Installing a Dog Door in a Sliding Glass Door

Installing a dog door for your pet doesn't always mean cutting a hole in your door or wall! Dog doors can be easily fitted into existing sliding glass doors with just a few modifications. Sliding door dog doors have many benefits:

  • Minimal modification to existing slider
  • Great option for renters
  • Looks great inside your sliding door
  • Won't increase your energy bill

Keep reading to learn everything you need to know about a dog door in a sliding glass door, including installation!

Border Collie through pet door - install dog door in sliding glass door or wondering how to install a dog door in a sliding glass door?

1. What is a Sliding Glass Door Pet Door?

Commonly known as the patio panel pet door, dog doors in sliding glass doors offer a simple yet effective solution. Learning how to install a doggie door in a sliding glass door is a super easy DIY process, no need to hire a professional! These tips for installing a dog door insert in slider tracks should help guide the process. The dog door you wish to install can be any size so it accommodates your pet. You will no longer have to make a hole through your wall or break a door down when you install a pet door insert in sliding glass door.

When installing a pet door in a glass door, a panel is inserted into the sliding door track. The new panel that is inserted has glass on top and a pet door flap at the bottom. Once you install a doggie door in a glass door, the slider of the door slides in its track against the sliding glass pet door panel. The track for the door is shortened because of the additional panel inserted. Screen doors will still function normally with the doggy door panel inserted.

There are a number of custom options for irregular sliding door track heights. The Dragon Custom Single Flap Panel and Dragon Custom Double Flap Panel are two affordable options. For cats, check out the Custom Whiskers & Windows Sliding Glass Cat Door

Have a vinyl sliding glass door? The Custom Endura Flap Severe Weather Sliding Glass Dog Door is a great option for short vinyl sliding doors. 

You can also have a pet door installed directly into the glass of your sliding glass door

2. Check the Design of Your Door

The first step for sliding glass dog door installation is to check your sliding door and measure the track of your door. You have to see if the track your door is sliding in is a monorail or not. It is a bit easier when the track is not a monorail, as the panel can easily be adjusted. However, if the track of your door is a monorail, you we have monorail adaptors available. The inserted panel forms a partition that divides the whole door into two parts. One being the stationary panel with a pet door, and the other being the pre-existing slider panel of your door.

Sliding glass pet door panels can also be installed in double door sliders. Installation can work the same way. In order for the panel insert to remain secure and stable, you will need to make one of your sliders stationary. In essence, you will only be allowed to slide and walk through 1 of your two sliders.

Sliding door insert for double door slider

2. Measure Your Pet

It’s important that you select the correct flap size for your pet! You don’t want to end up with a dog door that is too small or too big for your pet.

To measure your pet, you should take measurements of the widest part of your pet’s body and add about 2″ to it. For the length, measure how tall your pet is from its shoulder to its feet and add about 1″ to it. These measurements will ensure that the flap is large enough to comfortably let your dog through. It will also ensure that no larger animals from the outside can enter into your home through the flap.

3. Position the Flap on the Door

dog wondering how to install a doggie door in a sliding glass door and cost of glass dog door installation

Next, you should cut a piece of cardboard as a tester that will give you a good idea where you are going to place the flap in your sliding door. You should place the flap in a corner area that will not disrupt the functioning of the sliding door. The spot where you place the flap should also be a convenient spot for your pet to find.

4. Measure the Sliding Door

The next step is to find the height of the door that will match your slider. After you install an additional panel for the dog door, the area of your door is going to decrease. Take the measurements of the door with a tape measure and find measurements for the panel you will install. The size of the panel will also incorporate the width of the flap you are going to install in it. Many brands carry sizes small to extra large to fit pets of all sizes.

After you're done taking all the measurements, you can order a panel with your specifications and the panel of your choice. At Pet Doors, there is an extensive collection of sliding door panels that you can use for your sliding door. Choose the one that fits your style and is okay for your pet.

5. Dry Fit the Panel

Soon after you have ordered the panel, you will receive the same one from Before installing the panel, dry-fit it to see if any corrections are needed. Dry fitting the panel will help you get a good picture of how your door will look like after the modification.


6. Fit the Panel In

Dog watching owner installing a pet door in a glass door

If everything is as planned and the panel you got is perfect, it is time to fit the panel in your sliding door. Place the panel in the bottom track and place it in the spot you want it to. Twist the screws from the bottom part so it is stable and you can position it from the top.

The panel for the sliding door comes with some type of pressure system towards the top end, from where it expands and fits in the height of the track. Mostly, the panels do not require any extra tools to fit. These panels are perfect for vacation home or rentals because they can easily be popped out of the track if you want to remove them! Once you have positioned your panel perfectly, tighten the screws and fix it in the spot so it doesn’t move.


