Thermal Windows

Need some help. What is the best way to tell if the vapor barrier in thermal windows is broke.

If it’s cloudy, it’s broken. However, it may be broken and not be cloudy (a relatively new break). Therefore, I say this standard disclaimer in my report:

“We will do our best to identify windows with broken vapor barriers. However, their identification can be difficult and often depends on weather conditions. Therefore, we do not guarantee that all (or any) will be identified. All windows may not be accessible in occupied homes.”

Look for moisture in the window . Not always visable .
Look for stains that you can not rub off from outside or inside.
This is a big one look close for small 1/8 holes in the bottom of the glass and the top near the corners. These windows have been drilled to let out the moisture . Miss it and you just might have some big explaining to do . This is getting more comomon up in Canada. This does not effect the insulating value a lot but does some .
Roy Cooke sr . RHI…

Added see …

There is no “vapor barrier” built into a window. A double paned window consists of a frame and an “IGU” integrated glass unit. This glass unit is sealed at the factory under ambient conditions. Inside the igu there is usualy some kind of system to absorb the existing moisture in the air between the glass. If the seal is broken look for the signs above such as cloudyness or a dirty window that cant be cleaned. Some times if the seal is newly broken you will only see moisture inside the glass unit in the morning or evening, very hard to catch.

Good luck with this one,