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


Views: 1203

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.


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.


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.


Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network.

Latest Activity

Profile IconDenise Cooper, Maren Cooke, Steven Antonini and 1 more joined Home Energy Pros
Crosbey Archery joined Allison A. Bailes III's group


HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements,…See More
Crosbey Archery commented on Ottawa Furnace Filters's blog post Some Useful Information about Furnace Air Filters
"This post is really helpful especially to those homeowners who are still confused on what to…"
Diane Chojnowski posted videos
Diane Chojnowski posted a discussion

Incentives & financing options for home energy upgrades

Energy.gov has a useful database of incentives and financing options for home energy efficiency…See More
George Kopf commented on Home Energy Magazine's blog post My Fall Into The Smart Home, Lazy Life
"Matt, Another way of looking at this is that by freeing up my time/brain power, I can give more…"
Chris Laumer-Giddens's blog post was featured

Sparky Doubled the Air Leakage in this Home!

Sparky Doubled the Air Leakage in this HomeThis is the home.This is the hole that Sparky…See More
Chris Laumer-Giddens posted a blog post

Sparky Doubled the Air Leakage in this Home!

Sparky Doubled the Air Leakage in this HomeThis is the home.This is the hole that Sparky…See More

© 2015   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service