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 1423 Reviews logo

Charles T

Working with Indow has been a great experience from start to finish. They answered all our questions & guided us through the whole process. We ordered 15 inserts & they have reduced the Highway noise that we were experiencing after buying our house. A great product & innovative company.

Posted 1 day ago

Sue W

I live 20 feet from a busy road with lots of trucks. We almost didn't buy the house because of the noise. my house is the perfect candidate for indows. After installing them (myself. .. directions were so easy) we can barely hear any trucks noise at all. Indies live up to their claim and has made a huge difference.

Posted 2 days ago

Richard H

I am very pleased with the noise reduction and heat-trapping effects of my Indow inserts. I bought three small inserts as an experiment for the noisiest part of the house all year round, and where it's cold in winter. They have done beautifully well in sealing out both noise and heat. My only issue has been to get one of them installed perfectly straightly on one side, but it was done in a difficult location and isn't that important. They are also quiet expensive, but I may get a federal tax rebate on them.

Posted 6 days ago

Hee D

It could have been better if the pallet was collected after the delivery. Also the inserts are more beneficial for picture/fixed windows rather than open windows. The price of insert are expensive.

Posted 1 week ago

Larry S

I was pleasantly surprised how well the appearance after installation, perfectly clear, plus reduce the noise from the outside more than I expected. I would definitely recommend anyone looking for noise reduction to consider these. I will be purchasing more as time goes on, thank you Indow

Posted 1 week ago


Called about price $1000.00 For 2 small windows asked about energy savings? They said no guarantees depending on location and almost other factors, why would I spend that money w no guarantees

Posted 1 week ago

Christie R

It has cut down noise tremendously and is definitely more efficient with keeping our cooling in and heat out this summer.

Posted 1 week ago

William U

Indow is a trendsetter in eCommerce. They make the entire process of ordering, purchasing, and installing their product very easy for any walk of life; and, their communication processes are excellent. The inserts I purchased and installed were just as described. They are effectively blocking soundwaves, but not vibration, which was discussed during my initial call with an Indow Representative. I would recommend Indow window inserts to a friend.

Posted 1 week ago


Our window inserts have decreased road noise in our bedroom by 75 percent which we are very pleased with. The whole process was extremely simple and organized. Everyone we dealt with was professional and helpful. The inserts were simple to install and I would recommend to others.

Posted 2 weeks ago

Jeanne S

They make it easy to measure and install and it does reduce the noise as I live next to a busy highway. I am happy with the purchase.

Posted 3 weeks ago

Ivan L

We have a multi-story building construction next block that starts at 7 a.m. daily and a busy street a few blocks away. Before the insert was in place in our bedroom, we heard every piece of construction equipment there, including the obnoxious beeps from vehicles backing down in the lot, and all of the emergency vehicles passing by on the avenue. Now, this sounds like something happening twenty blocks away, barely noticeable. This is a huge quality-of-life improvement from day one of the insert installation.

Posted 3 weeks ago

Stan B

All fit as planned and are good

Posted 3 weeks ago

Cassie M

Overall very easy process from ordering to install. Was just hoping that the sound dampening would have been a little better.

Posted 3 weeks ago

Dan C

Effective and frequent communication from Indo Window starting with the order process, through production and post-delivery. The insert fit was excellent, fitting snuggly. The panel is quite effective in reducing noise. My wife was sleeping in the basement due to traffic noise. She is able to sleep in her bedroom again. Overall an excellent experience!

Posted 1 month ago

Lynett P

Great product. Arrived a bit dirty.

Posted 1 month ago