Cat Door Window Insert

(17 customer reviews)


Endura Flap Thermo-Sash 3e™ Sash Window Cat Doors Include:

  • Durable and insulating cat door for windows with a single pane, LoE glass, and sturdy aluminum framing
  • Various flap sizes, colors, and adjustment ranges to fit your pet and your window
  • No tools are required to install window pet door inserts
  • Perfect for renters and vacation homes

Cat Door Window Insert Options

Additional information

Width Adjustment Range

22 in. – 25 in., 25 in. – 28 in., 28 in. – 31 in., 31 in. – 34 in., 34 in. – 37 in., 37 in. – 40 in., 40 in. – 43 in.


Cat door window inserts from Pet Door Products are a great way to give your pet the freedom to come and go as they please, while also keeping out unwanted guests.

What are the Benefits of Using a Cat Door Window Insert?

Take a look at these key advantages of installing a cat door insert for sash windows:

  • Allows your cat to go outside when they want
  • Keeps out bugs and other critters
  • Easy installation process
  • Adds aesthetic touches to your home
  • Provides freedom and security to cats

If you’re looking to give your pet some freedom and security, a cat door window insert from Pet Door Products might be just the thing for you.

Do I Really Need a Cat Door Window Insert?

Many cat owners find it challenging when trying to decide if they want to invest in the best cat doors for windows. To help you make this decision, you’ll want to weigh the pros and cons. In addition, it really depends on what type of cat you own. With active cats who are always on the go, buying a cat door is the smart decision. Not only will your cat love you for it, but you’ll also never have to open the door for your cat again! Sounds great, right?

Our Cat Door Panel Window Inserts Can Also be Used as a Window Dog Door for Smaller Breeds

Pet Door Products makes life easier for pet owners by providing a cat door window insert that fits right into existing sash windows. This means that pet owners can begin enjoying the benefits of their dogs and cats being able to let themselves out at all times of the day and night.

If you’re searching for the best sliding glass pet door company in all of Utah, then Pet Door Products is the place for you. We specialize in easy-to-install, energy efficient pet doors for your beloved cats and dogs. Call today for more information about our small cat flap for glass!

Flap Sizes

Cat Door Window Insert Size Chart

Flap Size Flap Dimension Height To Raise Window
Small 6″ w x 11″ h 18 1/2″
Medium 8″ w x 15″ h 22 1/2″
Large 10″ w x 19″ h 26 1/2″
Extra Large 12″ w x 23″ h 30 1/2″

Window Cat Door Adjustment Ranges Include

22″ – 25″ 25″ – 28″ 28″ – 31″ 31″ – 34″ 34″ – 37″ 37″ – 40″ 40″ – 43″


Important Note

All Extra Large and 22″-25″ adjustment range sales are final, no returns. Please simulate the opening (open the window, use duct tape to simulate the opening) to be sure this size is appropriate before ordering.

Our normal 90-day return policy and 15-year warranty applies to Small, Medium, and Large sizes as well as all other adjustment ranges

There has been lots of discussion as to why the Endura Flap is such a high performing pet door, but for engineers or those looking for some more technical information here is a 74-page dog door energy efficiency study showing what makes it so special.

Endura Flap Pet Door Warranty

To the original purchaser, Endura Flap Pet Doors warrants this product and all of its component parts to be free of defects in materials or workmanship for a period of 15 years from the date of delivery to the customer.

Endura Flap assemblies employed in commercial kennels are warranted for a period of 3 years.

Damage caused by accident, improper installation, abuse or normal wear, including damage by pets or glass breakage is specifically excluded from this warranty. Defective materials returned to Endura Flap Pet Doors together with proof of purchase, will be repaired or replaced and returned to the customer free of charge.


Popular Cat Door Window Insert Features Include:

  • Highly insulating flap with a complete magnetic seal, designed to stay closed in winds up to 50mph. The flap is made out of a polyolefin-based polymer which can keep your home comfortable in temperatures between -40 and 110 degrees Fahrenheit
  • Dual-pane, LoE glass gives you extra insulation for your home and pairs perfectly with newer energy-efficient windows
  • Fits all vertical sliding sash window widths between 22”-43” with a track width of at least 1“
  • 4 sizes available to fit cats to large breed dogs (NOTE: Endura Flap medium, large and extra-large sizes are not recommended for use by kittens or tiny dogs)
  • 3 color options including white, satin, and bronze (very dark brown)
  • Includes a draft sstopper and weatherstripping for extra insulation and weather resistance
  • Can be installed and removed in minutes due to the spring loaded design. No tools are required!
  • 90-day return policy for Small, Medium, and Large sizes as well as all adjustment ranges besides 22”-25”
  • 15-year warranty for all pet doors
  • 100% made in the USA

Replacement Parts and Accessories for Cat Door Window Inserts

  • Replacement Flap
  • Locking Cover
  • Height Extension
  • Weather Stripping
  • Draftstopper
  • Installation Kit


Where to Buy Cat Doors Window Insert?

