Gallego Intermediate School

TYPE: Education

School Seals Leaky Ducts, Avoids Cost of System Replacement

When contractors removed ceiling tiles during a floor-to-ceiling renovation of the Gallego Intermediate School in Tucson, Arizona, it feared for the worst. The ductwork was in such bad condition, replacing the entire air duct system seemed to be the only option for the budget-conscious school. The building’s HVAC system included 34 individual units, each with its own supply and return ducts, all made of duct board that was literally falling apart at the seams. Some of the air ducts were so bad that they made air duct leakage testing impossible. The cost of new ductwork in this scenario would be significant.

After doing a cost estimate to replace ductwork, the school district knew it couldn’t afford the estimated $200,000 to replace the existing air duct system. Plus, the school was set to open in three months, and replacing the ductwork would have taken close to six months. This was not an option.

Project Overview
Building Gallego Intermediate School
Location Tucson, Arizona
Aeroseal Contractors Excel Mechanical, Inc. (GreenSeal)
Contract Engineer Kelly Wright & Associates
Goal Repair damaged, leaky ductwork within time and budget constraints for school renovation
Before Aeroseal 49k CFM of leakage
After Aeroseal 8k CFM leakage
Results Sealed the entire school air duct system to attain a 5% leakage rate at 25% lower cost than air duct replacement

When contractors removed the ceiling tiles, they wanted to replace all of the ductwork. It was in such bad shape, but it was simply not in the budget. Aeroseal duct sealing proved to be much less expensive than replacing the ductwork and it took only a matter of days to complete the job, keeping us on schedule.

Cindy Bova
Energy Project Manager
Sunnyside School District

Faced with an air duct replacement cost that was far too expensive, a consulting engineer working on the project suggested the school consider Aeroseal duct sealing technology. The cost of Aeroseal duct sealing was lower than the average cost to replace HVAC ductwork. Aeroseal contractor Excel Mechanical, Inc. (GreenSeal) was called and in just a matter of days, the project was underway.

Given the poor condition of the existing ductwork, the Excel Mechanical crew began reconnecting and repairing the most dilapidated portions of the ductwork using mastic and tape. After hand sealing, air duct testing showed a total leakage rate close to 49,000 CFM. Aeroseal duct sealing was used to reduce duct leakage more than what mastic/tape could do alone.


It took GreenSeal less than two weeks to seal all 34 air duct systems (supply and return) using Aeroseal. The final results showed total leakage reduced to 8,000 CFM. The school achieved an 85% leakage reduction and the 5% leakage rate it was targeting. The total cost of Aeroseal was a fraction of duct replacement and best of all, the school opened on time.

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