Ideal "Fast Sash" Pet Doors For Windows

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  • Dog or cat door for sash windows
  • Sizes available for cats and small to medium size dogs
  • Tool-free installation
  • Designed for mild climates
  • Available in white only

This sash window pet door is a hassle-free design that gives your pet the freedom to go in and out without interrupting your day. The high-quality panel and vinyl flap allow your small dog or large cat to go out with ease. The spring-loaded design allows for easy installation and removal without the need for any extra tools. With flap sizes ranging from small to extra-large, this flexible, lightweight design accommodates pets of varying sizes so that you only have to make a one-time purchase. It functions as a sash window cat door, flexible cat flap, or small to mid-sized dog door. 


  • The spring-loaded, adjustable design comes in five adjustment ranges for multiple window sizes:
    • 23" - 28" (not available for extra-large)
    • 27" - 32"
    • 33" - 38"
    • 37" - 42"
    • 45" - 50"
    • The 33" - 38" design is our standard size; the other size ranges are custom-made and final sale.
  • Flap sizes range from small to extra-large. Select the size based on the measurements of the width between your pet's shoulders and their height from the back (just behind the head) down to the bottom of the chest.
  • White, aluminum frame fits into tracks between 7/8" and 1 1/4" wide.
  • Door consists of a clear, vinyl flap that pets can easily see-through.
  • Cat Door Window Insert single-pane glass is designed for moderate climates.
  • Comes with a locking cover that slides in from the top of the inside of the window. This feature is great for times when you need to keep your pet either indoors or outdoors.  Make sure your window will accommodate for sliding from the top and does not have a lip that will block this from sliding.
  • Sturdy, insulated design contains a magnetic strip to prevent outside air from entering or escaping.
  • Does not require any replacements or modifications to the initial window design.


  • Easy installation and removal cater to homeowners, renters, and those who want a semi-permanent or temporary fixture.
  • The white frame matches well with common window features, so there is no need for any extra aesthetic retouches.
  • The lightweight flap material allows pets of varying sizes to enter and exit through a larger flap size.
  • The product comes with well-written instructions for installation. You can find a step by step video tutorial further down this product page.
  • The clear, flexible flap material promotes a simple, straightforward, and easy adjustment period for your pet.
  • No more pawing or scratching on windows and doors means less cleaning and repairs.

Size Chart

Flap SizeFlap DimensionHeight to Raise Window
Small5" x 7"13 3⁄4"
Medium7" x 11 1⁄4"17 7⁄8"
Extra Large10 1⁄2" x 15"21 15⁄16"


Do not know which flap size to get? Here is a measurement guide to help you out

Adjustment Ranges

  • 23" – 28" Custom Order (not available for Extra Large)
  • 27" – 32" Custom Order
  • 33" – 38"
  • 37" – 42" Custom Order
  • 40" – 45" Custom Order
  • 45" – 50" Custom Order


Final Sales:  Adjustment Ranges other than 33" – 38" are final sales and cannot be returned. Custom positioning options are also final sale and cannot be returned.


Additional Information



Frame Material

Extruded Aluminum

Flap Material


Flap Colors


Flap Thickness


Dual or Single Pane

Single Pane 1/8" Thick

Warranty Period

1 year

Return Period

30 days

Locking Cover Material

ABS Plastic

Flap Type

Single Flap

Your Maximum Pet Size

Cats, Large Cats, Small Dogs, Medium Dogs

Climate Suitability

Mild or Utility

Type of Window

Sash (Up & Down)

Flap Design

Single, One Part, Flexible, Thin Flap

Ability to Lock Flap

Separate Locking Cover-Loads from Top

Can Be Installed In

Sash Windows

Sealing Value


Wind Resistance


Replacement Flaps Available


Insulation Value



How to Measure Your Sash Window for a Pet Door

The Ideal "Fast Sash" Installation


What three things do I have to know/measure when choosing a pet door for sash window?

For the Ideal Fast Sash Pet Door for windows, you need to check three things: track width, height (so you can raise the window), and how wide the window is from left to right.

Are the Ideal Sash Windows made with dual-pane glass?

No, these aluminum sash window inserts are made with a thick single pane glass.

Can I lock the Ideal Fast Sash for Windows?

Yes, it comes with a locking cover that slides in from the top of the sash window. You will need to double-check to make sure that there is no lip sticking out on the frame that closes down on top of the sash pet door because that would get in the way of sliding in the cover. 

Note: It is not a 4 way lock as the locking cover effectively blocks both directions of travel.

What is the return policy for the Ideal Fast Sash?

Return period is within 30 days, and there is a 15% restocking fee. However, adjustment ranges other than 33" - 38" are final sales. Window mount pet door sashes where the cat door has been ordered to the right or to the left.

How do I measure my window?

You will want to measure the width of your window track to determine the adjustment range you need; measure from deep inside the window track on the left to deep inside the window track on the right.

How wide does the track have to be for the Ideal Sash Windows?

The track needs to be at least 7/8" wide for the Ideal Sash Windows. If your track is thicker than 1 ¼" inches, you may consider putting in shims in the window frame to make the sash more stable in the frame.

If my window is a little smaller than the adjustment ranges for the Ideal Sashes, is there anything I can do?

You can trim the flanges using a jigsaw with a metal cutting blade or a hacksaw. On these models, you can trim both sides if you need to, which gives you about 1-¾" of wiggle room for mismeasures.

Is this well insulated? How weatherproof and energy-efficient is this?

