Any idea as why these two windows (left and right sides) are different?
The left one might have lost its seal if not then the right one could have a screen on out side adding to less heat loss.
In the pic on the right, it seems one of the panes doesn’t have, or has the wrong, Low-E coating.
Jeff, I would not repeat what was discussed earlier.
Good info… but… in the posted pic, to me, there appears to be a visual difference, where Chuck did not indicate there was in his example. I could be wrong… I just scanned the other thread for highlights.
The right window is a casement, the left appears to be fixed. A casement window will have the screen on the interior. The screen itself will be warmer (assuming that the exterior temps are cooler - as indicated by the air leakage through the crank mechanism) and will act as an attenuating medium.:mrgreen:
So the next question is… did the window have a screen on it?
The screen accounts for the visual difference between the windows - Methinks. Plus, I can see the tabs on the right margin.
I assumed the possibilty of screens, but couldn’t really tell if present, and I know that there are different Low-E coatings that would give a similar look if mismatched. I guess I ruled out the screens thinking the OP would have removed them prior to his scan if it had them to begin with. That’s what I get for assumin’!
Chuck, you are correct about the screen, however I really don’t think that the screen would account for more than 2 Deg.difference. Although I did not try the scan without the screen so I might be wrong in this. However the real issue IMHO was different. And no, this is not Low-E coating.
I do. The screen, itself will account for a significant amount of the incident radiation detected by your imager and of course it will have its own temperature, emissivity and reflectivity separate from the glass. You shot the image at an angle of less than 90°. The greater your angle of observation, the greater the amount of total incident radiation will be contributed by the screen, because it will appear denser, up until the point that the angle of observation reduces the emissivity, then the reflected temperature of the room will increase its influence. Factor in that the screen will be somewhat transmissive and you have plenty of variables to account for such a slight apparent temperature difference (looks like about 1.5C° to me). Until you measure glass to glass or account for the other variables we can’t know if there is a real temperature difference at the window glass.
I’m happy to hear your theory, I learn something new every day.
Well, I’m really happy to learn from you and now that you explained it to me, I think you are right. My theory, basically, was very simple. The homeowner had lots of moisture in the fixed portion of the window that was removed by making a small hole at the bottom of the exterior pane. This hole was not plugged. So before your explanation I was sure that this was the reason for the temperature difference. :roll:
So the left pane had a broken seal, now that explain’s it!
That could easily be the cause or at least a contributing factor.
We have lots of variables that could contribute to the apparent temperature difference, so I personally would not try to hang my hat on any one in particular unless I could eliminate the others.
My theory was based on the info that I had available to me from the images. None of that invalidates your theory either. I certainly would not argue against your theory.
Thank you, Chuck. Another great lesson learned.
Which one… to give out ALL of the pertinant information at the start of the thread???
Hey, you were suppose to think thermally.:mrgreen:
Ahhh, butt see, I am still a student of the IR. I am here to learn what I can, before I take the next step. I have many opinions (as Chuck will testify to) but little on-hand knowledge. Doesn’t stop me though. We all got’s to start somewhere!
With that being said… I think even that other guy in Texas knows that a window with the Argon Gas removed will THERMALLY show different! :mrgreen:
Jeff, you have to admit that if I would reveal ALL the details then there would be no need for pictures and we would never learn a valuable lesson about many variables that may affect the thermal scan.
Oohhhhhhhhh… so now you’re claiming this as an EDUCATIONAL thread, and NOT an I NEED HELP thread. I see how you are!