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Thermo Sash 3e Cat Door for Sash Windows

Thermo Sash 3e Cat Door for Sash Windows

Regular price
$429.99
Sale price
$429.99
Unit price
per 
White
Dark Bronze/Black
Brushed Aluminum

  • Durable and insulating pet door for windows
  • Dual-pane, Low-E glass for energy efficiency and reduction of harmful UV and infrared light
  • Sturdy aluminum framing
  • Various colors and adjustment ranges to fit your pet and your window
  • Strong Locking Cover included to secure your home and cat
  • Easy to install and doesn't require semi-permanent installation, perfect for renters and vacation homes
Holds Up to Harsh Weather Holds Up to Harsh Weather
Cats Love it Cats Love it
Tool-Free, Five Minute Installation Tool-Free, Five Minute Installation

Product Details

  • Highly insulating flap with a complete magnetic seal, designed to stay closed in winds up to 50mph
  • Polyolefin-based polymer flap keeps your home comfortable in temperatures between -40 and 110℉
  • Dual-pane, Low-E 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"
  • Three color options including white, brushed aluminum, and bronze (very dark brown)
  • Includes a draft stopper and weatherstripping for extra insulation and weather resistance
  • Can be installed and removed in seconds due to the spring-loaded design, no tools required
  • 100% made in the USA


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

Size Chart

Flap Size Flap Dimension Height To Raise Window
Small 6" w x 11" h 18 1/2"

Adjustment ranges:

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 returns. Please simulate the opening (open the window, use duct tape to simulate the opening) to be sure this size is appropriate before ordering.

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 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

Tools

  • None

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. 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

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


Additional Switch the Side of the Flap


Wind Test

FAQ

Does the Thermo Sash have an adjustable height?

No, the height of the small sash window unit is determined by the height of the pet door.

Can I still into this dog door into my window if my window is not at ground level?

Yes! You can install steps or a ramp on both sides of the window to ensure your dog has access.

Is there a way to switch which side of the Thermo Sash the flap is on (from the left to the right)?

Yes. Start by removing the screws on the bottom and top og the panel, then sliding the flap assembly out. Then you can simply flip the assembly upside down and slide it right back in. Put the screws back in and tightened them. Make sure the thumb screws and your locking cover are on the same side of the panel.

Is the Thermo Sash available in sizes narrower than 22” wide?

You can make the small sash window panel ¾” smaller by trimming the spring loaded piece on the right side. Otherwise, we may be able to make you a custom unit. Please contact customer service for more details.

How high does my window have to be raised in order to install the Thermo Sash?

It varies based on your pet door size and height:

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

What is the minimum width of the window track needed to accommodate the Thermo Sash 3e?

Your window track must at least be 1” wide.Your window track must be at least 1 inch wide for thermo sash 3e pet door installation.

Is this for sideways sliding windows?

No, this insert is for sash windows, which slide up and down and not side to side. If you have a sideways sliding window, see the Endura Flap Cat Door for Horizontal Sliding Windows.  

Which 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.

Is this for sideways sliding windows?

No, this insert is for sash windows, which slide up and down and not side to side. If you have a sideways sliding window, see the Endura Flap Cat Door for Horizontal Sliding Windows.  

What makes the Endura Flap better than other pet doors?

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

Thermo Sash 3e Cat Door for Sash Windows

White / 22" - 25" Edit

The Thermo Sash window dog door is aethsetically pleasing and build to last. It comes in a variety of sizes to fit many animals.

Flap Size Flap Dimension Height To Raise Window
Small 6" w x 11" h 18 1/2"

Adjustment ranges:

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 returns. Please simulate the opening (open the window, use duct tape to simulate the opening) to be sure this size is appropriate before ordering.

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

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

Tools

  • None

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. 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

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


Additional Switch the Side of the Flap


Wind Test

FAQ

Does the Thermo Sash have an adjustable height?

No, the height of the small sash window unit is determined by the height of the pet door.

Can I still into this dog door into my window if my window is not at ground level?

Yes! You can install steps or a ramp on both sides of the window to ensure your dog has access.

Is there a way to switch which side of the Thermo Sash the flap is on (from the left to the right)?

Yes. Start by removing the screws on the bottom and top og the panel, then sliding the flap assembly out. Then you can simply flip the assembly upside down and slide it right back in. Put the screws back in and tightened them. Make sure the thumb screws and your locking cover are on the same side of the panel.

Is the Thermo Sash available in sizes narrower than 22” wide?

You can make the small sash window panel ¾” smaller by trimming the spring loaded piece on the right side. Otherwise, we may be able to make you a custom unit. Please contact customer service for more details.

How high does my window have to be raised in order to install the Thermo Sash?

It varies based on your pet door size and height:

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

What is the minimum width of the window track needed to accommodate the Thermo Sash 3e?

Your window track must at least be 1” wide.Your window track must be at least 1 inch wide for thermo sash 3e pet door installation.

Is this for sideways sliding windows?

No, this insert is for sash windows, which slide up and down and not side to side. If you have a sideways sliding window, see the Endura Flap Cat Door for Horizontal Sliding Windows.  

Which 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.

Is this for sideways sliding windows?

No, this insert is for sash windows, which slide up and down and not side to side. If you have a sideways sliding window, see the Endura Flap Cat Door for Horizontal Sliding Windows.  

What makes the Endura Flap better than other pet doors?

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

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