We’d love for you to buy your cat door window insert from us! And we work hard for your business, by offering you:

  • Our 90-day return period, covering cat door window inserts in all size adjustment ranges other than 22” – 25”
  • A 15-year warranty on all our pet doors
  • Materials made 100% in the U.S.
  • Window inserts built to keep the cold or heat from entering your home. As compared with the thinner inserts on the market, you’ll experience the benefits of a strong glass-and-vinyl frame, with a weatherproof seal. You’ll reap a return on your investment over the seasons through energy savings
  • A relationship with a business that cares about the community. We give 5% of our proceeds to support the lifesaving work of the Humane Society of Utah. We continually spotlight a pet who needs a home. We pay the adoption fees, too!

Which Size Cat Door Do I Need?

A cat will need to use a small or medium door. Measure your cat’s width and height. As shown on our measuring guide, the top of the door flap should be at least as high as the top of your cat’s shoulder. One of these two sizes will fit:

  • Small Cats6″ in width by 11″ in height.
  • Medium Cats: 8″ in width by 15″ in height.

Don’t hesitate to call us if you have any questions. Selecting the right size door will support your pet’s long-term comfort and well-being.

Do I Have Color Choices?

We offer three desirable color options for our cat door window inserts:

  • White: a perfect match for many home windows.
  • Satin: a smooth silver, similar to the matte side of aluminum foil.
  • Bronze: a dark, rich brown hue.

The inserts have a discreet frame design, allowing the maximum area for viewing. A security panel slides smartly over the opening whenever you prefer not to allow pets to go in or out.

Is a Cat Door Window Insert Secure and Will It Keep My Cats Safe?

The short answer to this question is yes, cat door window inserts can be secure, and they can keep your cats safe. Cat door window inserts are designed to provide your cats with access to the outdoors while still maintaining the security of your home. These inserts are typically made from a durable plastic or metal material and are designed to fit securely into the frame of your window. They come with a locking mechanism that prevents unauthorized entry and keeps pets from escaping. Additionally, many cat door window inserts also feature an alarm system that will sound if someone tries to break in. With the right cat door window insert, you can easily protect your cats and keep them safe.

Need help with your decision? Learn more!

Are There Any Special Considerations When Choosing a Cat Door Window Insert?

Yes, there are several factors to consider when choosing a cat door window insert. Firstly, you need to make sure the insert is the right size for your window and your cat. You also need to consider the weatherproofing of the insert, as well as its security. Make sure the insert is made of durable materials and has an adequate locking system so that your cat can stay safe and secure. You’ll also want to take into account any other features you may need, such as a dual-flap system or a timer for when you want to keep your cat inside for a period of time. Finally, ensure that the insert is simple to install and maintain. With these considerations in mind, you’ll find the perfect cat door window insert for your needs.

What Are the Drawbacks to Using Cat Door Window Inserts?

There are a few drawbacks to using cat door window inserts. Firstly, the cat door window insert will reduce the amount of natural light that enters your house, as it will take up part of the window. Secondly, the insert may not be energy efficient, as the seal may not be as good as a regular window pane. Finally, the cat door window insert may be more costly than just purchasing a regular window with a cat door already installed.

Do You Ship?

Yes. We ship from Pet Door Products in Utah, straight to your home. Once you place your order, depending on the distance, your new cat door insert may arrive in just three days—and always within a week. Get a jump on the cold weather! Within days, you and your pet will have the freedom and comfort you’ve been wishing for.

Call or text us at (801) 973-8000 to arrange your immediate shipment.

17 reviews for Cat Door Window Insert

  1. 5
    (17 customer reviews)
    100% of customers recommend this product.
    5 Stars100%4 Stars0%3 Stars0%2 Stars0%1 Star0%
  2. Carly

    The product arrived and I installed it the same day. Our dogs started using it by the next afternoon. Thank you!

  3. Kamla

    They did such an amazing job with the outdoor! It doesn’t let any cold air in, and the dogs love it!
    Thank you Pet Door Product

  4. julianena

    Great service and help full staff. Now my cat can easy to go out. Thank you Pet Door Product

  5. Julie

    I was so impressed! Their cost was competitive. The 10-year warranty eases my mind on that part as well. Now my Dog can sun bathe on our porch to his little heart’s content.

  6. Ronny

    This allows our cat to come and go, plus we get to take the door with us when we move.I spent and my cat loves the freedom of coming and going when she wants.