The door features single pane glass, which is optimal for moderate or less extreme climates. We recommend weatherstripping on every installation.

Are there any screws or permanent type of attachments? I would like to remove it in the winter. 

There is nothing permanent about it. The the window sash cat door uses a spring-loaded design to fit windows of almost any size, and is perfect for temporary or semi-permanent installation. Installing the door requires no tools.

Is this a vinyl flap or a hard plastic cat door? 

The cat flap door is a clear vinyl, which is designed to be easy to use for your pets. The flexible flap makes it easy as a large cat door. Some small cats may have more trouble with its weight.

I need the larger width of 33" to 38", but that description says the door opening is smaller. My window measures 32.5". One size listed goes up to 32", next size is 33+". Which of these, if any, will work for me?

If you go with the 27" - 32" range, you can add space on either side using shims. If you go with the 33" - 38" range, and that is too big, up to 1" can be trimmed off of either side of the door to make it fit.

How do you teach your cats to use the Cat Door For Windows?

Window sash cat doors can be a little difficult for timid pets at first. Encourage your cats to go through the door by holding the flap open for them at first, and beckoning them through with the offer of treats on the other side. Repeat the process several times while gradually lowering the flap, so it begins to graze their back as they pass through and they get used to using the flap itself. For the most part, if there is a platform on the other side of the window, training is the same as training them on an exterior door, interior door, or even pet screen door. Most flap openings operate the same way.

Can the cat door be positioned for a left or right configuration?

The sash comes standard with the flap in the center position. However, you can order a custom-mount door, so it is on the left or the right. You may wish to do this if you already have a DIY cat patio or decor on your window.

Wait, is this really only for cats?

Even though most customers use this as a window sash cat door, larger pets can use it too. A dog door for windows would need to be ordered in one of the larger sizes, just make sure that your window opens up high enough to get it in the track. This Ideal Pet Products panel's dimensions only go up to 10.5" w x 15" h, so it is really important to measure your pets.

Is this one of the Vinyl Sash Window Pet Doors? 

The sash is actually aluminum, but it can be used in vinyl windows as long as all the dimensions line up.

Will this work in my vinyl window?

It will. There are many window manufacturers with different designs. You may need to shim or install a stop to ensure the pet door is securely installed in your window. We encourage the use of weatherstripping, regardless of window design.

Is this panel electronic or automatic?

No, this is solely a manual flap. We do have options for microchip cat doors, collar tag door flaps, and an electronic cat door for horizontal sliding windows, as well as brands like SureFlap, CatMate, and other Ideal Pet Products aluminum sash windows. You can find them all on our page on Pet Doors for Windows.



The new and revised warranty that follows this disclaimer supersedes any and all previous warranties of whatever nature or description, whether express, implied or set by law. Any unexpired warranties shall now be governed by the terms of the new warranty for the duration of the existing warranty’s unexpired term.

One Year Warranty:

Ideal’s pet doors are very durable and with the proper care will provide many years of service for you and your pet. Thank you for selecting Ideal for your pet door. However, please be aware the pet doors are not waterproof against inclement weather or any excessive water exposure. The one year warranty set forth below applies to Ideal’s pet door(s).

This product has a One Year Warranty from the date of the purchase of the product to be free of manufacturer’s defects in workmanship and materials. This express One Year Warranty is limited only to the original purchaser of the product and is non-transferable. Satisfactory proof of purchase must be provided to the manufacturer for this one year warranty to apply. In that case, the manufacturer will replace at no charge to the purchaser the defective part(s). No refunds will be provided to the purchaser. No service contract is being provided under this One Year Warranty. Proof of purchase so that the One Year Warranty may be honored must be made to:

Ideal Pet Products, Inc.

24735 Avenue Rockefeller

Valencia, California, USA 91355

Attention: Warranty Department

(661) 294-2266 / 1-877-IDEALPET (433-2573)

Any and all implied warranties are expressly disclaimed and of no force or effect. These warranties include, but are not limited to, the implied warranties of merchantability, implied fitness for any intended purpose, and any warranties under the California Song-Beverly Consumer Act.

This One Year Warranty is void if the damage is due to improper installation, intentional misuse or abuse, repairs by anyone other than the manufacturer, the failure to follow manufacturer’s instructions, or if the product is being used for commercial purposes. Purchaser assumes all risks and liabilities for the misuse or abuse of the product, the commercial use of the product, or the failure to follow the manufacturer’s instructions.

This One Year Warranty only applies if the product is used for domesticated animals. The Manufacturer, Ideal, is not responsible and shall not have any liability for any damage to or defects caused by acts of God, criminal activity, dog abuse including, but not limited to chewing on the door, lightening, abuse, alteration, trespassing, children’s use of the product, unauthorized access, entry by non-domesticated or “stray” animals, or any other unintended use or misuse of the product.

The Manufacturer, Ideal, disclaims and excludes any liability for incidental, consequential, punitive, general, special, or other damages arising out of or connected with the purchase, use, or misuse of the product or concerning any warranty herein.

This One Year Warranty shall be governed by the laws of the State of California, USA. Venue shall be with the Los Angeles Superior Court, North Valley District.


This product, or any of its accessories, parts, or attachments may not prevent adults, children, animals, insects, or objects from passing through or using the opening created by the product.

Ideal Pet Products will not be liable for any unintended or accidental usage, misuse, abuse, criminal conduct, water intrusion, acts of god, damages or injuries occurring or accruing from the use of this product except in strict accordance with Ideal's One Year Warranty accompanying the sale of this product to the original purchaser.

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