We have so many happy customers that love their custom window inserts!
Check out some of our recent reviews and see our products in use.
Find your perfect window insert for your home!
Customer Reviews
Overall rating: 4.9 / 5 from 2799 reviews.
High quality product with outstanding customer service. Everyone was so helpful and polite, even when the product did not fit due to my error it was replaced for free. I would recommend this product and company to anyone who would listen.
Very nice, it was very snug getting a/c unit to pop in and it was a hair short. I made it work.
Great quality! Super easy process for sizing and it fits great! Going to order another one for our second AC unit!
This custom-fit acrylic panel has been flawless for venting my Midea Duo 12,000 BTU portable AC through a casement window. It arrived fast, and fit like a glove. It sits in my window frame with absolutely zero gaps. It holds up beautifully against the intense summer heat while the AC works wonders cooling down my entire 3-car garage. If you need a clean venting solution for a casement window, don't waste your time with DIYing it. This custom panel is worth every penny due to its professional look. I highly recommend Martinson Manufacturing!
The fit is good and the Nano Tape really holds the insert securely. I do like that I can still close the awning window during the hot part of the day.
Highly recommend and wish I found you sooner!! The glass fit perfectly as does the ac hose! I now have AC in a room that I had no way of using. Great product and quality.
Marie was incredibly patient and helpful. I was so concerned about proper fit, but with her guidance, it was assured. Great personal service!
Custom Portable AC Sliding Window Vent Kit for Windows & Doors
Thank you Martinson Manufacturing. We are very happy with the plexiglass you designed for us. It fits perfectly and is very secure. We recommend this for anyone with casement windows. You were so easy to work with. Our order was completed in 3 days. Thank you for your great service Luanne 7-1-2026
An Engineering Marvel — Believe the Reviews! The reviews don't lie — this thing is every bit as good as everyone says. The price made me hesitate, but I threw caution to the wind and bought two. Zero regrets. I was so tired of MacGyver-ing my own adaptation (see photo of my "handiwork" — LOL), and this kit made all that DIY struggle a distant memory. My favorite part? The hose looks like it's floating in mid-air. Pure magic. And can we talk about the packaging? Hands down the best-packaged product I've ever received. Funny moment: I pulled out the "windows" and thought, wait, I didn't order brown! Turns out it was just the protective covering. They ship it as well as they build it — and that's saying something. Well done! — Julie
Perfect fit. Customer service is very good . I recommend it
Love, love, love this window insert! Having used the kits that come with the ac units which are a nightmare, the window insert from Martinson Manufacturing is a dream! If you use a portable ac unit, we highly recommend you get one of these window inserts. You will not regret it!
Custom Portable AC Sliding Window Vent Kit for Windows & Doors
It fits snugly and looks fantastic. It also arrived very promptly: thank you!
The quality of the window panel is so much better than I could have hoped for it fits perfectly. I used the adhesive tabs to keep it in place. I highly recommend anyone who has an awning type window to purchase your product. And it came in just a few days thank you again for exceeding my expectations.
At first I thought it was too much money - but I was wrong. I love the window and it’s worth every penny! The various videos on correct measurements helped a novice like me get it correct. I’m glad great companies with exceptional customer service still exist.
Not only a great solution, this is a well made, high quality product that was packaged properly too. We are delighted with the product and purchasing a second one. Truly high quality.
This is great fits perfectly and was pretty easy to install love its like still having the window in
Works beautifully!! I only have this one window in my apartment, and I didn't want to sacrifice the natural light with one of the other vent methods. This was the perfect solution!! Took some wiggling and putting foam around the edges for a good seal, totally worth it!!
Great solution, I would say only clean design solution on the market for portable AC. Keep up the good work, stay safe and healthy
Love it. They look so nice!
Custom Portable AC Window Insert for Single & Double Hung Windows
The installation was easy and went as expected. A perfect solution to having casement windows. FYI, I also wrote a review on the Walmart web site for the Midea A/C unit I purchased and recommended your casement window insert. Thank you!
This item is fantastic! The cut out for the vent is perfect. Installing the plexiglass was relatively simple and it looks great. This is definitely a more pricey solution than some of the other products out there but it is worth the extra expense.
