Simple yet highly effective

Indow storm window inserts are made out of acrylic glazing and edged with our patented Compression Tube. The tubing compresses when pressed inside your window, holding the insert securely in place while sealing out cold drafts and hot air. The tight custom seal delivers superior performance.


Using flexible compression tubing

The tight seal between the Compression Tube and your window frame provides exceptional performance, keeping at bay cold drafts (or mitigating heat gain during the summer). Indow storm window inserts provide superior comfort no matter the weather or temperature outside.


50-70% Decrease in sound penetration

Hush noise so you can sleep and live comfortably. When placed over operable single-pane windows, Standard Grade inserts dampen noise by up to 10dBA, which equates to 50% noise reduction. Acoustic Grade inserts reduce noise through operable single-pane windows by up to 18.9 dBA, equivalent to a 70%+ reduction. When placed over operable double-pane windows, Acoustic Grade inserts reduce noise by up to 12 dBA, equivalent to more than a 50% reduction in noise and an STC rating of 42 to 45.* 

*Overall noise reduction performance depends on how much noise is coming through walls, ceilings, floors, and doors. You can download an independent STC testing report here

storm window inserts reduce noise better than replacement windows


Reduce energy use by 20%

A U.S. Department of Energy study found that installing Indow inserts led to a more than 20% reduction in heating, ventilating and air-conditioning use in a Seattle home.

A separate study by Portland State University’s Green Building Research Laboratory found similar results. Comparing gas usage before and after installing Indow inserts in four Portland-area homes, the laboratory found heating-energy costs were reduced by an average of 19%.

storm window inserts save up to 20% on energy bills



Indow window inserts have 94% of the insulation of standard double-pane windows. The surface of an acrylic Indow insert is much warmer than the surface of a pane of glass, so you’ll feel warmer even if the air temperature in both cases is the same.

** R Value measures the thermal resistance of a material and its effectiveness at keeping the outside out and the inside in.


Indow inserts + single-pane data provided through independent testing conducted by the US Department of Energy’s Pacific Northwest National Lab and Portland State University’s Green Building Research Lab. Actual performance will vary depending on condition of window.

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