Custom Endura Flap Thermo Panel 3e for Windows

SKU# 01PPCust

  • Adjustable heights and custom sizes to fit any sliding window
  • Durable frame and pet door made to withstand extreme climates
  • Made with dual-pane, Low-E glass to improve energy efficiency and reduce infrared & ultraviolet light
  • Does not require any tools for installation
  • Custom-made panels are final sale and non-returnable

View Warranty

Stock No: 01PPCust

Availability: In stock

Price From: $580
Loading options please wait..
What size do I need?
Price From: $580
Custom Endura Flap Thermo Panel 3e for Windows
The Endura Flap Panel is the foremost product on the market that combines style, comfort and reliability. It is specially designed with over a decade of research for the ultimate doggie door experience.

Hover over image to zoom

  • Adjustable heights and custom sizes to fit any sliding window
  • Durable frame and pet door made to withstand extreme climates
  • Made with dual-pane, Low-E glass to improve energy efficiency and reduce infrared & ultraviolet light
  • Does not require any tools for installation
  • Custom-made panels are final sale and non-returnable

In each case you will have 3" of height adjustment with the height you specify approximately in the middle of that range. 

Please note: If you order a custom insulated glass unit, it must be specially ordered which takes about 4 weeks. Since these are custom heights it's a final sale; no returns.

CAUTION: If your measured track height is near the bottom of the adjustment range then you should review A Note of Caution

Please Note: Don't think that the 12" width isn't enough unless you actually measure.  12" is Huge!  

Wondering how to measure your track? Review our Track Measuring Guide.

Flap SizeFlap DimensionStep
Stock No
Small #66" w x 11" h3" – 5"11 1⁄4"01PPC06
Medium #88" w x 15" h3" – 5"13 1⁄4"01PPC08
Large #1010" w x 19" h3" – 5"15 1⁄4"01PPC10
Extra Large #1212" w x 23" h3" – 7" (ships at 5")17 1⁄4"01PPC12

Don't know which flap size to get? Here is a measurement guide to help you out

Minimum and Maximum heights vary by flap size. Here's the info

Custom Height: Minimum & Maximum Heights
Small #635"100"
Medium #842"107"
Large #1048"117"
Extra Large #1246"123"

This is the custom design page for the Endura Flap Thermo Panel 3e for side-to-side sliding windows of unusual heights. The track height adjustment ranges for custom orders are for windows under 74 ¾”, between 80 ¼” ‒ 93 ¼”, and over 96 ¼”. Please note that custom-made doors are non-refundable and non-returnable. The panels have a 3-inch spring-loaded height adjustment, so if you request a 40-inch panel, for example, the panel you receive will adjust from 38 to 41 inches.


About the Door:

The Endura Flap Thermo Panel 3e is a spring-loaded design that fits into your sliding windowtrack at least one inch thick without the use of any tools. It features dual-pane, Low-E glass to prevent UV rays and infrared light from entering and to efficiently insulate your home. With a flexible, pet and environmentally flap lined on all three sides with magnets, heavy wind will be unable to blow through. Save on heating and cooling with this insulating flap!



  • Pet flaps come in small, medium, large & extra large
  • Flap dimensions designed to accommodate pets of multiple sizes
  • Aluminum frame designed to fit into the window track with width of at least 1” thick
  • Dual-pane, Low-E glass allows natural light to enter while blocking out unwanted UV rays and infrared light
  • Flap withstands -40 degree temperatures and stays sealed in 50mph winds
  • Magnetic sealing resists heavy winds/storms
  • Flap swings on a rod at the top, avoiding breakage
  • Includes a sturdy locking cover
  • C-Clamp Lock included for adjustment ranges under 74 ¾” to lock the slider
  • Foot Lock included for adjustment ranges 80 ¼” and above to lock the slider



  • Removable panel benefits all owners, especially renters!
  • Don’t have to make any permanent alterations to window
  • Available in white, bronze, or brushed aluminum to match your window
  • Pets can enter and exit as they please
  • Locking cover prevents pets from leaving the house when you want to keep them inside
  • Long lasting
  • Built in the USA
  • Free shipping in the U.S.

Customer Reviews

Set Direction
  • Awesome-ness review by Louie
    5 5 Awesome-ness

    This door is a thing of beauty and class. I love it! It fits nicely in my window. Theres no extra noise. There is no outside elements coming in. I would buy this again in a heartbeat. Two thumbs up endura flap!!

    (Posted on 9/10/2018)

  • amazing review by scott
    5 5 amazing

    This door was so well worth the money spent. It is so insulating and efficient. I have my air conditioning on and it does not escape through the door. The outside air does not come in either. It was built to fit my window perfectly. I am so impressed with this quality of the door. My dogs are so happy!!1

    (Posted on 9/6/2018)

  • Perfect product.. review by mitchie
    5 5 Perfect product..

    My windows open side to side and no one makes a window for cats that goes side to side except for Endura. It is everything I wanted. It is dual pane, stylish, sturdy, energy efficient ect. The flap is staying shut with the weather and the wind. I could not ask for anything better.

