Simply put a one way valve for the removal of moisture from between thermal pane windows is a worst an ignorant claim and at best flagrant lie.
If a one way valve is installed it must dissipate water vapor, therefore by definition the valve should close on the cooling cycle of the air and recreate the same conditions that drew water into the cavity.
... the war of FOG
I intend to sharing most all of the public domain: information: trade secrets and processes for defogging windows so you can make informed decisions.
Most all of the processes and methods are now in the public domain and there remain a number of companies still trying to profit from the work originally done by Crystal Clear Window Works Canada.
At one point in time Crystal Clear Window Works Canada was the only company who had secured and developed IP rights, trade secrets and designs for the processes and methods of removing moisture from foggy windows. When the process is done properly the system works very effectively - when done by cowboys ... it is little more than a scam.
If you are considering purchasing a dealership, franchise, business system, license, country license or purchase defogging products or training for moisture removal from failed thermal pane windows we can help with due diligence and research.
You should read this site carefully and proceed with caution as there are many scam artists and fraudsters to watch out for and information that you should understand.