7. Finalize the Installation

Once you fit the panel in your sliding door track, you are almost done with all the work. Install any insulation or any other material that may come with the panel such as weather stripping. Follow the steps carefully and you will have a new patio panel in your sliding glass door.

The addition of a dog door in the sliding glass door is an excellent option for giving your pet outdoor access. Instead of cutting your walls to accomodate a dog door, a patio panel gives your dog the freedom to come and go without all the hassle.

There are many kinds of panels that may be installed in your sliding door, but they all typically follow the same procedure with a few changes. All you need to do is pick the best one for you!

For energy efficiency we highly recommend the Endura Flap Thermo Panel 3e. Manufactured by Patio Pacific, this energy efficient panel features dual pane, low e glass and a high-quality, polyolefin polymer flap. The Endura sliding patio door comes in a wide range of sizes to function as anything from a cat flap in patio doors to a large dog door, depending on which size you select.

Visit to our view our full selection of sliding glass pet doors to choose the option that works best for you and your pet!

Stephen Daily

Written by

Stephen Daily

The Team is dedicated to providing the highest quality pet doors. As dog and cat lovers ourselves, we aim to write about the topics that matter the most to you and your furry friend. If you have any questions, please contact our customer service team. 🐶🐱

The Team is dedicated to providing the highest quality pet doors. As dog and cat lovers ourselves, we aim to write about the topics that matter the most to you and your furry friend. If you have any questions, please contact our customer service team. 🐶🐱


  • Hi Craig,

    I would recommend this option for a 71" slider:

    If you have any questions, please feel free to call us at 1-800-826-2871 or email

    Happy New Year!

    Elizabeth (Staff)
  • Can any of the sliding glass door units be cut down to fit a 71" door?

  • Hi Susan,

    The PetSafe Freedom Panel ( is a great option. It is available in a 76" – 80.5" or 91.5" – 96" range depending on your track height.

    Here’s how to measure track height: Please feel free to contact us at or 1-800-826-2871 if you have any questions!

    Happy holidays!

    Elizabeth (Staff)
  • Hi Laura,

    If the doggy door is wobbling in the track an option is to add a wooden shim next to the panel to fill up the full space of the track and stabilize the panel.

    Another option is to toenail the panel into the track or secure it with L brackets. Toenailing means driving a nail through the panel and the track at a 45-degree angle to attach them.

    Please feel free to contact us at or 1-800-826-2871 if you have any questions!

    Happy holidays!

    Elizabeth (Staff)
  • Hi Jolane,

    Please reach out to us at or 1-800-826-2871 and we will send you the installation instructions for your panel. You can also check out our installation instructions archive here:

    We will also advise you on how to lock your panel, as different brands and models come with different locking mechanisms. Look forward to hearing from you and happy holidays!

    Elizabeth (Staff)
  • Hi Beulah,

    The best sliding pet door for harsh weather is the Endura Flap Thermo Panel: The flap in this panel has accordion-style bellows that will not shrink in the cold, which prevents the gaps on the sides of the flap you mentioned. The flap also has strong magnets lining the sides and bottom of the flap to ensure there are no gaps between the flap and frame.

    I hope this helped answer your question. Please feel to reach out to for further suggestions!

    Happy holidays!

    Elizabeth (Staff)
  • Where can I find a tunnel to attach to the outside of the flap to help keep out cold. There is always space on each side after it gets stretched. Or is there a weather stripping That will work and leave the flap free to swing back and forth.

    Beulah Hancock
  • Hi, I just received a Sliding Glass Pet Door Insert. It didn’t come with any instructions, and I’m not sure where to put the weather strip. I also don’t see a sliding glass door lock, unless it’s just the extra screw I found in the box. None of the videos addresses this. Please advise.

    Jolane Abrams
  • We have a tri door slider that has a middle rail in the frame. We can’t get the doggy door to stay in tightly. Any suggestions?

  • How do you shrink a pet safe doggy door to 96 to 80

  • Hi Victor,

    Yes, once the patio panel is installed, you will still be able to use the sliding door freely. You’ll just want to make sure you have a way to lock the slider with the panel in place (we recommend using a wooden dowel in the track or a charley bar). Please contact us at for any additional questions!

    Grace (Staff)
  • Once the panel with the doggie door is installed can I still go in and out freely? My bbq pit is on the patio, so I need to still be able to use the sliding door regularly.

  • Ì want to buy a pet door panels, but how do Ì find someone to install it. Ì am a widow.

    Vera Entwistle
  • I had one of the doggie doors and it worked fantastic. We just purchased a new home with 8 foot doors, I ordered another one and it will not work as the distance from the rail to one edge is
    1 1/2 inches. I really wish that they would make a wider one

    Ron Dinkel
  • Hi Pat! Thanks for the question. The sliding door pet door panel actually installs into the track in the space between the slider and the frame when your slider is open. So the slider would be secured with a sliding glass door lock or a charley bar (or a rod in the track). If you are wanting to install a pet door in the glass portion of your slider, here is a blog post to explain that process . And here is the link to the product you would be looking for

    If you have any additional questions, please feel free to call us at 1-800-826-2871 or email us at

  • My sliding door has a seal to the door when you close the sliding glass. How do I seal the door off? I’m talking about the seal that goes to the glass , not where it locks to the frame.

