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Community and Q&A

Which type of interior storm window would you buy?

user-2310254 | Posted in Energy Efficiency and Durability on

My 12-year-old townhouse has builder-grade double hung windows. They are structurally sound but also fairly leaky. Instead of replacing them, I am considering installing interior storm windows.

A number of manufacturers offer these products. Most units are made with acrylic glazing, but one company uses clear vinyl. The vinyl-based product is much more affordable than the acrylic units (think $400 versus $40 per window).

Is it worthwhile to spend 10 times as much for the acrylic storm?

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  1. PeterGBADemo | | #1

    Hi Steve -

    Larson ( and Quanta ( have been in this industry for quite some time and make quality interior storms. They both make low-e storms, but exposed low-e generally means high solar heat gain more tuned to cold than mild or hot climates.

    There is also IndowWindow (

    I worked on the EfficientWindowCoverings website some years ago; take a look at the attachment selection tool there (

    Also, Lawrence Berkeley National Lab has been working on an energy modeling tool for window attachments, called AERCalc ( The tool includes storms.

    I have never worked with a vinyl interior storm.

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