Having an old-timers moment...

[David A. Andersen]

Spectrally selective coating. A coated or tinted glazing with optical properties that are transparent to some wavelengths of energy and reflective to others. Typical spectrally selective coatings are transparent to visible light and reflect short-wave and long-wave infrared radiation.

Interesting!

Thanks Kevin!

[Kevin A. Richardson]

Originally Posted by dandersen

Interesting!

Thanks Kevin!

Your welcome

You might want to also take a look at RESFIN. I've used it twice in the past to help clients with selecting window replacements when I was modeling their home for Home Energy Performance Surveys. It's a very cool "free" software.

Kevin

[David A. Andersen]

Originally Posted by dandersen

Interesting!

Thanks Kevin!

But... now that I read that again, IR doesn't pass through ANY glass!?

[William Warner]

Originally Posted by dandersen

But... now that I read that again, IR doesn't pass through ANY glass!?

Long wave doesn't (or very little)... short wave does. Or at least that's what I was taught. Hence how/why a greenhouse works.

I wonder if the absence/presence of argon gas (or dissimilar gases) could also create what you saw. (Not sure...) What you recorded resembles the difference between single pane and double pane side by side comparisons looking through a long wave imager. You've certainly got my interest peaked Dave. I believe this will certainly take more investigation than an IR imager can provide to figure out.

[rbibler]

This is going to open a new window in IR.. L.O.L. Looks like one should put together a hand book on windows and how each window or type of covering views under IR.

With all these new windows and NEW window products on the market one could make a mistake in there findings.

Best

Ron

[Dan Bowers, CMI]

If you measured them and there is a 2 degree difference - Who gives a *****. What is the problem? Is there anything important OR are you just wasting time on this.

[David A. Andersen]

Temp differential is not the only issue.
That is why I did not add them to the scans.

What causes this may cause a significant condition in comfort and utilities.
The rooms are 45 - 60% glass. They have a significant south exposure.
The exterior patio and swimming pool multiply the incident radiation well above the normal exposure to the sun through specular and diffuse reflection.

Most importantly, they may not be performing as intended by the manufacturer.

If it is seal failure, it will turn white and ruin the million dollar view of Nashville's historic Music Row (which is a significant deterrent to the client) .

When I see something like this, I want to know what I'm looking at.
I don't consider it to be a waste of time. If you do, don't attend this thread.


Thanks Bill, that is very true. So that definition is 50% correct!?
Anyone know the transmission of glass?

I wonder if the absence/presence of argon gas (or dissimilar gases) could also create what you saw.

Yes it will. We have documentation on this from past cases, but in this case the building is new and we would expect the same batch of windows to be installed.

We are asking the glass contractor for this information as it is the first consideration (the windows were broken and replaced with different type windows).

Some windows are "dry air" filled and some have other gases which perform differently. This is our second expectation.

Orientation of installation may be a factor. The Mfg can provide this information.

Lastly is that the windows may have failed (not likely as they are visibly different).

[David A. Andersen]

Take a look at what Rich posted. That info on glass types shows that orientation and design effects reflection of energy and allows light transmission directionally.

If the windows are in backwards, they will not function as intended. Simply turning them around may change things.

[Jason Kaylor]

Have you thought about renting a short wave, and shooting them with that? It would be very interesting to see what there is to see via short wave.

If you are have a hard time finding one, give Greg Stockton at Stockton Infrared a call. He has one he rents out. Be ready to put down a big deposit.

JJ

[David A. Andersen]

I don't have the "funding" for that research!

I have heard that short wave cameras are more susceptible to reflection in this type of scan but is able to see transmission through glass better. I have seen scans at school where they can see the HVAC ducts from the exterior through the buildings windows with shortwave.

[Jason Kaylor]

By the way, Testo makes one of the most amazing meters on the market called the 435. It is an HVAC / air flow tech's dream meter. I bring it up, because it has something I have never seen on any meter on the market. It actually has an R value and U value probe. It would be very handy to IR guys or energy auditors. The problem is the 435 is not cheap. $1,500 ball park for the wireless version, which you need that version to use the R / U value probe.

Testo 435

435 R / U Value Probe

Jason Kaylor – JJ
VP of Specialty Products
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