Cat Door Panel Window Insert

(17 customer reviews)


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

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

Cat Door Window Insert

SKU: #001-1-1-2 Category:

Additional information

Height 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.


It’s your cat always itching to go outside? If so, then you can reap great benefits by installing our amazing cat door window insert!

Cat Door for Window Benefits

Installing a new cat door for windows Pet Door Products can make your cat the happiest feline in the world. Take a look at these key advantages of installing a Cat Door Insert for Sash Windows:

Choosing one of our incredible car doors can take your home to the next level

Do I Really Need a Cat Door?

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 pretty great, huh?

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

Pet door flap sizes graphic - Cat doors for windows

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 return. 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 Flap Window Insert Features Include…

  • Highly insulating flap with a complete magnetic seal, designed to stay closed in winds up to 50mph. 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, 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 seconds due to the spring loaded design, no tools 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

  • Replacement Flap
  • Locking Cover
  • Height Extension
  • Weatherstripping
  • 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 USA
  • 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 Cats: 6″ 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:

  • 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.

How Is the Cat Door Secured in My Window?

Energy-efficient window inserts from Pet Door Products fit right into your sliding glass door. No tools are needed to secure the removable insert with its advanced, spring-loaded design. By installing your window insert yourself, you’ll spend less with our DIY discount, and install it on your time—no coordination with Pet Door Pro required.

For the permanent option, we can replace your window with a new one. We’ll set up an appointment with you for the window replacement. Your new window will have a cat door built right into the glass.

Need help with your decision? Learn more!

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 Panel Window Insert

  1. 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.

  2. 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.

  3. Jelly

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

  4. 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.

  5. Jini

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

  6. 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.

  7. 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!

  8. 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

  9. 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

  10. Gracey

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

  11. Dave

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

  12. 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.

  13. 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.

  14. 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.

  15. julianena

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

  16. 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

  17. Carly

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

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