Indow INTERIOR Window Inserts

THE BEST WAY TO INSULATE WINDOWS - Custom fit means great performance

Indow 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, hot air, and outside noise. The tight seal delivers superior performance and ease of use, making our window inserts an excellent way to insulate your windows.

How They Work

Indow Windows are window inserts made out of acrylic glazing and edged with a 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 energy and sound performance at a fraction of the cost.

how they perform

Indow window inserts give you energy-saving insulation equivalent to double-pane windows, and they're even better at insulating sound. Plus, you don't have to worry about any lead contamination that can occur when your old windows are ripped out of the walls.

how they fit

Each Indow window insert is laser-measured and custom made to fit your window precisely, making them easier to use than storm windows. Read more about product options and our laser tailoring system.


Flexible compression tubing creates tight seal

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

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50-70% Decrease in noise penetrating windows

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 Gradeinserts 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.* 

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Reduce energy use by up to 20%

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

Another separate study by Portland State University’s Green Building Research Lab found similar results from the use of our indoor storm windows. Comparing gas usage before and after installing Indow window inserts in four Portland-area homes, the lab found heating-energy costs were reduced by an average of 19%. 

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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. Increasing the surface temperature of your window space leads to increasing the mean radiant room temperature. This allows you to keep your thermostat at a lower level for ever further increased savings. Read more about this study from the Green Building Lab.

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

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