What is a Total Duct Leakage Test?

view from below of an air duct

What is the importance of total duct leakage testing?

When your HVAC system isn’t evenly cooling or heating your home, there may not be anything wrong with the HVAC system. Often, the problem is that the treated air isn’t being evenly distributed through the air duct system. At this point, an option such as duct leak testing in Fort Worth, TX may be worth considering. If you find yourself in need of this service, our team can always be there to help. Reach out today at 817-781-8781 if you would like to learn more.

Are there different types of duct leakage tests?

The goal of duct leak testing is simple, starting with finding if there is any leak, which is done by measuring the airflow.  This can be done in one of the following methods:

  • A duct leakage tester with a blower door
  • A flow hood
  • A blower door with a pressure pan
  • A blower door only 

There are two types of air duct leaks: benign and malignant. It is the malignant leaks that are the leaks to be concerned with because they send conditioned air into unconditioned spaces, in short, wasting energy. 

Which method of duct leak testing is performed will be determined by which type of leak the technician is seeking. Because the benign duct leak isn’t as big of a concern, because it is within the duct system, the most common type of duct leak testing is done by the duct leak tester with a blower door. 

What is the standard process of duct leak testing? 

In the first step in air duct leak testing, the technician will seal all the openings with HVAC tape in the duct system, including the return and supply registers. This step in the process is the most time-consuming part of duct leak testing. 

Next, the fan is turned on to depressurize the duct system to a rating of less than 25 pascals. This is the amount of air measured that moves through the fan, referred to as the CFM. This is an important number in calculating any duct leak measurement.

What are the standards for duct leakage testing?

The IECC (International Energy Conservation Code) requires building thermal envelope testing to fall per the following guidelines:

  • ASTM E779
  • ANSI/RESNET/ICC 380
  • ASTM E3158
  • ASTM E1827 

These guidelines state that the measured air leakage does not exceed a measurement of 0.40 CFM75/ft2. 

How long does an air duct leak test take?

A professional air duct leak testing on an average-sized home will typically take up to 2 hours.  The results of the air duct leak testing are usually available on the spot and the technician will email a copy of the report to you as well. 

How much does duct leak testing cost?

This can vary based on the size of the house, but on average, the cost for a typical-sized home for duct leak testing can range between $500 and $1,500.

How much duct leakage is normal?

Any time a new HVAC system is installed, the contractor will either perform air duct leak testing or recommend you have a third party perform the test. If the results are at 15% or higher of leakage, the air ducts should be repaired or replaced. 

Once this is completed, the homeowner should have a third party perform another air duct leak testing to ensure that there is less leaking, ideally no more than 6%. 

What are the benefits of air duct leak testing? 

There are three key benefits to having duct leak testing done for your home, and as a homeowner,  you’ll find these to be the best reasons: 

  • ENERGY EFFICIENCY: This is the best reason to have air duct leak testing performed. When there are gaps or leaks in the duct system, the conditioned air leaks into the space around the duct instead of getting to the living area below. Thus, you’re adjusting the thermostat constantly which results in higher energy bills and causes the HVAC system to work harder and longer to reach the desired temperature.
  • IMPROVED COMFORT: Air duct leak testing will let you know what needs to be repaired or replaced. This will lead to your home being more comfortable with each room evenly cooled or heated. 
  • INDOOR AIR QUALITY ENHANCED: Air duct leak testing will let you know that the ducts need to be repaired or replaced to prevent allergens, dust, and other pollutants from infiltrating your home. These are issues that can hurt your home’s indoor air quality, affecting the health of your family. 

Closing The Gap

How often should you have duct leak testing done? There isn’t a recommended schedule for duct leak testing as with changing or cleaning the air filter (which is every 30 days) or the annual professional inspection and cleaning of your HVAC system.  But there are indications that you may benefit from air duct leak testing, such as: 

  • Your energy bills have increased more than normal.
  • The home isn’t evenly cooled or heated, some rooms are cooler/warmer than others.
  • Every room isn’t consistently at a comfortable temperature.
  • A visual inspection by you, or your HVAC technician finds broken, loose, tangled, twisted, or torn sections of the ductwork.

At the end of the day, air duct leak testing is a benefit to your home and your family, both financially and health-wise. If you would like to get help from a professional, just reach out to our team. Call today at 817-781-8781 if you would like to schedule this service.