After a few summers of hooking up our portable AC with all kinds of strange solutions, finally sprang for one of these kits. The measurement and installation videos were super helpful. We have original wood crank out windows from the 1980s, and so in my case the measurements were a fraction of an inch wrong even though I followed the instructions, because my window screens fit into a little gap in the old wood frame, and are actually a bit wider than the plexiglass needed to be cut. However, just a little bit of carefully sanding down the plexiglass and they fit right in. Not a fault of Martinson, we just have strange windows. Since our wood frames are old and not 100% straight, after popping in the kit, I also added some sealing foam tape and jammed some extra foam into the cracks just to make sure I had a good seal. But, for most folks I'd imagine this would not be necessary. So a little bit of extra work for my strange old windows to pop this in and seal it, but well worth it! Now we're all set up for the hot part of the summer with a great looking frame that doesn't block our view. Love it.
Perfect fit. Good packaging for the shipment. Very happy with the product. Only suggestion - come up with a better installation tool for the push pins. Kind fo goofy balancing that pin on the tool before rocking it in place. It worked, but I think you can do better. Overall, nice job - and thank you.
Perfect fit and it’s very solid.
Great fit. Delivery was quick. Looks amazing. I tried the alternatives that are available at the hardware stores. This looks and works so much better.
Fit great. Looks great. I’m happy
The picture does not do it justice. It looks great, easy to install, and is effective. The delivery was quick. The company was lovely to work with..they answer any question or concern that I had. Now in 30 degree weather in BC I am so glad I made the decision to invest in their product.
It’s an absolute perfect fit for my window. I was highly impressed and very pleased. I definitely made a good choice with this.
Window arrived in very quick fashion and was easy to install. Packaging was top notch and there were no issues with the install. We purchased a new Air Conditioner, so we had a bunch or parts left over from the new AC unit. We figured out that these were for install on a up and down window instead of the the casement window. We installed with all of the plastic tape strips since we have windows that were made with acrylic. If we ever decide to take out the unit and re-install the screen we will probably need more plastic tape for the next time.
What an amazing solution to the one very hot, sun-baked room in our home that always struggles to remain cool. We searched all over for the best and most practical fix with our casement windows and this was it! The ordering process and the helpful videos were phenomenal and helpful. Shipping was very fast, the fit was absolutely perfect and the insert is clear as any high quality window could be. We are so happy. Thank you!
To be clear, the issue here is cost/benefit ratio. I needed to install a Midea portable AC in my elderly parent’s appartement equipped with casement windows. Measurements were based on screen size and pictures of the window frames (we’re in different cities). I installed these today and could not be happier. Fit and quality are excellent. TBC, this is expensive but worth the expense. As the pictures indicate, this is a narrow window so the insert hole is sideways and the Midea Sliding Window Adapter is required. As previously mentioned, the Martinson round bug screen cannot be installed since the sliding window adapter won’t fit (the crescent-shaped one is fine), and the Midea Air Divider part for the Sliding Window Adapter won’t allow you to close the window. This being said, I’d like some type of rebate for multiple orders.
I’ve been so pleased with their service that this is my third order. Cut exactly to specs and extremely well packaged. I’ve had several with cutouts for solar panel wires that worked perfectly.
Custom Portable AC Sliding Window Vent Kit for Windows & Doors
Perfect fit, great product.
I would highly recommend this company for anyone with casement windows. I ordered two for my home and I am very pleased with the results. The company is very responsive. They emailed me right back about a change to my order and were able to make the update prior to manufacturing. My order arrived within a week of purchase!
Easy to install well-made product
With my tilt-in window, I wasn’t sure that this insert would be an option for me. The team at Martinson was so incredibly helpful. After a call and several emails, I was able to place an order and have everything installed within days. Packing was protective and professional. Thank you very much!
Perfect fit!!!
Very nice product - easy to install, fits perfectly and works well with our air conditioning units. I wish our screens they replaced were made with this much care and attention. Highly recommend.
Amazing how easy it was from start to finish! I measured and picked out where I want the openings (left, middle or right side). Then once received in the mail all I did was take screen out and replaced it with the plexiglass and secured it with the provided stickies. Amazing! So secure and best looking! Highly recommend!!!
We love this company! We have two of these panels and they have been a game changer and they're so well made and timely in delivery. I never write customer reviews but this company deserves it for quality.
