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Duct Leakage Testers

Duct Leakage Testers

Duct leakage testers are widely used througout Australia and the world by HVAC professionals. Duct leakage testing, also known as duct leakage diagnostics or duct leakage evaluation, is a process used to assess the efficiency and performance of heating, ventilation, and air conditioning (HVAC) systems in residential, commercial, and industrial buildings.

The testing is conducted to determine the amount of air leakage occurring within the ductwork, which can significantly impact the overall efficiency of the HVAC system and result in energy wastage, decreased indoor air quality, and higher utility bills.


The main objective of duct leakage testing is to identify and quantify any leaks or breaches in the ductwork that may allow conditioned air (either heated or cooled) to escape into unconditioned spaces like attics, crawl spaces, or wall cavities. Conversely, duct leakage can also allow unconditioned air from these spaces to infiltrate the ducts, affecting the temperature and air quality delivered to the living or working areas.

Testing Process

Duct leakage testing is usually performed by certified HVAC technicians or energy auditors using specialized equipment. The most common testing methods involve either pressurizing or depressurizing the duct system and measuring the airflow and pressure differentials to calculate the amount of leakage.

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How Duct Pressure Testing Typically Works

  • Pressurization Test: The technician seals off all the registers and grilles throughout the system and then uses a fan to blow air into the ducts, increasing the pressure inside the system. By measuring the airflow supplied by the fan and the resulting pressure, the technician can estimate the amount of air leaking from the ducts.
  • Depressurization Test: This method is essentially the opposite of the pressurization test. The technician seals off the return side of the duct system and uses a fan to create negative pressure in the ducts. The air drawn into the system through leaks is measured and used to calculate the overall duct leakage.
  • Reporting and Recommendations: After conducting the duct leakage test, the technician will provide a detailed report that outlines the amount of duct leakage as a percentage of the total airflow. Based on the results, they may also offer recommendations for sealing or repairing the leaks to improve the system’s efficiency and performance.

Benefits of Duct Leakage Testing

  • Energy Savings: Identifying and sealing duct leaks can lead to significant energy savings by preventing conditioned air from escaping and reducing the workload on the HVAC system.
  • Enhanced Indoor Air Quality: By sealing duct leaks, the potential for pollutants, dust, and contaminants to enter the system is minimized, resulting in better indoor air quality.
  • Improved Comfort: Sealing leaks helps maintain consistent temperatures throughout the building, enhancing comfort for occupants.

Duct leakage testing is a valuable diagnostic tool that helps identify and address inefficiencies in HVAC systems, leading to energy savings