia
  • Engineer of Record: ZMM Architects & Engineers
  • Aeroseal Provider: Air Duct Solutions, Roanoke, VA
  • Goal: Reduce duct leakage for maximum efficiency
  • Before Aeroseal: 5,131 CFM of leakage
  • After Aeroseal: 2,359 CFM of leakage
  • Results: Aeroseal eliminated 2,772 CFM of leakage – or 6.93 tons of cooling – well below the leakage rates
    demanded by building code

To solve both problems, it was decided to replace the existing constant air volume system with a more efficient VAV system, using the existing ductwork to cut down on both complications and cost.

An initial inspection of the ductwork by Air Duct Solutions revealed that the interior of the duct system was lined with a fiberglass insulation. It was also the dirtiest ductwork they had ever seen. They could clean out the existing crud, but chances were good that leaks in the ducts were responsible for the dirt to begin with. If the school hoped to keep the ducts clean, and get the level of efficiency promised by the new VAV system, they would first have to seal the leaks.

After lengthy research to determine the best approach to sealing the ducts, it was decided to try “that new aerosol solution” called aeroseal. According to Air Duct Solutions, aeroseal would work to seal the entire duct system from the inside – despite the fact that it was lined with insulation. Using aeroseal also meant that they wouldn’t have to tear into the ceilings to access the ducts or spend time and labor trying to locate and seal the leaks by hand. In fact, Air Duct Solutions promised they could seal the entire 93 ton cooling system over Easter break and have the school ready for the students’ return immediately following the project.

The duct sealing team began aerosealing at the beginning of the holiday. They broke the entire system down into several sub-sections, aerosealing each one individually. They were finished on a Sunday and the students returned to class the following morning.

The pre and post test results told it all. They began with 5,131 CFM (cubic feet per minute). Aerosealing eliminated 2,772 CFM of leakage and brought the system down below the leakage rate demanded by building code.

“On this project, the Aeroseal process saved tons of cooling,” said Sam Butzer, project engineer, ZMM Architects & Engineers. “We’ll have a more efficient system using less energy doing a much better job heating and cooling the building. When it comes to remodel or renovation projects there really isn’t an alternative.”


As 2010 ASHRAE code kicks in, this is the only way to go. I’m not going to have someone try to find and seal all the little holes manually. With aeroseal, you don’t have to take off the insulation or uncover hidden ductwork. On this project, the aeroseal process saved tons of air that was being cooled and then lost through leaks in the ductwork. Now we have a more
efficient system, using less energy, doing a much better job of heating and cooling the building. When it comes to remodel or renovation projects, there really isn’t an alternative.”

San Butzer
Project Engineer
ZMM Architects & Engineers

There were a lot of questions beforehand regarding the use of the spray sealant in a classroom setting, but the results proved any prior concerns unnecessary. The sealing was completed in the evening and the school was open for business the next day. I have not heard of any complaints whatsoever regarding the smell or the possible spread of sealant in the classroom. Everybody was satisfied.”

Gary Bailey
Mercer County Maintenance Director
Mercer County Office of Education

About Aeroseal Technology

Before/After Aeroseal
  • Developed at Lawrence Berkeley National Laboratory in 1994.
  • Research for aeroseal technology was partially funded by the U.S. Department of Energy.
  • Aeroseal is the only duct sealant technology that is applied from the inside of the duct system. It is delivered as a non-toxic aerosol mist that seeks out and plugs leaks.
  • Aeroseal has proven to be 95% effective at sealing air duct leaks.

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