Magnetic Seal vs Compression Seal

What difference is a particular window attachment going to make to the comfort of your home? How effective is a magnetic seal or compression seal when used on a storm window? We’ll answer these questions in this blog and why Indow decided against magnetic window insulation.

Why We Said No to Magnetic Seal

When Indow first designed our window inserts, we considered putting magnets inside our compression tube, but we found that a magnetic window insulation created a lot of design flaws.

“It’s not very attractive, it’s cumbersome to install, and that metal frame remains in your window frame after you remove the insert and that’s ugly. So there were three things we didn’t like about the magnetic system.”

-Sam Pardue, Indow Founder

First, for a magnetic seal to form, magnets have to grab hold of something. That something is permanently attached to your window frame—generally a metal bracket fixed to the entire window frame needing many holes drilled into it. So it’s cumbersome to install.

Second, magnetic window insulation is not attractive either with the window insert installed or removed. If you take the window insert off, you still have a big metal bracket surrounding your window.

diagram of a magnetic window insulation system

Third, the acrylic used in most window inserts expands and contracts with the temperature. While the window insert and attached magnets move, the metal frame does not. So, whatever magnetic seal there was is broken and the whole panel can pop off.

Magnets attract in one direction, but compression tube creates spring force all the way around the window frame. It absorbs expansion and contraction in every direction and creates friction and resistance against air pressure.

So, we removed the magnet and created a window insert that relies on compression seal alone. The compression tube can do everything we need and the simplest solution is often the best solution.

woman installing Indow insert in window to create compression seal

Why Compression Seal is Better Than Magnetic Seal

The compression tube around our acrylic panels is the spring force that holds in insert in place. It absorbs all thermal expansion caused by temperature change. This ability to expand and contract creates a near airtight seal no matter the shape, size, or condition of your window. The compression tube is a seal against drafts and heat, and it keeps conditioned air inside.

close up of Indow window insert creating compression seal

A compression seal is stronger than a magnetic seal because it is better at dealing with out of square windows. If your home is older and has had time to settle, it most likely hasn’t settled perfectly straight – this causes out of square windows.

“The problem is that magnetic systems don’t always deal really easily with the fact that most window frames are really out of square. So sometimes you get a gap up in the corner, if it’s a really out of square window. With our system we’re going to make the insert the exact shape of the window opening, you’re going to get very tight seal all the way around—a nice even compression.”

– Sam Pardue, Indow Founder

Magnetic seals can get gaps because they were made for a perfectly square window frame. Compression seal adjusts for the out of square window so you continue to have a tight seal and even compression.

Our compression seal can accommodate expansion and contraction from heat and window frame inconsistencies without altering the window at all. Our compression seal is stronger than magnetic seal, fits any shape of window, and requires no hardware.

For more information read about our compression system.

Customer Reviews


4.49 Average 1494 Reviews logo

Paula S

From start to finish, we were very pleased with our rep, Reed, and the other staff at the PDX will call! The inserts themselves are stupendous! We purchased six total for the noisiest, road side(s) of our home. The outcome was beyond our expectations! Not only did the three rooms that bordered the road become at least 70% quieter, the other end of our home did as well! I cannot recommend Indow inserts more! The technology makes sense to add the inserts rather than purchasing new windows. Great results and thank you! Paul and Paula Spilsbury

Posted 4 weeks ago


Brian was very helpful & informative. He helped me order the correct windows for my needs. They were shipped with the utmost of care & arrived ahead of schedule. Ultimately, the Indow Windows have been very helpful in muffling unwanted noises & they have helped save on our energy costs. Thank you, Indow Window!

Posted 1 month ago

Cynthia M

Very happy with the reduction in noise. Easy to install and use. Great customer service.

Posted 2 months ago

Juli E

We are thrilled with our Indow window inserts! I'd been on the lookout for a more permanent solution to leaky windows in our third floor living space. I discovered Indow on social media but since then have learned of friends who'd had Indow recommended to them by their rennovation contractor. The entire process went smoothly with friendly reps at hand to talk through questions during measuring, etc. They fit perfectly and help us to maintain the beautiful design of the windows on our 100 year old home! Highly recommend!!

Posted 3 months ago

Jen F

Worth the money!

Posted 3 months ago

Elizabeth H

For townhouse living, this solved my problem with noise from my neighbor's with my kitchen window. A considerable decrease of noise indeed! Measurements were a bit frustrating so I recommend using a laser measurement device and following directions to use a string for the diagonal. They look great and were easy to push into place. I highly recommend as an alternative to buying a new window.

Posted 4 months ago


Easy to install, and instantly stopped drafts and dampened outside noises very effectively!

Posted 4 months ago

Robert C

The process could've been smoother with the sending of the measuring kit. There was a delay with weather in Oregon but then it felt like my kit was still delayed due to other reasons. Most new homes (like mine) have textured paint and it can also be inside your window frames. I measured everything out but I still have little tiny gaps due to the texturing. Not indows problem but just be aware you made need to sand or fill in those gaps yourself to get a perfect seal. I did the acoustic grade inserts and they have reduced some noise but they will not completely block or significantly reduce road noise. This is most apparent with deep or lower frequencies like truck exhausts or modified street racing cars that are quite popular these days. Taking the inserts out to open your windows isn't an easy task. The little metal hook they provide needs to be either bigger or you can attach something to it as a way to leverage yourself. Overall the process was average. I think they're definitely a good option for weatherproofing and some sound reduction depending on the type of windows you have. I would purchase again.

Posted 4 months ago

Shelley C

The process for ordering and installing the Indow Widnow inserts was so easy. They sent the measuring information and it had great instructions. The inserts were delivered by UPS was crushed on one corner, but the company had packed them well, so there was no damage. We installed them the same day. It works best if you have two people completing the installation. We felt the results immediately and are glad we spent the money to make our home just a little more efficient.

Posted 4 months ago

Barry B

The insert fits like a glove and insulates the window! No more frost and condensation on the interior of the window! Thank you for an easy, effective and attractive fix!

Posted 4 months ago

Susan A

The support during the entire process was wonderful, thank you so much for the extra quiet space!

Posted 4 months ago

Volodymyr R

Very good good quality. Overall very satisfied with this product and service. Thanks

Posted 4 months ago

Jane H

Our home was built in 1913 and has beautiful old wavy glass single-paned windows. I’m so glad we were told about Indows and didn’t have to replace the original windows. We live in Canada but had no difficulty placing the order and were very impressed by how accurately the company met its deadlines, including cross border delivery. The Indows inserts blend in perfectly with our home and the existing window frames. You don’t see them unless you’re actually looking for them. But what we did notice was how much warmer the rooms feel the minute the inserts were installed! I can’t speak to any heating bill savings because they just went in this week, but our home feels much, much cozier. Our contractor who took all the measurements and installed the Indows says: “Excellent instructional videos: clear and informative. Very impressed with the design and the product. Overall, the ease of installation is quite impressive. Working with all the staff at the company was great – everyone was very helpful.” I’m already recommending this company to any of my friends who live in drafty older homes and want to reduce their heating/cooling bills and do some good for the environment.

Posted 5 months ago


Don't be afraid of buying an older home with single pane windows. This company has you covered. Their inserts are super high quality and fit well thanks to the laser measuring kit they send. Highly recommended!

Posted 5 months ago

Katie M

We purchased three Indows to reduce drafts and noise in our bedroom, which faces the street. The improvement was immediate. Our house was built in 1958 and although we have exterior storm windows we didn't want to replace the windows outright due to cost and architectural consistency. These were an excellent solution.

Posted 5 months ago