FAST U.S. SHIPPING & EASY RETURNS

Endura Flap Thermo Sash 3e Cat Doors for Sash Windows

Endura Flap Thermo Sash 3e Cat Doors for Sash Windows

Regular price
$409.99
Sale price
$409.99
Regular price
Sold out
Unit price
per 
Shipping calculated at checkout.
White
Bronze (Black)
Brushed Aluminum

This field is required.

  • Energy-efficient window cat door for sash windows 22" - 43" wide
  • Spring-loaded, easy installation, with no permanent alterations
  • Flexible, weather-tight flap remains secure in extreme conditions
  • Locking cover included for added security
  • Panels less than 22" will have no glass 

Custom Order | Ships in 1-3 Weeks | Non-Returnable

Product Details


The Endura Flap Thermo Sash 3e Cat Door is the perfect solution for cat owners looking to provide their feline companions with the freedom to roam without compromising the energy efficiency of their homes. This innovative cat door for sash windows is designed to fit a wide range of window sizes (22" - 43" wide, 1" thick track) and installs effortlessly with a spring-loaded design, ensuring a secure and weather-tight fit without any permanent alterations.

Constructed with an extruded aluminum frame, the Thermo Sash 3e Cat Door boasts a energy efficient design. This feature is ideal for those who want to maintain their home's insulation in extreme weather conditions, and is further enhanced by a flexible, environmentally friendly polyolefin-polymer flap that remains securely sealed even in 50 mph winds and -40°F temperatures.

The cat door's 6" x 11" flap size accommodate cats of all breeds and sizes, while the adjustable magnets lining three sides of the flap create a tight, weatherproof seal. For added security, a durable ABS plastic locking cover is included, which loads from the top.

One of the key benefits of the Thermo Sash 3e Cat Door is its removable design, making it an ideal choice for vacation homes and rentals. Homeowners can avoid permanent alterations while still providing their cats with the freedom to come and go as they please. The door's flexible flap ensures a safe, pinch-free experience for your cat, and the thermal quality of the panel guarantees longevity and eliminates heating/cooling loss.

Join the many satisfied customers who have found the Thermo Sash 3e Cat Door to be a practical, energy-efficient, and aesthetically pleasing solution for their cat's needs. Experience the perfect blend of convenience, security, and insulation with the Endura Flap Thermo Sash 3e Cat Door for Sash Windows.

If you need a larger flap size you will find them on the Endura Flap Thermo Sash 3e Pet Doors for Sash Windows page.

Features:

  • Suitable for a wide range of sash windows (22" - 43" wide, 1" thick track)
  • Extruded aluminum frame for durability and aesthetics
  • Quick and effortless installation with spring-loaded design
  • Environmentally friendly, polyolefin-polymer flap stays sealed in 50 mph winds and -40°F temperatures

Size Chart

Flap Dimensions:

6"w x 11”h

The entry way your dog goes through.
flap dimensions
overall panel width

Height to Raise Window

18 1/2"

How high you must raise your window in order to fit the panel into the track.
Flap SizeFlap DimensionHeight To Raise WindowRecommended Pet Height
Small6" w x 11" h18 1/2"9" - 15"

Adjustment Ranges:

  • 22" - 25" Custom Order
  • 25" - 28"
  • 28" - 31"
  • 31" - 34"
  • 34" - 37"
  • 37" - 40"
  • 40" - 43"

 

Pet door has 1" framing, measure your track width to make sure that your window will accommodate the sash.

Final Sales: Adjustment Range 22" - 25" are final sale and cannot be returned. Final Sale products are made to order and will take extra time to ship.

 

Find The Best Pet Door Size For My Pet

A

Pet Height: inches

B

Pet Width: inches

Please fill the above fields.

Additional Information

Flap Material

Flexible

Your Maximum Pet Size

Cats

Installation Instructions

Installation icon Difficulty Easy
Installation icon Steps 04
Installation icon Time Required 0.5 hours
Installation icon Sections 01
Installation icon Flags 01

Parts

  • Sash Window Pet Door
  • Foam Weather Strip
  • Center Post Weather Seal Draft Stopper
  • Screwdriver

Tools

  • Flathead Screwdriver

Please read instructions & notes thoroughly before installation.

Step 1 Release Spring Mechanism

  • Loosen the width adjustment locks at the end of the pet door insert with the screwdriver. This allows the spring mechanism to move freely from side to side.

Step 2 Check Panel Fit

  • Insert the sash into the window track. Push against the spring mechanism and swing the opposite end into the opposite window track. Gently release. Tighten the width adjustment locks.