  7. Toni

    Great service and help full staff. My cat also loves it now my can go out easily. They did such an amazing job outdoor! I spent and my cat loves the freedom of coming and going when she wants.

  8. Dave

    I spent and my cat loves the freedom of coming and going when she wants. Thank you Pet Door Product.

  9. Gracey

    We are so happy because my cat can easy to go out. Thank you

  10. Katie

    I love this door, so do my dogs! They love having the freedom to go outside and come inside when they want. Thank you Pet Door Products

  11. Buddy

    They did such an amazing job with outdoor! I spent and my cat loves the freedom of coming and going when she wants. Thank you Pet Door Product

  12. Helena

    My experience with them was exceptional from beginning to end.The install time for the new glass and dog door was 30 min or less and the installer was very fast and professional as well.The product itself is wonderful! My cats also adjusted to the new door very quickly which was great! We all just love it!

  13. Bud

    Great service installing my door. The door seems to be excellent quality and the pet door is very well insulated. Cat loves the door and is in and out all day.

  14. Jini

    Great service and help full staff. My cat also love it now my can go out easily.
    Thank you!

  15. Rojar

    We love our Pet Door! The door itself is really great quality. Our Cats love the freedom to go in and out when they want and I love not having to go open the door every 5 minutes. I highly recommend working with Pet Door Products.

  16. Jelly

    The product and service it’s very excellent. Cat love to go out anytime. Thank you

  17. Richard

    Pet Door was awesome to work with! We purchased the insert from out of state and they coordinated working with a local company to get it installed.

  18. Jason

    This is an awesome pet door! We are renters and cannot make changes to the home. This allows our cat to come and go, plus we get to take the door with us when we move.

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Customer Reviews

What Our Pet Door Customers Are Saying

Kaylie Shaw
May 31, 2024

Patrick was awesome! He was super helpful and detailed with the whole process.

Levi Peterson
May 31, 2024

Great product and great experience through the whole process! Patrick really helped us find the right fit for our dog.

Scott Eliot
May 31, 2024

We had a great experience working with Patrick. He gave us a fair quote and the install was quick. Our dog Charlie loves being able to come in and out as he needs. When I get a bigger house with more doors I’ll be sure to reach back out to Pat and the Pet Door team.

Mandi Jones
May 26, 2024

We love our pet door. It’s a clean and professional look. Highly recommend.

Angela Sachs
May 24, 2024

Pet Door Products have been wonderful to work with. They are quick and reliable! I was a bit worried about my VERY LARGE lab fitting through the door but it’s perfect and both of my dogs picked up on it so quickly. I also love that the magnet that keeps the flap closed is strong enough to stay closed during wind storms. Can’t say enough about this product and how much my dogs and my family are enjoying this.

Stacy Basham
April 29, 2024

Excellent service, great install and very high quality product. Very impressed with the durability and structure of the product. Would recommend to family and friends.

Adam Lay
April 29, 2024

Great experience overall with Pet Door Products. They came out quickly to get me a quote, and once the glass was in stock they came out promptly to install it. The end result is beautiful, my dog loves the ability to go out on his own and I love that I can lock my sliding door again!

Holly Smith
April 29, 2024

We’ve been needing a dog door for awhile. Pet Door products made getting a door super easy. Everyone was so nice. The install was fast and the door arrived before expected. We tried another company before Pet Door Products and we did not have a good experience. Nobody followed up and they didn’t come back when they were suppose to. But Pet door products was the exact opposite. Fast, friendly, professional and a great product. My dog is enjoying the door and I am glad I don’t have to get up anymore to let her out. Win win for all! Holly Smith

Reilly Kelly-bloxham
April 29, 2024

Pat was great to work with and explained how everything would get installed. Pricing was extremely fair and the install only took about 35 min. 10/10 recommend if you’re on the fence about getting one.

Charisse Olsen
April 26, 2024

So far I've been very happy with my experience. I called Pet Door Products and in less than 24 hours had an appointment and meeting with their Representative Patrick. The process has been quick and easy and very informative I would highly recommend the company.

Nick Birdzell
April 25, 2024

Great service from Patrick. Quick responses great customer service

Kaelin Griffiths
March 28, 2024

Quick and simple, I recommend! My dogs figured it out quick. It’s been so nice to have, especially during bad weather when I’m not home, knowing the dogs can come in and out as they need.

Kody Mayo
March 28, 2024

We love it. Much better than cutting a hole in the side of my home. It looks great, fits perfectly and is great quality.

Dylan Harding
March 28, 2024

Got a door installed a few months ago and it was a breeze! Patrick is such a great guy and met all my dog door needs!

Tom Caswell
March 28, 2024

Patrick and his team were always on time and professional. They did an excellent job with top quality materials for about half the price of the other quote I got. Highly recommended!