We just had Indows installed around the front door in our 210-yr old house. Amazed that they are completely inconspicuous and allow the charm of our antique glass to shine through the added layer of insulation!
— Dennis Petit

how they work

Indow window inserts are made of acrylic and edged with a patented Compression Tube. When pressed into place, the silicone tubing compresses, holding the Indow insert securely in place while sealing out cold drafts or hot summer air.

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.


Using flexible compression tubing

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

Performance Graph



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.

R-value performance graph.


50-70% Decrease in sound penetration

Indow storm window inserts offer remarkable sound reduction. When placed over an operable single-pane window, Standard Indow window inserts dampen noise by up to 10dBA, which equates to a 50% noise reduction. Acoustic Grade inserts reduce noise by up to 18.9 dBA, equivalent to a 70%+ reduction. Hush the sounds of traffic, planes and early-morning garbage collection so you can sleep and live comfortably.

Noise performance graph.


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%.

Energy use graph.

Image of special geometry window.

all Geometry

Indow window inserts can be customized to just about any shape - rounds, arches, octagons, batwings, odd angles, rounded corners or frames with multiple angles.

Image of laser measuring.

Laser tailoring

To ensure great performance and aesthetics, we use an innovative laser tailoring process to produce a great fit every time.

Image of standard grade Indow.

Specialty Grades

Seven specialty grades and three tubing colors are available. All grades provide the same draft blocking and noise reducing window benefits.

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Contact us for a free Indow® window quote.

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