Step 3 Apply Weatherstripping

  • Remove panel from window track.
  • Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the sash, pressing to ensure it adheres. Install on both the top and the bottom. Trim to fit with scissors.

Step 4 Mount Seal Draft Stopper

  • Mount the Center Post Weather Seal Draft Stopper. This strip prevents air from leaking between the window frame when raised to accommodate the sash. Trim to fit with scissors.
  • Put the panel back into the window track. Tighten width adjustment locks.

Switch the Side of the Flap

You can switch which side of the sash panel the pet door flap is on to best fit your home.

Step 1

  • Remove the screws on the top and bottom closest to the edge of the pet door. Then slightly loosen the screws closest to the glass. Next, slide off the side piece, then the flap assembly.

Step 2

  • Rotate the flap assembly (essentially flipping it upside down) then slide it back in. Make sure the locking cover is on the same side as the width adjustment locks.

Step 3

  • Replace the end spacer and screws.

LOCKING YOUR WINDOW

For a permanent lock, install a wood screw in the track immediately above the window on both sides. You will no longer be able to raise the window. For a temporary lock, place a removable wooden dowel or Charley bar in either track above the window, shown in Detail 1.

HEIGHT OF YOUR WINDOW

Make sure you place steps or ramps leading to your pet’s door at a height that works! When they go through the flap, the top of the flap should be at least 1" (2,5 cm) higher than the top of their back. Watch your pet and adjust as needed to keep them comfortable.

Videos

How to Measure Your Sash Window for a Pet Door





Design of the Endura Flap





Adjusting Magnet Strength for Training





Leaf Blower Test


FAQ

What do I need to know/measure before I order?

First raise up your window and check that it can go up far enough to be left with an opening 18 1/2" high. Next measure the width of the track from left to right, including going inside the track on both sides. Last measure how wide the track is that the window slides in (needs to be at least 1")

How wide does the track have to be for the Thermo Sash 3e to fit?

Track width needs to be at least 1" thick.

Can I choose what side the door is on?

It comes standard on the left, if you are looking from the inside of the house. You can switch it to the other side if you need and that only requires a screwdriver.

Will this door be good for more extreme weather?

The Thermo Sash 3e has the Endura Flap which is far better in sealing and durability than other models. Dual pane lo-e glass offers superior insulation value. Therefore, the Thermo Sash will be a much more reliable and longer lasting option then the more inexpensive options.

Is it possible to make one that fits a window smaller than 22"?

We can, the only thing is that we would not be able to use glass so there would be quite a bit of aluminum and some customers are not happy with the aesthetics. This would also fall under the custom and non-returnable category.

My cat is having a hard time opening the flap is there something I can do that would make it easier?

You can by removing some of the magnets. On the videos tab check out the "Adjusting Magnet Strength for Training."

What if I mis-measured?

If you've mismeasured, you may be able to fix it. To make your sash cat door about 1" wider, you may purchase a width extension (or make your own using 1" x lumber). To make your window kitty door insert slightly shorter you may trim the side flanges on the spring loaded adjustment piece with a hacksaw or a jigsaw with a metal cutting blade.

What does custom mean?

Any of the Thermo Sash doors with "Custom" listed means that the door is built to order and therefore it is non-returnable.

Can I get a custom height?

We can only do custom widths, not custom heights.

How much does shipping cost?

Shipping is calculated at checkout.

Warranty

Warranty Type: Lifetime

Duration: Lifetime of the product.

Coverage: Defects in materials and workmanship under standard regular use.

Exclusions:

  • Damage caused by misuse or not using the product as intended.

  • Improper installation.

  • Damage caused by chewing.

View the full Endura Flap warranty policy. 



Customer Reviews

Endura Flap Thermo Sash 3e Cat Doors for Sash Windows

White / 22" - 25" Edit

Endura Flap Thermo Sash 3e Cat Doors for Sash Windows

Size Chart

Flap Dimensions:

6"w x 11”h

The entry way your dog goes through.
flap dimensions
overall panel width

Height to Raise Window

18 1/2"

How high you must raise your window in order to fit the panel into the track.
Flap SizeFlap DimensionHeight To Raise WindowRecommended Pet Height
Small6" w x 11" h18 1/2"9" - 15"

Adjustment Ranges:

  • 22" - 25" Custom Order
  • 25" - 28"
  • 28" - 31"
  • 31" - 34"
  • 34" - 37"
  • 37" - 40"
  • 40" - 43"

 

Pet door has 1" framing, measure your track width to make sure that your window will accommodate the sash.

Final Sales: Adjustment Range 22" - 25" are final sale and cannot be returned. Final Sale products are made to order and will take extra time to ship.

