Customer Service: 1.800.826.28717am-4:30pm PST

Pet Doors For Windows

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.

Read FAQ's about Pet Doors for Windows

Read more about Pet Doors for Windows below >>

Grid List

Set Descending Direction

8 Item(s)

per page

Grid List

Set Descending Direction

8 Item(s)

per page


Windows that slide sideways are actually "short" sliding glass doors!

The best and only solution is a "custom height undersized" patio pet door. Order a Thermo Panel IIIe™ built custom height undersized.

Special Notices

For Windows FAQ

Restocking Fees


    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 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.

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

    A. The installation is very simple. The lower window is raised and the pet door unit is positioned in the track beneath the window. Then the window is closed on the pet door sash.

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

    • 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.

    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 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?

    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. The window can't be raised when the dowels are in place but can be raised when the dowels are removed.

    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 one that interests you has this.

    What about the screen?

    It's got to come off!

    Q. Ouch! These are expensive. Any way to make my own?

    A. Sure. Here's how (this is 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 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 done.


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

    Key points

    • 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.
    • Sash window pet doors don't generally come with locks for the sash window. However, there are two simple suggested methods for locking the window after you install the pet door:
    • For a permanent lock, simply place a wood screw above the window in both tracks.
    • If you want to be able to open the window, cut two wooden dowels and place them in the window tracks above the window.

    Either way the window cannot be raised from the outside.