Home Improvement Expert Danny Lipford

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Installing Window Film on Insulated Glass

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I’m considering putting a heat resistant film over my double pane windows but was told not to since it could blow the seals. Is this true? -Stephanie

Hi Stephanie,

Some window manufacturers do not recommend installing heat blocking window film on their insulated glass windows due to concerns that it could cause the inner pane of glass with the film to heat up more than the outer pane. This may result in the two panes of glass expanding at different rates, which could lead to a break in the seal between them or even crack the glass.

The larger the window, the greater the chance a problem could occur. Some types of window film cause less heat to build up than others, so check with the manufacturer to see which ones they recommend for insulated glass.

Also, be aware that applying heat blocking window film to insulated glass may void the warranty on your window, so be sure to check with the window manufacturer first. The warranty provided with some window films is meant to act as a replacement for the coverage that came with the window.

Danny



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4 Comments on “Installing Window Film on Insulated Glass”

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  1. charles Kuhn Says:
    May 31st, 2011 at 9:48 pm

    Your correct, I’ve been in the Window Business for 25 yrs and can’t begin to tell how many service issues I looked at for seal failures with film over glass. The heat builds up and breaks the seals around the metal spacer bar. Bottom-line it voids the warranty. Ok on single pane only.

  2. Robert Says:
    October 15th, 2011 at 12:18 pm

    There are a vast number of film varieties that are perfectly safe for application to dual-pane sealed window units that not only block a large amount of heat and 99% UV, but many are even barely noticeable and that DON’T VOID a window warranty. The issue of window failure and warranty issues occurs when an inexperienced or untrained window film installer applies an improper film (usually one that is too dark and retains too much heat). It is perfectly SAFE and NOT against warranty to install the CORRECT window film on an IG window unit.

  3. RICHARD LAMOUREUX Says:
    June 27th, 2012 at 12:54 pm

    We recently installed double glass windows to an office environment. Later we put dark tint on the inside of the windows hoping to keep it cool. Seems it had the opposite affect and instead of the temperature being lower it seemed that the double glass retained more heat and raised the office temperature. Almost everything I read suggest not tinting windows when they are double insulated due to warranties/etc. What I can seem to determine is it wise to put the tint on the inside or outside and what problems can develop?

  4. John Sortore Says:
    January 16th, 2014 at 2:41 pm

    If you read from the glass industry experts who deal with reality, you will discover that until the problem of “internal pressure equalization” is overcome, all insulated glass units will fail unless they are installed in “ideal climate conditions”. Even then, the effectiveness of the seal is questionable. The fact that all IGUs come with a desiccant inside should tell you something right off the bat. The main reason that it is even installed inside is to delay the discovery of condensation by absorbing it before it deposits itself on the glass. If the desiccant wasn’t in there, you would see condensation in the units much sooner – possibly soon enough to keep you within the warranty period.

    Most independent studies have shown that the energy savings from IGUs will never offset the cost of the purchase. The only viable solution (and the one that makes the most sense) is the installation of exterior storm windows. Check with the U.S. Dept. of Energy and see what they say about using storm windows. Does it seem odd that the only folks pushing the replacement window craze are the manufacturers of replacement windows?

    PVC is the worst idea that they have ever come up with, not to mention that their lower cost is NEVER passed on to the consumer thus profit margins on pvc windows are much greater than wood ones. You can make an awful lot of PVC in the time that it takes to grow a tree.

    I could go on and on but the bottom line is that weatherizing your current windows and adding good storm windows will save just as much energy but cost less than new windows. If you need new windows, installing storm windows will delay your new window purchase and give you time to save up funds and also do research to find the best window to use with your storm windows. If everything works right, you will be able to re-use your storm windows over your new windows which will allow your new windows to last longer.

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