Custom Endura Flap Thermo Panel 3e

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  • Removable panel with built-in dog door fits into sliding glass door track
  • Durable, aluminum frame and pet door made to withstand extreme climates
  • Dual-pane, Low-E glass improves energy efficiency
  • Tool-free installation 
  • Adjustable heights and custom sizing to fit all sliding glass doors
  • An email will be sent to you requesting additional information for your custom order

The Endura Flap Thermo Panel 3e is a highly insulated dog door for sliding glass doors that fits into your existing track. This removable panel does not require tools for installation, as the spring-loaded design safely secures it in place without permanent alterations. Engineered with dual-pane, Low-E glass, and a polyolefin polymer flap that magnetically seals, the Thermo Panel 3e provides supreme insulation and energy efficiency. Withstanding extreme temperatures as low as -40 degrees Fahrenheit, the thermal quality of the Endura Flap Patio Panel is engineered to prevent heating and cooling loss common among other patio panels. The built-in doggie door will grant your pets the freedom they crave while simultaneously saving on energy bills. 


  • Pet flaps range from Small to Extra Large
  • Patio Panel comes in three height ranges to accommodate common sliding glass door sizes
  • Custom height ranges available by special order
  • Heavy-duty aluminum frame designed for sliding glass door tracks at least 1” thick
  • Dual-pane, Low-E glass minimizes the amount of infrared & ultraviolet light coming through the glass without minimizing the amount of light entering the room
  • Environmentally-friendly polyolefin polymer flap remains flexible and usable in temperatures as low as -40 degrees Fahrenheit
  • Magnetic closure on three sides of the flap enhance storm and wind resistance.
  • Durable and secure locking cover included
  • C-Clamp Lock included for to lock the slider into the door frame or a Charley Bar can be purchased separately
  • Designed and engineered in the USA



  • Easy installation with spring-loaded design allows you to remove the panel easily if need be
  • Included locking cover allows you to block access when needed
  • Structurally sound design is built to last so you don't have to spend a fortune on replacement flaps

Size Chart

Flap SizeFlap DimensionStep Over RangeOverall Panel WidthRecommended Pet Height*
Small 6" w x 11" h3" - 5"11 3/8"9“ -  15"
Medium 8" w x 15" h3" - 5"13 3/8"9" - 19"
Large 10" w x 19" h3" - 5"15 3/8"9“ -  23"
Extra Large 12" w x 23" h3" - 7" (ships at 5")17 3/8"9“ - 29"


Here is a measurement guide to help you out. Wondering how to measure your track? Review our Track Measuring Guide.

Track Height Adjustment range is based on the measurement of your door height from the lowest point of your track to the highest point. Each Custom Endura Flap Thermo Panel 3e has a 3" adjustment range with your window track height approximately in the middle. The following adjustment ranges are available pre-built:

  • Short: 74 3⁄4" – 77 3⁄4"
  • Regular: 77 1⁄4" – 80 1⁄4"
  • Tall: 93 1⁄4" – 96 1⁄4" (additional cost)


Custom Height Minimum & Maximum Heights:

Extra Large46"123"


If your measured track height does not fall within one of the ranges above, we can make a custom height. Choose the range that your track height falls into and when ordered you will be asked to give the exact height of your slider track inside very top to very bottom. In each case you will have 3" of height adjustment with the height you specify approximately in the middle of that range. The ranges are: 

  • Under 74 3⁄4"
  • Between 80 1⁄4" – 93 1⁄4"
  • Over 96 1⁄4"


Most sliding glass doors will accommodate the three-panel sizes offered. However, if our standard panels do not match your door size, we can build a custom Thermo Panel 3e for you. We can also custom make a panel for left-to-right sliding sash windows as long as the window track width is at least one inch. Custom height option may take up to 4 weeks to special order the glass and build the panel.

