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Standard Grade

What are Interior Storm Windows?

man installing interior window insert.

The Indow Standard Grade interior storm windows are an innovative, cost-effective way to block drafts and noise to make your home comfortable and energy efficient. We designed these inserts to help your existing windows perform like new double-panes all while blending into the frames so they’re nearly invisible. They install in seconds without disruption or mess.

interior storm windows or interior window inserts.

Unlike conventional interior storm windows, our indoor storm windows press inside your existing window frames without a damaging mounting bracket. Save money on energy bills while keeping your original windows to preserve your home’s character and value.

Standard grade custom indoor storm window inserts:

  • Nominal ⅛” thick acrylic glazing.

  • Edged in our patented silicone compression tubing.

  • Made in three different colors - warm white, brown and black.

  • Available in custom shapes like arches and rounds.

How Custom Storm Window Inserts Work

Because houses settle, most windows aren’t square. At Indow, we laser measure every window opening and then custom make each insert, ensuring a precise, snug fit for an airtight seal that blocks drafts. That compression is also what holds the insert in place.

The window inserts blend in and can’t be seen from the exterior of the house, so don’t violate historic district guidelines. People with newer double-pane windows use Indow inserts to enhance their performance.

Standard Grade inserts are suitable for any room. Some homeowners start by installing inside storm windows in their draftiest space and over time buy inserts for the rest of their home.

Testimonials on Custom Storm Window Inserts

Instead of replacing the historic windows in his home, Kester installed Indow Standard Grade interior storm window inserts. He immediately improved the performance of his windows.

“What attracted me to the Indow window insert product was that you don’t mess with your house at all. You just press the inserts into your window frames. There’s no mounting bracket. They’re fitted perfectly to each window so it’s just the pressure gasket that allows you to insert it into the window. They’re light and easy to install and remove again and again.”

For partners Greg and Eddie, using Standard Grade eliminated condensation in their mid-century modern Texas home. But Indow inserts are versatile. For a slightly higher price, our specialty grades offer an impressive array of solutions for the myriad challenges posed by windows whether it’s the need to block sunlight or UV rays or create privacy or quiet.

“I couldn’t be more pleased,” said Greg. “The Indow inserts have a very low profile.”

How Standard Grade Storm Window Inserts Perform:

  • Saves up to 20% on energy, whether winter heating bills or summer air conditioning.

  • 50 percent noise reduction (10-12 dBA) when placed over single-pane windows.*

  • Acoustic Grade is the best option for quieting outside noise and will achieve a 70 percent noise reduction (18.9 dBA) when placed over single-pane windows.

Explore complete performance data here.

What Do They Cost?

Consider the cost and disruption of replacing your windows. A vinyl window averages $66-$87/sf. A wood window averages $71-$109/sf. With Indow inserts averaging between $31-$44/sf MSRP, your window project can cost a fraction of other options.

Standard Grade

$31/sf or just $372 for an average window

Our workhorse interior storm window insert blocks drafts and reduces outside noise.

Performance Grade

$40/sf or just $480 for an average window

Our 4 options in performance grade inserts provide superior protection against noise and light.

Commercial Grade

$44/sf or just $588 for an average window

Industrial strength inserts with a scratch-resistant coating can be cleaned with common products.

When you measure your windows, you’ll have help at every step. First, we have a library of video and written tutorials available. Second, our amazing team is always ready to take your call if you need assistance. Third, our proprietary measurement software will automatically check your measurements as you enter them to ensure a tight, snug fit for your customer window inset.

*Sales tax & shipping charges not included. Shipping charges vary by region and order size – talk to a Fit Specialist to get our best pricing.

Data Driven Results

average percentage saved on heating & cooling bills

20%

30%

15%

INDOW

REPLACEMENT WINDOWS

*We want to ensure our inserts help solve your noise problem. Overall noise reduction depends on the amount of noise coming through your walls, ceilings, floors, doors, and existing windows. Noise reduction will be less when placed over double-pane windows. Read our full Noise Reduction Sheet to learn more.

Get a Free Estimate

bedroom with window with Indow inserts installed for soundproofing in San Francisco

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Fill out this form and one of our Comfort Experts will be in touch to prepare a specialized estimate for your space.

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Customer Reviews

Excellent

4.49 Average 1490 Reviews

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Jen F

Worth the money!

Posted 3 weeks 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 weeks ago

Anonymous

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

Posted 1 month 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 1 month 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 1 month 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 1 month ago

Susan A

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

Posted 1 month ago

Volodymyr R

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

Posted 1 month 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 1 month ago

Anonymous

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 1 month 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 1 month ago

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 1 month 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 2 months 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 months 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 2 months ago

Indow window insert compression tube color samples.

Customize Your Insert

Each insert has a tube that edges the clear acrylic. This tubing should blend into your window frame. It comes in three colors: white, brown, and black.

All our acrylic interior storm windows are durable, lightweight and made to blend seamlessly with the surrounding frame. Don't buy new windows. Make the ones you have just right with our precision measuring software, which will ensure a tight fit for your new window inserts. Just choose the grade you need and get started measuring. We're here to help at every step.