We use compression seals for windows because it’s simply the best way to seal against drafts and noise. The silicone in our compression system stands up to heat and sun while nearly disappearing into the window frame. It was designed with a refrigerator magnetic seal in mind, but improved and simplified to make it stronger and easier to remove and reinstall.


Here’s how we did it:

We use acrylic panels surrounded by silicone tubing to create our one of a kind window inserts. We use acrylic because it’s better for thermal and sound control than glass. We use silicone because it’s the best quality: long-lasting and resilient so it won’t lose its spring force over time. 

The Ove Glove uses silicone so that you can put your hands in the oven, protected, and the glove will not be altered by heat. The same is true for the silicone in your window insert frames. They’ll be exposed to sun, heat, and UV rays for years, but will ever change shape or lose their compression force.


“Silicone is almost impervious to UV radiation which exists in abundance in window frames, it’s highly resistant so it’s not going to lose its spring force over time. There’s something in engineering called compression set which is how much something loses its spring force when it’s squeezed for a long time and silicone has the very best compression set properties and durability properties.” -Sam Pardue, Indow Founder


Founder and CEO Sam Pardue installing one of the first Indow inserts sold,
in the first year of the company’s history


We’ve continued to innovate the compression seals for windows over time. We added more compressive range to absorb any variations in the window frame. For added resistance to air pressure, we increased the amount of spring force over the widest range of compression.

We even added a secondary hole in the tube as an option for large inserts to add a metal spine for stability. We’re constantly optimizing different aspects of our window insert from compression seals for windows to customer usability.

Evolution of the Compression Seal for Windows

We originally had a magnet inside our tube. We were trying to improve the magnetic attachment system by accommodating for the acrylic panel’s thermal expansion and contraction. We also wanted to clean up the appearance by removing the need for a big metal frame on the window.

The plan was to make the frame of the insert act like a refrigerator magnetic seal. If you look at a refrigerator door, it’s a magnet surrounded by a compression tube. So, we were going to combine a magnet and compression tubing, just like a refrigerator magnetic seal.


VP of Marketing, Kristina Damschen Spina, installing the insert in the kitchen where the product was invented.


The initial prototype ended up failing. And it didn’t look as elegant as we wanted. So we removed the magnet and just used the spring force of the compression tubing. It worked! And it looked so pristine in the window frame, you could hardly see it. We accomplished everything we wanted: a near airtight seal, a near perfect appearance, and no harm done to the window.


We continuously improve our compression seal for windows to create the best draft- and noise-blocking window inserts possible. Together acrylic and silicone forge a perfect sound and climate control combination. They are both resilient, standing up to sun exposure without losing their effectiveness. 

No matter what window issue you have, there is a window insert that can help. Take a look at all of our products to see what works for your situation.