 

Find The Best Pet Door Size For My Pet

A

Pet Height: inches

B

Pet Width: inches

Please fill the above fields.

Flap Material

Flexible

Your Maximum Pet Size

Cats

Installation Instructions

Installation icon Difficulty Easy
Installation icon Steps 04
Installation icon Time Required 0.5 hours
Installation icon Sections 01
Installation icon Flags 01

Parts

  • Sash Window Pet Door
  • Foam Weather Strip
  • Center Post Weather Seal Draft Stopper
  • Screwdriver

Tools

  • Flathead Screwdriver

Please read instructions & notes thoroughly before installation.

Step 1 Release Spring Mechanism

  • Loosen the width adjustment locks at the end of the pet door insert with the screwdriver. This allows the spring mechanism to move freely from side to side.

Step 2 Check Panel Fit

  • Insert the sash into the window track. Push against the spring mechanism and swing the opposite end into the opposite window track. Gently release. Tighten the width adjustment locks.

Step 3 Apply Weatherstripping

  • Remove panel from window track.
  • Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the sash, pressing to ensure it adheres. Install on both the top and the bottom. Trim to fit with scissors.

Step 4 Mount Seal Draft Stopper

  • Mount the Center Post Weather Seal Draft Stopper. This strip prevents air from leaking between the window frame when raised to accommodate the sash. Trim to fit with scissors.
  • Put the panel back into the window track. Tighten width adjustment locks.

Switch the Side of the Flap

You can switch which side of the sash panel the pet door flap is on to best fit your home.

Step 1

  • Remove the screws on the top and bottom closest to the edge of the pet door. Then slightly loosen the screws closest to the glass. Next, slide off the side piece, then the flap assembly.

Step 2

  • Rotate the flap assembly (essentially flipping it upside down) then slide it back in. Make sure the locking cover is on the same side as the width adjustment locks.

Step 3

  • Replace the end spacer and screws.

LOCKING YOUR WINDOW

For a permanent lock, install a wood screw in the track immediately above the window on both sides. You will no longer be able to raise the window. For a temporary lock, place a removable wooden dowel or Charley bar in either track above the window, shown in Detail 1.

HEIGHT OF YOUR WINDOW

Make sure you place steps or ramps leading to your pet’s door at a height that works! When they go through the flap, the top of the flap should be at least 1" (2,5 cm) higher than the top of their back. Watch your pet and adjust as needed to keep them comfortable.

Videos

How to Measure Your Sash Window for a Pet Door





Design of the Endura Flap





Adjusting Magnet Strength for Training





Leaf Blower Test


FAQ

What do I need to know/measure before I order?

First raise up your window and check that it can go up far enough to be left with an opening 18 1/2" high. Next measure the width of the track from left to right, including going inside the track on both sides. Last measure how wide the track is that the window slides in (needs to be at least 1")

How wide does the track have to be for the Thermo Sash 3e to fit?

Track width needs to be at least 1" thick.

Can I choose what side the door is on?

It comes standard on the left, if you are looking from the inside of the house. You can switch it to the other side if you need and that only requires a screwdriver.

Will this door be good for more extreme weather?

The Thermo Sash 3e has the Endura Flap which is far better in sealing and durability than other models. Dual pane lo-e glass offers superior insulation value. Therefore, the Thermo Sash will be a much more reliable and longer lasting option then the more inexpensive options.

Is it possible to make one that fits a window smaller than 22"?

We can, the only thing is that we would not be able to use glass so there would be quite a bit of aluminum and some customers are not happy with the aesthetics. This would also fall under the custom and non-returnable category.

My cat is having a hard time opening the flap is there something I can do that would make it easier?

You can by removing some of the magnets. On the videos tab check out the "Adjusting Magnet Strength for Training."

What if I mis-measured?

If you've mismeasured, you may be able to fix it. To make your sash cat door about 1" wider, you may purchase a width extension (or make your own using 1" x lumber). To make your window kitty door insert slightly shorter you may trim the side flanges on the spring loaded adjustment piece with a hacksaw or a jigsaw with a metal cutting blade.

What does custom mean?

Any of the Thermo Sash doors with "Custom" listed means that the door is built to order and therefore it is non-returnable.

Can I get a custom height?

We can only do custom widths, not custom heights.

How much does shipping cost?

Shipping is calculated at checkout.

Warranty

Warranty Type: Lifetime

Duration: Lifetime of the product.

Coverage: Defects in materials and workmanship under standard regular use.

Exclusions:

  • Damage caused by misuse or not using the product as intended.

  • Improper installation.

  • Damage caused by chewing.

View the full Endura Flap warranty policy.