    (Posted on 6/15/2018)

  • Works great review by Cheryl
    5 4 Works great

    So, you see...apparently my sliding door isnt a "normal" size. I thought all sliding doors were more or less standard and mine fell outside that range. Customer Service worked with me and were very helpful in getting my door sized correctly. I received it a few weeks later and it works perfectly. I just wish that they made panels in standard sizes...

    (Posted on 2/21/2018)

  • Works great for horizontally sliding widows review by Mia
    5 5 Works great for horizontally sliding widows

    I wanted a cat door for a window that opens side to side. After a lot of thought and conversations with customer service, I have finally decided on this one. It was a bit scary to order because it is custom and non-refundable but the customer service staff was able to answer all my questions and helped me place the order. I just received it and it fits great in my window!

    (Posted on 12/27/2017)

Weight 1.0000
Manufacturer Endura Flap
Your Maximum Pet Size Cats, Large Cats, Small Dogs, Medium Dogs, Large Dogs, X-Large Dogs
Climate Suitability Severe-4 Season
Sealing Value Very High
Wind Resistance Very High
Type of Window Sideways Sliding
House Locking Method C-Clamp Lock
Frame Material Heavy Extruded Aluminum
Custom Heights Available Yes
Can Fit Sideways Sliding Windows Yes
Track Width Minimum 1"
Built-In Adjustment For Small Measuring Errors Yes
Tools Required For Installation none
Patented User-Adjustable Step Over Height Yes
Employs Patented “Endura Flap” Yes
Insulation Value High
Possible to Add Additional Magnets for Greater Wind Resistance Yes
Flap Material Engage Polyolefin
Flap Design Single, One Part , Flexible, Insulated Flap
Flap Colors Clear
High Aspect Ratio Yes
Flap Thickness 7/8"
Award Winning Design Yes
Flap Warranty (if separate) 15 years
Locking Cover Material Dimensional ABS
Can Be Installed In Dual Pane Glass Sliding Glass Door, Sideways Sliding Windows, Single Pane Glass Sliding Glass Door, Vinyl-Framed Sliding Glass Door
Dual or Single Pane Dual Pane
Low “E” Coating Yes
“Draft Stopper” Included to Seal Stationary & Sliding Panel Overlap Yes
Warranty Period 15 years
Return Period Not Returnable
Manufacturer's Restocking Fee 0

The Endura Flap Pet Door



The Thermo Panel 3e Patio Panel Pet Door



Removing Side Magnets



Variable Magnetic Resistance



Adjusting the Step Over Height



The Leaf Blower Test



Get a Discount on a Bug Warden (an essential accessory if you ever leave your sliding door open for ventilation)

Although this video illustrates how to install the panel in a sliding glass door, the installation will be the same for your window.


Installation Instructions for the Custom Endura Flap Thermo Panel 3e for Windows



All Panels

  • 1x Foam Weather Strip
  • 1x Center Post Weather Seal Draft Stopper

1 Piece Pet Door

  • 1x Panel Pet Door
  • 1x Sliding Door Clamp

2 Piece Pet Door

  • 1x Top Glass Panel Section
  • 1x Bottom Flap Section
  • 4x Hex screws
  • 1x Hex wrench
  • 1x Threshold mount deadbolt with screws



The aluminum, vertical panel has a patented ‘Adjustable Step-Over’ feature which permits adjusting the height of the flap to the most comfortable fit for your pet. Generally, the top of the flap should be positioned to be at least 1” (2,5 cm) above the top of the pet’s shoulder (the ‘withers’). If the factory setting is not suitable, please adjust it before proceeding. If the current setting is suitable, or you have the vinyl panel, proceed to step 3.



Step 1A: Two-piece panels: Simply slide the pieces up and out from the bottom half of your panel to rearrange. Loosen a bottom screw if the pieces are too snug to move.

One-piece panels: Lay the entire panel on a flat surface (like the floor). Using a #2 Phillips head screwdriver, remove the bottom side-screws, and loosen the next upper screws one turn. Screws were tightly installed to hold the panel together during shipping; a drill is recommended*.

*If you do not have a Phillips head drill bit skinny enough to fit, let us know and we’ll send you one for free.

Step 2B: One-piece panels: Once the bottom screws have been removed and the next upper side-screws loosened, the Pet Door Assembly and spacers can be removed by sliding the sections down and out of the panel. 

Step 2C: Replace the spacers and the Pet Door Assembly by sliding them back in a different order to achieve the desired height. You can move the spacer below or above the flap to raise or lower the flap height.

The order of the pieces is important! The piece on the bottom needs to always be at the bottom, as that is where the screws attach. 

When finished, replace the bottom side-screws and tighten the next upper-side screws for one piece panels and skip to step 4. For two-piece panels, you can now assemble the patio panel!

Please Note: A lower step-over height is easier for pets to navigate. However, if the top of the flap is low enough that the pet needs to crouch to get through their pet door, they can injure themselves and possibly cause the pet door to malfunction. If your pet door does not sit at a comfortable height for your pet, you may need a larger size flap. 