The panels have a 3-inch spring-loaded height adjustment, so if you request a 40" panel, the panel you receive will adjust from 38" to 41" inches. If your measured track height is near the bottom of the adjustment range then you should review A Note of Caution 

Additional Information

YOUR MAXIMUM PET SIZECats, Large Cats, Small Dogs, Medium Dogs, Large Dogs, X-Large Dogs
SEALING VALUEVery High, High, Average, Low
TYPE OF WINDOWSideways Sliding
FRAME MATERIALHeavy Extruded Aluminum
FLAP MATERIALEngage Polyolefin
FLAP DESIGNSingle, One Part , Flexible, Insulated Flap
CAN BE INSTALLED INDual Pane Glass Sliding Glass Door, Single Pane Glass Sliding Glass Door, Vinyl-Framed Sliding Glass Door
RETURN PERIOD90 days (except for custom height ranges)

Installation Instructions

Thermo Panel 3e Installation



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 Sliding Door Clamp




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.


ADJUSTING THE STEP OVER HEIGHT - OPTIONAL (for aluminum panels only)

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:

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.



ENDURA FLAP® PET DOORS: Endura Dog Door Impact Test

How to Measure Your Sliding Glass Door for a Pet Door

How to Adjust the Magnet Strength on Your Endura Flap


What is the thickness of the panel?

The patio pacific endura flap thermo panel 3e is 1" thick. It is only thick enough for a single flap, not a double flap.

Does this panel work with vinyl sliders?

Yes, the endura flap 3e is compatible with most vinyl sliding patio doors for a vinyl-pet slider that matches your existing track. At 1" thick, it is thicker than most aluminum panels, so it will fit better in a vinyl track. The track width may not line up exactly with the panel, but it is only an issue with the aesthetics, not functionality.

Does this keep mice, rats, and other pests out?

This is a manual door, so there is no guarantee that critters will not get in. However, the Endura Flap has incredibly strong magnets that are hard for small critters to push through and get in.

How do I measure my door to get the correct height adjustment size?

Measure from the innermost part of the bottom track to the innermost top part of the track. If there is a pencil railing, include that in the measurement because the panel straddles the railing.

What do the Step Over Range dimensions mean?

The step over is the part of the panel under the actual door opening. Depending on the flap size purchased, the stepover can range from 3"-7". This means that you can adjust it to any stepover within that range. So if you have a puppy, you can keep adjusting it as he/she grows.

Will there be enough room for me to get through after the panel is installed?

That depends on how wide your sliding glass door opens and how wide the panel you purchase is. Those dimensions can be found under the "Overall Panel Width" column.

Can an intruder remove the Endura Flap dog door for slider from the outside?

No, the thumbscrews are on the inside of the panel, so once installed, the Endura Flap Panel cannot be lifted out and removed without first loosening the thumbscrews from inside the home.

What locking mechanism can I use for the Thermo Panel 3e?

You'll install the included clamp lock. Alternatively, the Endura dog door/cat door for sliding glass door can be secured with a Charley Bar for added security.

Does the Endura Flap dog door sliding door come with locking covers for security?

Yes, these dog doors come with locking covers to ensure safety for your pet and home. Endura Flaps have locking covers that slide over them on the side facing inside your home and are made of sturdy, heavy-duty ABS plastic. Unfortunately, they cannot be used on the outside of Endura Flap Panels as an alternative.

Do the Endura Flap panels require tools for installation?

Endura Flap sliding glass dog doors under 80 ¼" do not require tools, making them one of the best dog doors for rental homes! However, everything above this height generally will require some tools for installation. What we call a sectional panel will be shipped in two pieces because it is so tall. Breaking the pet door for sliding door down saves the customers on shipping costs, because we are able to ship in a smaller package. The sectionals will need to be assembled with 4 hex screws and a hex wrench, all of which are provided.

Is this door good in a cold winter climate? I want something effective in our winter months. 

Yes, the Endura Flap has been tested in -4°F.


Endura Flap products have a lifetime warranty against defects in materials and workmanship under standard regular use. Damage caused by not using the product as intended, improper installation, and chewing is not covered under this warranty.

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