Dbl-Glazed windows leak gas?

[Sherry]

I recently had an energy audit of my home.  While talking to the technician who did the audit, he mentioned to me that he had attended some kind of energy conference.  He said that some window salesman or expert at the conference confided to him that those double-glazed windows that are supposedly energy efficient b/c of the gas between the 2 panes of glass, end up leaking out all that gas w/i about 5 years.

Does anybody have any experience w/those types of windows, or has anyone else heard the same thing?  Since the windows are expensive, it would seem foolish to pay that extra $ for only 5 yrs. of savings, if what the technician said is true.  Comments?

[glenn kangiser]

I have seen a lot of leaking dual pane windows - not necessarily gas filled though.

[dug]

From what I understand, if the windows are manufactured at a significantly different altitude than where they are installed the argon will leak out. Even if installed at the same altitude as was manufactured the argon will leak if it travels over a high mountain pass during shipping. To combat this they install capillary tubes which allow inside air pressure to equalize without the argon escaping.

[John Raabe]

This seems to be a pretty good article on window technology and inert gases between the glazings.

http://www.engext.ksu.edu/henergy/envelope/windoors.asp

Dual pane glazings don't last forever. My 1983 house has lost the seals on about 1/3 of the units. I'm reglazing them in stages. In 1987 we built an addition with better windows (but from the same manufacturer) than the earlier part of the house. That section had argon filled units and so far not a single leak. They were manufactured and shipped from about 50 miles away.

[Don_P]

We built ours prior to argon, they used a mylar film in the double pane with a low E coating. I had the coating faced to trap heat on the solar facing and to reject sunlight on the west facing windows... the latest hot tip at the time. Almost all of those have fogged. We built at above 5,000 ft in one area with windows made at a couple of hundred feet prior to capillary tubes, the local glass company got alot of business. We could see the windows belly and within a day or two crack.

I've wondered if the energy used in replacing fogged windows is greater than the savings during their life  .