(if you have a single piece panel, please proceed to step 4)

Step 3A: Align the aluminum connectors extending from the bottom flap panel section with the top glass panel section. Press the aluminum connectors into the holes at the bottom of the top glass panel section. Ensure locking cover & thumb screws are on the same side!

Step 3B: Gently tap the bottom surface of the panel against the ground to completely insert the connectors. Protect hard surfaces to prevent scratching. The components of the panel are designed to slide together very tightly.

Step 3C: Fasten the two panels together using the four stainless steel hex head screws found in the panel packaging. Use the hex wrench to tighten screws so the two halves of the door are pulled together.
Please Note: Screw holes may look misaligned; this is intentional to ensure a tight fit. The panels will squeeze together as the screws are tightened.

Step 4: Loosen the thumb screws at the top of the pet panel. This allows the spring mechanism to move freely up and down.

Step 5: To insert the panel pet door into the top track, push up against the spring mechanism and swing the bottom of the panel up and over the threshold. Seat the panel on top of the small guide rail in the track. If you can’t quite get it in the track, try swinging in from the outside as the outside track wall may be shorter.

You want to put the pet door in your track before applying any weather-stripping to ensure it fits! If it fits well, move on to the next step. See our tips at the end of these steps if you have trouble!

Step 6: Once you’re sure the panel fits, remove the panel from the frame and lay it on its side on the ground. Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the panel, pressing to ensure it adheres. Install on both sides, trim to fit with scissors. 

Step 7: The center post weather seal strip (draft stopper) should be installed on the inside of the home. It can install on either the back edge of the sliding door panel or the leading edge of the stationary panel. This strip prevents air leaking between the sliding glass door and the stationary panel. Trim with scissors as needed. Clean the edge of your patio door with rubbing alcohol before installing to assure a good seal.



Since you cannot lock your sliding glass door to your panel pet door, we have provided you with an alternative locking method to secure your home:

DOORS OVER 80 1⁄4” (203,8 cm) Tall

Installing the threshold mount deadbolt lock: For doors manufactured with the glass slider on the inside track, the lock can usually be installed on the back of the slider using the mounting screws provided. For doors manufactured with the slider on the outside, the lock is installed on the leading edge of the stationary panel.

Drill a 3⁄16” (4,8 mm) hole into the frame opposite the steel deadbolt lock. This hole MUST be 3⁄4” (1,9 cm) away

from the inside edge of the door’s frame to avoid drilling into the glass. Drilling into the glass will cause the glass to shatter.

DOORS UNDER 80 1⁄4” (203,8 cm) tall

Installing the sliding door clamp: This clamp has a screw which tightens by hand to prevent the sliding door from moving beyond the clamp’s placement. For doors manufactured with the glass slider on the inside track, the lock can usually be installed on the door’s raised track.


For help with installation, replacement parts or other questions visit or call 805-781-7700 Monday – Friday, 7am – 4:30pm PT



Click below to expand:

You would need to measure from the deepest part in the bottom track to the deepest part up inside the top track. Also the panel is 1" in thickness so make sure that your track is at least that wide to be able to accept the panel.

That is how far from the bottom of the pet door the flap actually starts. So it is what your pet would have to comfortably clear in order to get out and in.

These are excellent for insulation as they have dual pane low-e glass, and the Endura flap pet door which happens to be one of the best sealing and energy efficient doors on the market.

It is meant for more of the DIY (do it yourself) type of installation. In the really taller heights it can be a bit tricky since the panel is tall and heavier, so it is helpful to have an extra set of hands. I would suggest taking a look at videos tab for a better ideal of just what the installation looks like.

Yep! We include a closing cover that you slide in place. The tracks are located inside so you don't have to go outside in bad weather to close it off.

We include a clamp lock for panels under 80.25" and a foot lock for all panels over 80.25". You can also use a charley bar, or the old dowel in the track method. All of these different mechanisms work off the same principle that when in place the prevent the sliding door from being pulled away from the pet door panel.

No, the panel is held in at the top with a spring loaded adjustment piece. Once the thumb screws, located on the inside, are tightened you can't slide down that piece in order to remove it.

The framing is a heavy gauge aluminum.

We do have the Thermo Panel 2e panels, but the largest flap is on 7" x 7" in Pet Door version. So it is recommend more for cats and pretty small dogs.

Being that they are custom and we have to special order the glass it can take roughly 4 weeks for delivery.

Yes, you can order a Thermo Panel to accommodate your shorter door. When choosing the Track Height Adjustment Range, select "cust ht under 74 3/4 and then you will be prompted to enter your track height. We will build a panel to your specifications.

Write Your Own Review

You're reviewing: Custom Endura Flap Thermo Panel 3e for Windows

  • 1 star
    2 stars
    3 stars
    4 stars
    5 stars

* Required Fields

Patio Pacific Inc Endura Flap™ Pet Door Warranty

To the original purchaser, Patio Pacific Inc 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 are warranted for a period of 15 years. 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 Patio Pacific Inc, together with proof of purchase, will be repaired or replaced and returned to the customer free of charge.

Pet doors of other manufacturers installed in Patio Pacific products are covered by the warranty of the other manufacturer and not by Patio Pacific Inc.