GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

What do you do when you can’t find duct leakage issue?

user-979926 | Posted in Energy Efficiency and Durability on

Conducted an audit today on a manufactured home with a rectangular duct board system in the belly. Duct leakage testing resulted in NO reading at 25 pascals. We crawled under the entire home following the trunk lines and found no visible signs of broken or disconnected ducts that could explain such high leakage. Has anyone out there ever ran into a situation like this? If so what did you do?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    I'm not experienced at this type of work, and I look forward to comments from more experienced GBA readers. Here are my thoughts:

    1. Do the ducts disappear into the insulation installed in the floor assembly? In other words, are there inaccessible and invisible seams -- for example, joints between the ducts and the register boots? If so, there could be disconnections that are invisible.

    2. Are you sure that your equipment is properly calibrated and working properly? Equipment can break.

    3. If you are using a Duct Blaster, I suggest that you contact the technical help line of the Energy Conservatory (the manufacturer of the Duct Blaster). The employees of that company are knowledgeable and helpful. Here is the contact information:

    The Energy Conservatory
    2801 21st Avenue South, Suite 160
    Minneapolis, MN 55417
    Email: [email protected]

    -- Martin Holladay

  2. walta100 | | #2

    You could try putting a fog machine in the return duct and run the fan and then look for the leaks.


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |