Arched Windows? We’ve Got You Covered.

Specialty shape inserts for the arched, round and otherwise odd-shaped window.

Acrylic opens up all kinds of possibilities. It’s lightweight, more transparent than glass and can be made into just about any shape imaginable. Which is why people with odd-shaped windows, from arched windows to those resembling batwings, have sought us out to make them interior storms.

Often people with unusually-shaped windows didn’t think they were ever going to be able to block drafts on that funky little round window on the second-floor landing.

And then they found us.

How To Get A Custom Specialty Shape Window Insert

First we'll help you determine if inserts are the best solution for you. Next, we'll guide you step-by-step through measuring & tracing your odd-shaped windows and then custom-cut your inserts for a perfect fit. Get a free estimate today to discuss pricing and begin your order!

odd shaped windows

How do we make custom-shaped window inserts?

We ask people to make a template by tracing their window onto paper. Tyvek is the best, because it’s strong and light still shows through. On occasion, people will trace their odd-shaped windows onto tissue paper, but that’s prone to ripping. We don’t always need a template. Every window is different – we just try to keep the process as simple as possible.

Here’s a picture of our Operations Manager Brianna, reviewing some window templates on our conference room floor.

woman drawing odd shaped windows

After we trace the shape onto acrylic, we use a circular hand saw to cut it.

The circular saw cuts in small straight lines, kind of faceting it a little like a diamond. Then we sand that edge smooth, forming it into an arch or round, or the dips and peak of a window that resembles a fancy badge.

This is a big departure from most of the inserts we make. For normal rectangular window inserts, we input measurements into a software program that tells our Computer Numeric Control (CNC) machine how to cut the acrylic.

Also, for normal, rectangular window inserts, we use a rigid ABS (Acrylonitrile Butadiene Styrene) plastic carrier with a silicone edge. But that won’t work for shapes that dip, peak, half-round and full circle!

For custom-shaped funky windows, we have to use pure silicone tubing all around the edge, like we used to for all inserts in the old days (which was just a few years ago!) It bends and molds nicely to the edge of round window inserts.

Some other shapes we can make inserts for:

  • Half-round
  • Oval
  • Gothic
  • Eyebrow
  • Bell-top

Indow vs. other odd-shaped window solutions

It’s hard to find companies that make exterior or interior storms for odd-shaped windows. It’s labor-intensive to craft them of metal or wood, which makes them expensive. Plus, they’re hard to remove and put in.

“People are just generally surprised to find we do it at all,” said Brianna. “A lot of companies don’t. People tend to be surprised by how nicely they fit. They disappear into the frame.”

odd shaped windows

Have a funky window? We would love to see it! Share with us on social media on Facebook, Instagram or Twitter.

To see some great Indow customs, check out our Bowdoin case study.

Oh, and did we mention that these odd-shaped windows come in all our grade types, from Privacy to our UV-blocking Museum Grade? Check out our product pages to customize your order.

We’re happy to discuss your odd-shaped windows! Contact us here.

Customer Reviews


4.49 Average 1477 Reviews logo

Matthew L

Indow inserts were easy to measure, order and install. They've provided great insulation for old single-pane and stained glass windows in an antique home. We can significantly feel how much better the home holds heat.

Posted 2 days ago

Ellis W

I ordered two Indow inserts for my home. They are doing a great job, entirely happy with them and the ordering process.

Posted 1 week ago

Elizabeth W

I can't say enough good things about this product and company. Our house is 101 years old and the sidelites next to our front door are single pane ancient wavy glass which means when it gets very cold (Chicago temps) we can have an inch of frost covering the INSIDE of our windows. I was desperately searching for a solution so our front vestibule was not so cold and a friend recommended Indow. The process could not have been simpler and the temperature difference it has made is off the charts.

Posted 2 weeks ago

Austin T

I have several historic single pane gridwork mullion windows. They're beautiful but have almost no thermal protection. Indows proved to be the perfect solution to preserve these windows while getting the thermal comfort we need. They were easy to install and work perfectly!

Posted 3 weeks ago

Kathryn M

Amazingly easy to install even the safety chain holders. I. Noticed an immediate sound level difference and the room atmosphere became more solid feeling and pleasant. They also gave an insulating feature to the window drafts are non existent! The house is 50ft off a State highway that is heavily traveled in warmer months I'm confident the indows will handle it. I'm very pleased!

Posted 1 month ago


We ordered the acoustic inserts to help with road noise, and we've been sleeping so much better with them!

Posted 1 month ago

Sienna K

We used the windows inserts in our skylight. They are great! They the horrible drafts and noise out and were cost efficient. My only comment would be to provide better measurement and installation instructions for skylights specifically. It took us a lot of guessing and research to measure and install because skylight directions were not provided and the windows install guide doesn't always apply to skylights. Other than that though great product and I would buy again!

Posted 1 month ago

ted t

Our home was built in the late 1800s and we have spent a lot of money over the last 20+years restoring it.We did not want to replace the windows with modern windows because of the cost and originality. But the single pane windows come with a price also. the main reason we purchased the Indow window inserts is because of the condensation on the inside of the windows.We would literally have a take a towel and wipe them down every morning in the winter. There would be a puddle on the sill,and wood and water dont get along to well. SO we looked into the best solution to our problem and found Indow. Was reluctant to spend that much money but am super glad we did!! They have been installed now for over two months and our condensation problem has been virtually eliminated.!!! AND our furnace does not run as much as it did before. Over all it was money well spent!! The process was a little scary at first but they have a simple formula. And our contact person,Reed was awesome. Answered any questions i had and was always available.

Posted 1 month ago


Used to block interior side of a garden window in the the kitchen. Without insert, cold air literally poured into the kitchen making a winter jacket almost mandatory when preparing meals or washing dishes

Posted 1 month ago

Rob S

Highly recommend! The team (Brian) took time to help me figure out the best solution. They were made and delivered faster than expected. It was very rewarding to install them because I could feel the cold air get squeezed out as they went flush against the single pane of glass. Solid quality and great fit.

Posted 1 month ago

Alexa L

My inserts fit beautifully into my 125 year old windows - many of which were 5 feet tall. Easy to unwrap and install. Great product and even better service! I liked the process of measuring the windows with a laser measuring tool which was easy to use and precise. The product came in good condition after shipping across country and was well marked. The customer support was excellent.

Posted 1 month ago

Sarah D

Received our Indow Windows and can tell they are blocking a lot of the noise we could hear. Right now the weather is mild, but hoping to notice a big difference when the summer heats up. Our house is in a historic district and we cannot change our windows. They are very drafty and thin glass. We only ordered two, but we are in the process of ordering for four more. Love that we don’t need to drill holes or anything and they just pop right in.

Posted 1 month ago

Allan F

Every thing arrived in perfect condition, thanks to the very secure packaging. Windows fit as expected, although quite tight. After installation we noticed that the cold drafts were gone and the room felt a lot warmer. We are very satisfied with the product and the result.

Posted 1 month ago

Adriana W

Great customer service! Super satisfied with our windows.

Posted 1 month ago

Thomas M

Indow service and product is good. Reduced outside noise considerably.

Posted 2 months ago