GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Alpen Windows – Heat Mirror

jackofalltrades777 | Posted in Green Products and Materials on

Alpen windows have a pretty impressive line-up (R-7) that can be used in high-elevations (5,000+ feet). My question is about the HEAT MIRROR technology. There was some problems years ago with the mirror technology failing but that’s been a while.

How reliable is that technology?

Can the windows last 30+ years like a standard double pane window?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    No one knows the answer to your question. It's a pretty firmly established fact that the first generation of Heat Mirror glazing with suspended plastic films had durability problems.

    Alpen Windows claims that the current generation of Heat Mirror glazing is improved. Time will tell.

    In Europe, where triple glazing has become standard in many countries -- for all intents and purposes, triple glazing has been code-required in Sweden for over 30 years -- no one uses Heat Mirror glazing or suspended plastic films.

  2. jackofalltrades777 | | #2


    Good points. Do you know of a European triple pane window system that will work in high elevations (5,000 feet) ?

  3. GBA Editor
    Martin Holladay | | #3

    When it comes to installing an insulated glazing unit (IGU), whether double-paned or tripled-paned, at a high elevation, the best solution is to try to locate a manufacturer of IGUs or windows near where you are building, ideally at a similar altitude -- and ideally connected to your building site by a road that doesn't drop down to significantly lower elevations or rise to a very high pass above the altitude of your building site.

    That's not always possible, however -- so the usual solution is some type of breather tube that results in the loss (partial or total) of the argon. Some problems aren't easy to fix.

  4. onslow | | #4

    Peter L,

    I have had my Alpen windows for two years now and enjoy them greatly. Marvin, Integrity, and Sierra Pacific would not ship to my altitude (8000') with argon and I seem to recall that Marvin didn't want to ship over 5000' which oddly leaves out most of Colorado including Denver. The film is invisible unless you wear polarized glasses indoors and so far not a hint of issues despite very intense sun load in my location. I also hesitated due to the Heat Mirror history, but that was now almost 30 years ago. Triple glass units are notably heavier and if you have ganged windows such as I do, then the installation could get very exciting to say the least. My windows came through the Eisenhower Pass tunnel which is about 10,000' with no issues and the little argon balancing bags seem to have done their job. A minor annoyance to hide the capillary tubes after installation if your not handy. It does take some careful handwork. If you are building in the mountains you may well like the very tight seal I have enjoyed with the casement and awning windows. The wind noise is unnoticeable at the windows even when the house is shaking.

  5. jackofalltrades777 | | #5


    So what would happen if the manufacturer did NOT include breather tubes/balloons and shipped to higher elevations? Would the gas leak out or would other problems arise?

    Argon gas eventually leaks out anyways over time so to me that is not a concern. I just don't want the windows cracking or developing condensation leaks.

  6. BillDietze | | #6


    If your windows are made at low altitude and shipped to high altitude, and no special provisions were made for the change in air pressure, then two things will happen: the glass would bow outward, putting permanent stress on the glass and the seals, and your warranty would be voided. A reputable manufacturer would decline to sell you the windows! They'll fail early. Think cracked glass.

    Some European manufacturers will make the windows with an appropriate partial vacuum between the panes. Upon manufacture, the glass bows inward. Upon arrival at the site, they are flat. Properly done, the internal pressure between the panes matches the average air pressure at your site so there's no residual stress on the window. This service can add about $70 per triple pane window. The IGU may also require tempered glass on both sides, so more cost there as well. I've only read about this and talked to one manufacturer about doing this, no hands on experience with it.

  7. jackofalltrades777 | | #7

    So there are NO European triple pane manufacturers that will ship to a 5,000 foot elevation?

  8. GBA Editor
    Martin Holladay | | #8

    Q. "So there are NO European triple pane manufacturers that will ship to a 5,000 foot elevation?"

    A. I don't know the answer to your question. If you want to do your own research, you could call up distributors of any European window that you are interested in, and ask the rep for an answer to the question.

    Bill Dietze just wrote that some European manufacturers may be willing to ship windows to your location. But to be sure, you should ask a U.S. window rep.

  9. BillDietze | | #9

    Peter, didn't we have this discussion before? See The Zola rep seems quite happy to ship without breather tubes to well above 5,000 ft.

  10. jackofalltrades777 | | #10


    Zola responded that they will NOT take any orders UNDER $25,000 and there is a $5,000 shipping charge on top of that.

  11. BillDietze | | #11


    Well that's rude. My quotes went over that threshold so nobody brought up that detail. Sorry to hear it.

  12. lesse | | #12


    I have very bad experience with HEAT MIRROR film 193 of my IG glass panes gone concave because the sealant that Eastman recommends does not handel Krypton gas see the full problem on Eastman does not even react to my emails and ECO Insulating Glass Inc. does not want to take responsibility.

    1. jackofalltrades777 | | #13


      I can't speak about ECO Glass since I am not familiar with them and never used them. A lot depends on how the window is assembled. From what I read on your site link, the problem is more about the assembly techniques used rather than the actual heat mirror. Even poorly assembled dual pane windows can experience leakage and shattering.

      The company you referenced is based in Canada and you are based in the Netherlands?

  13. lesse | | #14

    Dear Peter,
    Thanks for your reply.

    I have had an engneer specialized in glass made up a report and his findings are clearly described in his report (in short with temperature changes the Krypton gas molecules get pushed out true the sealant but air molecules are bigger and can not get back in-between the panes with a result that the panes go concave inwards and and at a certain moment the glass can not hold the pressure anymore and implode this problem has already been described on-line in 1999) please have a look at the full report on:

    Eastman the supplier of the HEAT MIRROR film demands their clients to use a certain sealant question is did Eco Insulating Glass Inc. use that sealant? If so the sealant is no good to use with Krypton gas. These questions above i have asked in many emails to Eco Insulating Glass Inc. and Eastman but i do not get any answer at all.

    I live in The Netherlands where i build my passive home 10 years ago.
    I have used as much as possible the best green building materials in construction and insulation, energie is supplied by solar boiler, PV and CHP on natural gas.

    I ended up in Toronto to buy the 193 IG’s panes that i needed for my home. Eco Insulating Glass Inc. offered me QUAD SC75 with 2 layers of HEAT MIRROR filled with Krypton, at that time 2008 there was not a supplier in Europe for this type of insulating glass. (i personally visited the plant in Toronto to check out the company and met the owners)

  14. Deleted | | #15


    1. Deleted | | #16


      1. Deleted | | #17


        1. Deleted | | #18


  15. Deleted | | #19


    1. Deleted | | #20


    2. MelonyJ | | #21

      John, what was the feedback you received regarding the warranty. It looks like they provide a lifetime limited warranty. Just curious if you pursued that route and if so what the process was like?

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |