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Thermo Sash 3e Pet Door for Sash Windows

37 reviews
Regular price
$419.99
Sale price
$419.99
Unit price
per 
White
Brushed Aluminum
Bronze (Very Dark Brown)

  • Durable and insulating pet door for windows
  • Dual-pane, Low-E glass and sturdy aluminum framing
  • Energy-efficient flap design keeps home insulated
  • Various flap sizes, colors, and adjustment ranges to fit your pet and your window
  • Strong and sturdy Locking Cover included to secure your home and pet
  • Tool-free installation, perfect for renters and vacation homes
  • 10-14 Day Delay in Shipping for White and Bronze frames
Extreme Weather Resistance Extreme Weather Resistance
Install Multiple Install Multiple
Tool-Free Installation in Minutes Tool-Free Installation in Minutes

Product Details

  • Highly insualting flap with a complete magnetic seal, designed to stay closed in winds up to 50mph
  • Complete magnetic sealdesigned to stay closed in winds up to 50mph
  • Polyolefin polymer flap keeps your home comfortable in temperatures between -40 and 110℉
  • Dual-pane, LoE glass gives you extra insulation for your home, pairs perfectly with newer energy-efficient windows
  • Four sizes available to fit cats to large breed dogs
  • Fits all vertical sliding sash window widths with a track width of at least 1"
  • Draft stopper and weatherstripping included for extra insulation and weather resistance
  • Easy, tool-free installation in a matter of minutes

 

Need help Installing? Take a look at our Thermo Sash Installation page.

Size Chart

Flap SizeFlap DimensionHeight 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"

For your adjustment range, you need to measure the length of your sash window track from the furthest left to right. The adjustment range of your pet door should ideally have your track length in the middle. Custom orders are subject to special restrictions. The following adjustment ranges are available:

  • 22"– 25"
  • 25"– 28"
  • 28"– 31"
  • 31"– 34"
  • 34"– 37"
  • 37"– 40"
  • 40"– 43"

Additional Information

Frame Material

Aluminum

Track Width Minimum

1"

Flap Thickness

7/8"

Warranty Period

Lifetime

Locking Cover Material

Molded ABS Plastic

Climate Suitability

Severe 4-Season

Ability to Lock Flap

Yes

Can Be Installed In

Sash Windows

Sealing Value

Very High

Installation Instructions

PARTS & TOOLS

1x Window pet door

1x Foam Weather Strip

1x Center Post Weather Seal Draft Stopper

INSTRUCTIONS 

Step 1: Loosen the thumbscrews at the end of the sash. This allows the spring mechanism to move freely side to side.

Step 2: 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 thumbscrews.

If the pet door sits properly, remove the pet door to put on the foam weather-stripping in step 3.

Step 3: 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 the top and the bottom. Trim to fit with scissors.

Step 4: Mount the draft stopper vinyl weatherstrip. This strip prevents air from leaking between the window frame when raised to accommodate the sash. Trim to fit with scissors.

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.

SWITCH SIDE OF FLAP

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. 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 thumbscrews. Replace the end spacer and screws.

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.

 

Replacement Parts and Accessories

 

 

Videos

Installing a Thermo Sash 3e


How to Measure Your Door for a Sash Window Pet Door


Variable Magnetic Resistance


Replacing the Flap in the Sash Pet Door


Switching Flap Sides


Wind Test

FAQ

Does the Thermo Sash have an adjustable height?

No, the unit’s height is determined by the height of the pet door.

If my window is not ground level, can I still install a dog door?

Yes. There are many creative ways to give your dog access to the window, including installing steps or a ramp on both sides of the window.

Can I change which side (left or right) the flap is on?

Yes, you can switch which side of the panel the pet door is on. You start by removing the screws on the top and bottom, then sliding the flap assembly out. Once it is removed you simply flip it upside down and slide it right back in. Next you put the screws back in, tighten them all down and you're finished. You'll want to make sure the thumb screws and locking cover are on the same side.

Is the Thermo Sash available in sizes smaller than the 22" wide?

You can make it 3/4" inch smaller by trimming the spring loaded piece on the right side of the panel. If this is not enough, we may be able to make a custom width with less or no glass. Please contact our customer service team with your specific needs for us to review the possibility.

How high do I have to raise my window in order to install the Thermo Sash?

It can vary based on the size of your pet door:

  • Small is 19"
  • Medium is 23"
  • Large is 27"
  • Extra Large is 31"

 

How wide must the window track be to accommodate the Thermo Sash 3e?

For installation, your window track must be at least 1 inch wide.

I ordered the wrong size. Is there a way to make my panel bigger?

If your door is too short, you can order the patio panel height extension to add additional height.

Which of the Thermo Sashes are considered custom and are not returnable?

All Extra Large pet door sashes and any pet door size in a sash width with a 22"-25" adjustment range are considered custom and are not returnable.

What makes the Endura thermo sash so great?

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.

Warranty

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.

Customer Reviews

Customer Reviews
4.8 Based on 37 Reviews
Write a Review

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
D
07/26/2017
Diane
Amazing Pet Door!

My dog loves her pet door, I love that it is high quality, nice looking, easily installed and fairly insulated from the Texas heat and as a Realtor, I love that it is not permanant and won't leave any evidence of ever being in the window.

J
03/15/2017
Joseph
Expensive but fantastic

I was skeptical, but I think it's definitely worth having a good product.

KL
03/15/2017
K. LaValle
happy kitty. works as advertised. yes you can swith the door to the other side.

very happy. had a little difficulty getting the screws out to switch the opening to the other side as they were in extremely tight. i also had to move one of the magnets on the bottom of the flap because it shifted during shipping and the door seal was not quite right. works great & i have a very happy kitty. i found out how to do these two things online. really easy to do, if you know how. i would ask the company to include the magnet adjustment & door switching in their general documentation that ships with the door. i did have to modify the metal edge of my window frame to allow clearance for the door cover to slide up & down. we used a dremel. this is a permanent modification to the window, so might not be the best solution for a renter. i have tried several kitty-door solutions & would return them. so far, this one is a keeper.

A
09/10/2016
anneengland
Perfect Solution!

We've had this pet door for almost 2 years now and it is wonderful! We have a telescoping ramp on the outside and a smaller plastic ramp inside for our older dog. Texas winds, hail & rain do not affect it - stays tightly closed, yet easy for our dog to go in or out. Less expensive than a new back door, as houses here all have lots of windows floor to ceiling and glass pane back doors. A great investment, and if we ever move, it is removable and reusable!

K
05/08/2016
Krisa
Superb

Quality exceeded my expectations. Highly recommend.

Thermo Sash 3e Pet Door for Sash Windows

22" - 25" / White / Small Edit

White Thermo Sash

Size Chart

Flap SizeFlap DimensionHeight 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"

For your adjustment range, you need to measure the length of your sash window track from the furthest left to right. The adjustment range of your pet door should ideally have your track length in the middle. Custom orders are subject to special restrictions. The following adjustment ranges are available:

  • 22"– 25"
  • 25"– 28"
  • 28"– 31"
  • 31"– 34"
  • 34"– 37"
  • 37"– 40"
  • 40"– 43"

Frame Material

Aluminum

Track Width Minimum

1"

Flap Thickness

7/8"

Warranty Period

Lifetime

Locking Cover Material

Molded ABS Plastic

Climate Suitability

Severe 4-Season

Ability to Lock Flap

Yes

Can Be Installed In

Sash Windows

Sealing Value

Very High

track width minimum

1"

warranty period

Lifetime

Installation Instructions

PARTS & TOOLS

1x Window pet door

1x Foam Weather Strip

1x Center Post Weather Seal Draft Stopper

INSTRUCTIONS 

Step 1: Loosen the thumbscrews at the end of the sash. This allows the spring mechanism to move freely side to side.

Step 2: 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 thumbscrews.

If the pet door sits properly, remove the pet door to put on the foam weather-stripping in step 3.

Step 3: 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 the top and the bottom. Trim to fit with scissors.

Step 4: Mount the draft stopper vinyl weatherstrip. This strip prevents air from leaking between the window frame when raised to accommodate the sash. Trim to fit with scissors.

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.

SWITCH SIDE OF FLAP

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. 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 thumbscrews. Replace the end spacer and screws.

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.

 

Replacement Parts and Accessories

 

 

Videos

Installing a Thermo Sash 3e


How to Measure Your Door for a Sash Window Pet Door


Variable Magnetic Resistance


Replacing the Flap in the Sash Pet Door


Switching Flap Sides


Wind Test

FAQ

Does the Thermo Sash have an adjustable height?

No, the unit’s height is determined by the height of the pet door.

If my window is not ground level, can I still install a dog door?

Yes. There are many creative ways to give your dog access to the window, including installing steps or a ramp on both sides of the window.

Can I change which side (left or right) the flap is on?

Yes, you can switch which side of the panel the pet door is on. You start by removing the screws on the top and bottom, then sliding the flap assembly out. Once it is removed you simply flip it upside down and slide it right back in. Next you put the screws back in, tighten them all down and you're finished. You'll want to make sure the thumb screws and locking cover are on the same side.

Is the Thermo Sash available in sizes smaller than the 22" wide?

You can make it 3/4" inch smaller by trimming the spring loaded piece on the right side of the panel. If this is not enough, we may be able to make a custom width with less or no glass. Please contact our customer service team with your specific needs for us to review the possibility.

How high do I have to raise my window in order to install the Thermo Sash?

It can vary based on the size of your pet door:

  • Small is 19"
  • Medium is 23"
  • Large is 27"
  • Extra Large is 31"

 

How wide must the window track be to accommodate the Thermo Sash 3e?

For installation, your window track must be at least 1 inch wide.

I ordered the wrong size. Is there a way to make my panel bigger?

If your door is too short, you can order the patio panel height extension to add additional height.

Which of the Thermo Sashes are considered custom and are not returnable?

All Extra Large pet door sashes and any pet door size in a sash width with a 22"-25" adjustment range are considered custom and are not returnable.

What makes the Endura thermo sash so great?

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.

Warranty

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.

Customer Reviews

Customer Reviews
4.8 Based on 37 Reviews
Write a Review

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
D
07/26/2017
Diane
Amazing Pet Door!

My dog loves her pet door, I love that it is high quality, nice looking, easily installed and fairly insulated from the Texas heat and as a Realtor, I love that it is not permanant and won't leave any evidence of ever being in the window.

J
03/15/2017
Joseph
Expensive but fantastic

I was skeptical, but I think it's definitely worth having a good product.

KL
03/15/2017
K. LaValle
happy kitty. works as advertised. yes you can swith the door to the other side.

very happy. had a little difficulty getting the screws out to switch the opening to the other side as they were in extremely tight. i also had to move one of the magnets on the bottom of the flap because it shifted during shipping and the door seal was not quite right. works great & i have a very happy kitty. i found out how to do these two things online. really easy to do, if you know how. i would ask the company to include the magnet adjustment & door switching in their general documentation that ships with the door. i did have to modify the metal edge of my window frame to allow clearance for the door cover to slide up & down. we used a dremel. this is a permanent modification to the window, so might not be the best solution for a renter. i have tried several kitty-door solutions & would return them. so far, this one is a keeper.

A
09/10/2016
anneengland
Perfect Solution!

We've had this pet door for almost 2 years now and it is wonderful! We have a telescoping ramp on the outside and a smaller plastic ramp inside for our older dog. Texas winds, hail & rain do not affect it - stays tightly closed, yet easy for our dog to go in or out. Less expensive than a new back door, as houses here all have lots of windows floor to ceiling and glass pane back doors. A great investment, and if we ever move, it is removable and reusable!

K
05/08/2016
Krisa
Superb

Quality exceeded my expectations. Highly recommend.

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