Hi everyone,

   I am new at understanding how to read an infrared camera. I want to see what a wall looks like with or without insulation. Here's my question:

Does there need to be a temperture difference from the inside of the house  to the outside to see if there is insulation in the walls?

What should that difference be? ie 15 degrees.

Do you ask the homeowner to turn up the heat in the winter or turn on the A/C in the summer.

How best do I find out if there is insulation in those walls?

Thanks for your comments

Judi Lyall w/ SHE BUILDS GREEN

Views: 1915

Replies to This Discussion

Thanks John, i appreciate you taking the time to answer my quirey. do you know what the indoor ambient temperature was at the time of the photo? thanks again for helping me understand.

Dale,

I looked up the BD test.  At the start of the Blower Door the inside was 70 and the outside was 43.  From what I remember, the outside didn't change much all day.

Judy

An important thing to remember is that the delta T (temperature difference) that's needed refers to "surface" to "surface" differences when investigation insulation issues.  Ambient temperatures can be a little misleading sometimes when we are investigating energy transmission issues.  For example, If the interior has a surface temperature of 70F and the exterior ambient is 30F we would think that the heat would move from inside to outside (2nd law of thermodynamics - hot to cold).  But what if you are looking (from the inside) at a south wall that has been effected by the sun for a few hours?  That wall might be 120F.  Now the heat movement is from outside to inside.  Missing insulation would look warm from the inside.  And if you go over and look at a north wall, which is not effected by the sun, missing insulation would look cool.  So, I always ask myself: What's the direction of the heat movement surface to surface, inside to outside or outside to inside?  And then I identify the color of the path of least resistance.  The framing members should be the path of least resistance in a fully insulated wall.  If insulation is compromised or missing then it will show as the path of least resistance.   That being said, air leaks usually require much less of a temperature differential, maybe only 3 degrees F and that is ambient to ambient, not surface to surface.  The sensitivity of the camera detector system can certainly have a positive or negative effect on the delta T needed in both scenarios.

RSS

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Home Energy Magazine's blog post was featured
16 hours ago
Hannah Finch posted a blog post
16 hours ago
Profile Iconpank and Carrie Sturrock joined Home Energy Pros
17 hours ago
tedkidd commented on Amber Vignieri's blog post Chicago Winter No Match for Retrofitted Logan Square Building
"This case study is an example of how hard it is simply to do a compelling case study. Everyone has…"
19 hours ago
B. M. Lubin posted an event
Thumbnail

GPRO Construction Management Class at USGBC-LI headquarters in Hauppauge, NY at USGBC-LI Headquarters

September 19, 2016 at 9am to September 20, 2016 at 2pm
Taught by industry experts using real-life classroom exercises, GPRO CM gives experienced building…See More
23 hours ago
B. M. Lubin is now a member of Home Energy Pros
yesterday
Eric Kjelshus replied to tedkidd's discussion Dear DOE, PACE sucks - please fix or make it go away...
"Most HVAC system upgrade - change outs and attic seals-R-49 end up $20-30K   Most house -…"
yesterday
Brennan Less replied to Rob Madden, Solar Home Broker's discussion Indoor Air Quality Monitors and Meters
"Anyone interested in this realm should check out the EPA-funded project at the South Coast Air…"
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service