  • Hi Renee,

    With a sliding glass door pet door panel, you would have to lock the sliding door from the inside using a c-clamp lock or a charley bar. Most sliding glass panel pet doors come with a locking cover for the pet door as well, so you can lock the opening from the inside.

    If you have any other questions, please don’t hesitate to contact us at!

    Grace Fuh
  • My slider is the main entrance in and out. Can I still go in and out? Can I lock the patio door as well as the dog door?

    Thank you much

  • Hi Rosie! The clamp lock clamps onto the track of the sliding door inside your house to prevent the door from sliding wider. We also have Charley bars as a locking alternative. For the In The Glass option, you would have to select the options based on your glass slider’s specifications to determine the price. We also recommend working with a local glazier to measure your glass and install the unit. Please feel free to email us at for more information on the process!

    Grace Fuh
  • how does the slider lock to stop intruders? does it lock between the existing door the the insert?
    how much is the in glass unit? do you offer installers or is this diy?

    rosie casado
  • Hello! It really depends on the type of alarm system you have. We would love to talk to you on the phone, as it may be easier to explain that way. Essentially, you’ll need to find a way to maintain the integrity of whatever kind of sensor system you have. This may mean installing another or moving one sensor so they align with the new position of the pet door (if that’s the system you have), or another solution would be to semi-permanently install the pet door on the side of the stationary panel.

    Something you may also consider is the Pet Door Guys “In the Glass” unit. With this, you swap out your current pane of glass in your slider, with a new unit that includes a pet door embedded. This can be a great option for homes with alarm systems as it uses the current frame, lock, and configuration of your sliding door (you only change the pane of glass inside the frame).

    We’d love to help more! Please give us a call at 800-826-2871, or email us at if we can help in any way! We love to talk pet doors 🙂

    Kate Miller
  • I have an alarm system so if I put a doggie door in my slider will it upset my alarm system

    Hilda Harp
  • Hi Lisa,

    Panel inserts are a great solution if you want to put your pet door in with your sliding glass door. They can typically be removed extremely easily (especially the Endura Flap Thermo Panel or Ideal “Fast Fit”) and come in a variety of styles to fit your insulation and flap-size needs. When installed correctly with the draft stopper, weather stripping, and correct tension, they seal nicely with your existing sliding glass door and door frame.

    If you have any questions, we are very happy to help talk you through options and details for any pet door. You can shoot us an email at, or give us a call at 800-826-2871 Monday – Friday from 7:30am to 4pm PST.

    Kate Miller
  • We are considering this as an option for our new dogs; wondering if they ever fixed your gap issues?

  • Hi there!

    We’re all about solutions! To better be able to make a recommendation, we’ll need some more specifics. Be on the lookout for an email from PetDoors! Depending on the details, we can find a way to get your door back to its full insulating potential. I look forward to hearing from you!

    Kate Miller
  • Hello!

    I purchased one of your pet doors for our vinyl sliding glass doors, and the installation went relatively smooth. I had to order an extra extension, as my door was a bit taller than the standard sizes. I like the look of it and am close to being very happy. There is one nagging issue. I sprung for the double pane, as insulation is important. However, I didn’t consider that there would be such a significant gap left between the existing sliding glass doors, as now the doors are not fully matched up frame to frame when closed. The tape that was provided (the draft stopper you mentioned above) to close this gap does not form a seal, does not remain stuck (it’s simple tape glue?) when the wind blows, and is in general a lot less insulation than existed before. So we now have a significant air leak coming through the gap left between the two prior existing sliding glass doors when they are in the closed position. Do you have a better solution for this? At this point, I’m regretting not just having a door installed in the wall…

  • Hello!
    I have just the solution for you! For anyone having issues with air passing through their slider, we highly recommend using what we call the “Draft Stopper,” found here: It’s designed to seal the gap created between stationary and sliding glass doors when a panel doggy door is installed.

    The center post weather seal strip (draft stopper) should be installed on the inside of your home. It can install on either the back edge of the sliding door panel or the leading edge of the stationary panel. Then, you can trim it with scissors as needed to fit the desired width and length. Make sure you clean the edge of your patio door with rubbing alcohol before installing to assure a good seal.

    I hope this helps! If you have any more questions, feel free to send us an email at We’re happy to help!

    Kate Miller
  • But what do you do about the air coming through the sliding doors where they no linger meet at the frame edges? I cannot get them sealed no matter what i do.


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