Pet Doors For Windows

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Pet Doors for Sash Windows and Sliding Windows

If you have a sash window that slides up and down, or a sideways sliding window you're in luck! A window pet door is a quick and easy way to give your pet access without having to install a dog door or cat door in your doors or walls.


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Some are available with dual pane glass and high quality flap designs. These will be more expensive but will provide much better performance in extreme temperatures Sash window pet doors with single pane glass with cheaper flaps will not perform so well but will be less expensive.

Is the window close enough to the floor that my pet can easily access the pet door? If not, do I have a way to put steps or a ramp to make it accessible? The same consideration applies to the outside of the window as well, of course.

Will the window open high enough to accommodate the sash pet door panel that I am considering? Is the sash window pet door that I am considering available in a width that will fit my window side-to-side? Note that the measurement is the full width inside the track. Is the track wide enough to accommodate the frame of the sash window pet door I'm considering?

If you want the window permanently locked, after installing the sash window pet door simply install a screw part way in just above the lower window in both tracks. The window can't be raised from the outside and the screws cannot be removed from the outside either. If you want to be able to raise the window on occasion (for cleaning the outside, say)the simplest way is to cut two dowels to stand inside both window tracks just above the window and reaching to the window frame. The window can't be raised when the dowels are in place but can be raised when the dowels are removed.

Raise the window and measure the full width including into the track on both sides. Be sure that the pet door you choose has the proper adjustment range for your window. Second, be sure the window can be raised high enough to accept the pet door.

Finally, some of these models include a locking cover that needs to slide down a track over the flap. If you're purchasing one of these, be sure you've got enough clearance above the pet door for the locking cover to slide straight up. There must be no overhang or 'lip' in the way. Check your windows to see if they are single pane glass or dual pane glass. If you have dual pane and live in a more severe climate area, you may wish to order a dual-pane, insulated glass pet door. Best way to check? Put a finger on both sides of the glass. If they look like they're touching you've got single pane glass. If they stop about 1/2" apart, you've got dual-pane.

Do you have a question that wasn't answered? If you do, please email it to us at customerservice@petdoors.com


Q: What is meant by “Sash Window?”

A: A sash window, or ‘double-hung’ window consists of two window units, one above the other, in separate tracks. The bottom unit slides up and down in the inside track and in the case of double-hung windows the top unit may slide in the outside track as well. There may be a locking device in the center where the two window frames meet.

Sash Window


Q: How is a pet door installed in a sash window?

A: This installation can be very simple, and depending on the type of track may require no tools. The lower window is raised and the pet door is positioned in the track beneath the window. Then the window is closed down on top of the pet door sash.

Sash Window

Q: What are the major types or styles of sash window pet doors?

A: Some are available with dual pane glass and high quality flap designs. These will be more expensive, but will provide much better performance in extreme temperatures. Examples of these are the  Thermo-Sash IIIe and Hale “Omni” for Sash Windows.  Sash Window pet doors with single pane glass and thinner flexible vinyl or polycarbonate rigid flaps will not perform as well, but are a more economical choice if you are on a budget. If this less expensive model is what you are looking for we offer the  Ideal “Fast Sash” and Ideal “Cat Sash”.

Q: What are some specific points that I should think about when considering a sash window pet door?

A: Is the window close enough to the floor that my pet can easily and safely access the pet door? If not, do I have a way to put steps or a ramp to make it accessible? The same consideration applies to the outside of the window as well, say if your window leads out to a deck where they would have to step up or down to get through. Is insulation quality a major concern when choosing your sash window pet door? Or is keeping other animals out a bigger issue?  The window track width is also important, as it has to be wide enough to accommodate the framing of the sash window.  Most sash windows will require a track that is at least 1” wide, however the Hale Omni Sash can be modified to fit widths down to ½”.  Knowing how high you can raise the window in order to install the door is another piece of information you will need.    

Q: Can I lock my window with the pet door installed? What kind of lock will the pet door include?

A: A sash window pet door may not include a lock at all as there are two very simple methods for locking the window. If you want the window permanently locked, after installing the sash window pet door simply install a screw part way in just above the lower window in both tracks. The window can't be raised from the outside and the screws cannot be removed from the outside either.

If you want to be able to raise the window on occasion (for cleaning the outside, say)the simplest way is to cut two dowels to stand inside both window tracks just above the window and reaching to the window frame. These will block the window from being able to be moved upward! The window can't be raised when the dowels are in place but can be raised when the dowels are removed.

sash window

Q: When I raise my window to accommodate the pet door, I break a seal at the center between the two window sections. Any way to seal this up again?

