Transom Window Treatment

Pat Ruge
by Pat Ruge
5 Materials
5 Hours
Our West facing side of the house present special problems, especially when the temperatures reach 100+ degrees. These windows are all located in the kitchen/eating area and family room. In other words, where we want to be in the hottest time of the day. To address this problem, I decided on the following solution:
This particular window presented a special problem in that the shape is more difficult to work with. Although I have three other windows to deal with, my focus is on this one as it presents the most difficult issue as you will see later..My walls are 10' tall and these windows are facing directly West, which means they get the full sun at the hottest time of the day between 2-3 pm. Last week we had 100+ for seven days in a row. All of which makes it unbearable or causes me to run the AC excessively..My objective then is to produce a window cover which is both attractive and insulating from the heat.
Using an electric bread knife, I cut out the shape of the window, using the R-Tech 1 in. x 4 ft. x 8 ft. R-3.85 Insulating Sheathing and joining the three pieces with duct tape on both sides of the joints. One side of the sheathing is covered with an aluminum shield and this side will face the outdoors to help reflect the heat. The aluminum side will be facing outwards to help reflect the sun..This sheathing does come in 1 1/2" and 2" thickness. In retrospect, it might have been better, if I had chosen a thicker insulation. We shall see...
Cut quilt batting exactly to match the shape.
Pull back a portion the batting and spread ModPodge (this is my own recipe) before laying back the batting. I just poured it on and spread it out.
From the opposite side, I roll back the batting and continue to ModPodge and lay down the batting till complete. .It is important to note that not every glue will work here. Any adhesive which has a petroleum base will cause the Styrofoam to disintegrate. Do not use a spray adhesive at this stage of the project. I learned that lesson the hard way, tested several products and determined ModPodge is the best solution.
The fabric I have was cut into three pieces in order to accommodate the width. I match up the pattern as best as I can.
I then lay a bead of hot glue to join the pieces together and help secure it together for installation purposes.
Because I am now securing the batting to the fabric, I can use the spray adhesive. Fold back 1/3rd, spray both batting and fabric and the carefully smooth it back into place and working out in wrinkles.
Roll back the remaining 2/3rds and continue to spray adhesive and fabric to smooth each section, until complete. Ready to install. The loose edges will be addressed during the installation.
Press the entire cover into the window space and using the putty knife, push in the excess fabric until all edges disappear. My cuts were not perfect on the shape and it left some small gaps. I stuffed the gaps with loose batting until the gaps were filled. This was done to insure there would be no beams of light shining through.
I could have applied some hot glue at various points, however, the fit is so tight I don't believe it necessary. I wanted to leave it so that if I ever decide to change the fabric, it would be easy enough to remove.
This shows two other windows done. This shape, of course was much easier to do.
The last window above the door, completes the project..I believe this window treatment will do well in winter as well as summer.

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Suggested materials:
  • R-Tech 1 in. x 4 ft. x 8 ft. R-3.85 Insulating Sheathing   (Home Depot)
  • Fabric   (Pre-owned or Amazon)
  • Quilt batting   (Joanns or Amazon)
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Frequently asked questions
Have a question about this project?
3 of 8 questions
  • Vicki Vicki on Sep 24, 2017

    Was there anything else you used to secure this to the window, or is it simply wedged in holding itself within the framing? I'm planning on making insulating window covers for my RV and I'm not sure how I will hold them in yet. If you have any suggestions I'm open to suggestion. Thank you!

  • Christy Roppel Christy Roppel on Nov 02, 2017

    Hi! It's lovely! I'm just wondering: does it look "trashy" from the outside?


  • Pamela Harper Pamela Harper on Aug 31, 2018

    What does it look like from the outside. Can you provide a picture please. Thanks love this idea.

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2 of 47 comments
  • Pat Ruge Pat Ruge on Nov 16, 2017

    Depending on where you are in the country, assuming PA, the West facing windows will absorb the afternoon sun. In some cases that can be a good thing. In the south, it can be extreme, as in my case. In the North, it can be a good thing, if heat is what you are looking for. I chose to block as much as possible for when temp approach 110+ it is unbearable. Keep in mind, that my house has about 15 transom windows and enough light is not the problem - heat is the problem.

  • Dee Dee on Jul 08, 2022

    This is a problem with transom windows in all areas that are hot. I did the same on my front door with that kind of window. Mine were more subdued and made them blend in. I also made sure the outside and inside were done, so there were no trashy sides. It was a job but I too used home made modpodge. Spray glue was horrible.

    You gave great instructions