A: Your sash window pet door should come with weather strip designed to seal this gap up again.  Be sure the particular pet door you're interested in has this included with the purchase.  We include this item, also called a draft stopper or center post weatherstrip, with our Thermo Sash IIIe.

Q: What will I have to do with the screen on my window that I want to install a pet door in?

A: The screen must come off in order to allow your pet to enter and exit freely.  Your screen should be held in a frame that can pop off the outside and you can store for future use.  

Q: Ouch! These are expensive, any way to make my own?

A: Sure. Here’s how (Beware: It’s going to sound harder than it is)

Start with a piece of plywood or Lexan cut tall enough to accept the pet door and wide enough to extend to a shade less than half the depth of each track. This dimension will allow the panel to be inserted into the track. When one end is all the way in, the other end will just clear the opposite track wall. Then you center so that both ends protrude into the track half way.

Run adhesive-backed weather-strip along the top and bottom of your panel to ensure a tight seal. From the outside, drill a hole in each corner at an angle into the window track. Use a wood or metal screw in each corner to hold your material in place. Install a door mount type pet door of your choice into the wood or Lexan panel you’ve fastened in place.

If necessary, shim around the hole to the thickness required by the pet door. You’ll want to install the pet door before fastening the panel into the track. If wood, paint to match your decor. Lexan looks like glass so no painting is required. Close the window on your pet door and decide if you need a lock (see above).

If the opening of your window has broken the seal between the two window sections, weather-strip that gap. You can find the weather-stripping you need at pet door weather-stripping.

Bingo! You’re all done!

Q: Are the Ideal Sash Windows made with dual pane glass?

A: No, they are made with ⅛” thick single pane glass.

Q: Can I lock the Ideal Fast Sash for Windows?

A: 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.

Q: Can I switch the side the pet door is on? How would I do that with the Ideal models?

A: You have to specify on the order where you want the door installed. You should really make sure this is where you want the door to be because once the Ideal sash is built with the door to the left or right it cannot be changed since it is a custom order and therefore non-returnable. Another issue is that the door will not be all the way to one side in the instance of the Ideal Fast Sash.  This is because the thumb screws that adjust the spring load on the sides would interfere with the closing cover, so it would end up looking something like this:

Ideal Fast Sash

Q: Can I switch the side the pet door is on with the Thermo Sash IIIe? How?

A: Yes you can switch the side the pet door is on. You can 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.  

Q: Can you make a Thermo Sash smaller than the 22" adjustment?

A: Not generally if you want glass in it.  What you can do is trim down the spring loaded piece on the side, to give you an extra ¾” of compression so that you can get it down to 21-¼”.  If this is still not enough then give us a call with your dimensions because we might be able to build one for you that only uses metal and not glass.  This may not seem as nice aesthetically, but it will get the job done and you’ll be very happy with the Endura flap choice.    

Q: Do I need tools to install the Hale Pet Door Omni Sash?

A: Yes, you will need a wrench in order to install the Hale Omni Sash as that is used to finally tighten the adjusting nuts and hold it in place.  This is included in the kit that comes with the Omni.  If you want, and this is optional, you can drill a screw into the frame of the window which would make it so that you can’t pull the window away from the pet door.  This would make it more of a semi-permanent installation.

Q: Do I need tools to install the Thermo Sash?

A: No, there are no tools required to install the Thermo Sash, but just like with the Hale you can drill in a screw above the sliding window for security.

Q: Do the Ideal Sash Windows come in colors?

A: The Ideal Sash window only comes in white.

Q: Do you have any pet door sashes that are electronic?

A: Yes, the Ideal “E” Cat Electronic Cat Door  is electronic, but it is for cats only and it only controls one way (magnetic).  This means that it wouldn’t be a good choice if you wanted to keep one cat inside and let another in and out.  Also it isn’t raccoon proof, because with the magnetic doors they can get their little nails under the flap from the outside and pull it backwards, simulating something going out, and sneak inside under the flap.

Cat going out of pet door

Ideal “E” Cat Electronic Cat Door

Q: Do you offer different colors for sash windows?

A: We do in the more insulated models.  For the Thermo Sash we have white, bronze, and satin (aluminum) and in the Omni we have the same options and an additional choice of Arizona Beige.

     Thermo SashHale Omni Sash Window

                       Thermo Sash                                Hale Omni Sash Window




Do you have a question that wasn't answered? If you do, please email it to us at customerservice@petdoors.com