Will Your Patio Pet Door Fit?

Sometimes There's Only One Place to Put the New Pet Door: Next to the Sliding Glass Door. And yet... What if it doesn't fit when it gets there? This is especially worrisome if you're purchasing a custom pet door like the custom Whiskers & Windows Cat Door for Sliding Glass Doors

If you follow these steps, you can be sure that what FedEx drops off is going to fit on the first try.

Step 1 - Measure the Height of Your Sliding Glass Door Track

You'd be surprised how many people skip this step, assuming that what they have must be 'standard size.' It is true that sliding glass door tracks tend to cluster in particular height ranges, like 75" - 77", 77" - 80", and tall 93" - 96". However, there are many different door sizes in the middle, and that's why a few manufacturers like Ideal and Endura Flap make custom sizes to fill in the gaps. Don't take the chance! Getting a properly sized product is imperative to the smooth operation of your new door pet door system.

Measure your track! Here's how: Put the end of your measuring tape up inside the track at the top as high as it will go and measure down a convenient distance and draw a line with a pencil. Then put the end of the tape down into the track at the bottom of the track as deep as it will go and measure up to that line. Add the two together. The result will be very accurate.

Remember that there is no such thing as standard height or a standard door! When measuring your sliding glass patio door, we recommend measuring the specs (door height and door width) in two parts. Then, when you look at the various pet door height adjustment ranges, you may very well find that the measurement you've taken is quite close to the limit specified or even outside that limit. In this case, it never hurts to double-check! Write that number down, so you've got it handy.

measure track sliding glass dog door

Step 2 - Measure Your Pet(s)

The first piece of advice is you don't want to pay too much attention to sizing suggestions such as 'for dogs to 60 lbs' or 'pet doors for German Shepherds.' If you look at all the different breeds even though they weigh a certain amount, their body style may be completely different, and you also have variation within the breeds. For example, you can have a 60-pound English Bulldog or a 60-pound Greyhound. One is short and stocky, and one is very tall and skinny. You have to measure them! And then you have to exercise your judgment about the needs of your pets. You'll find more detailed information at 'Measure Your Pet' so we're not going to repeat that here. Suffice to say that if you skip this step, you'll probably buy a pet door larger or smaller than you really need, especially if you have cats. That's why you can search for specific doors, such as cat flaps for patio doors

When you're done, you should be able to say how wide the flap needs to be, how tall you want the opening above the ground, and how low you'd like the step-over to be.

measure your pet guide to choosing the best size pet door

That said, you've got one more step if you want to be sure. Simulate the opening--it's easy if you have a roll of duct tape and an open doorway--and call the pet through several times. Or for smaller pets, you can make a hole in cardboard and use a treat to coax them through. That's where you'll be able to judge if you're correct with your measurements, and you'll have a chance to apply some corrections if needed. For example, if you're dog thinks he needs to do a little hop going through, you'll want to give him a little lower step over at the bottom. If you see them brushing their sides, then it should be a bit wider. In the end, it's your judgment that matters in a situation that inevitably has a subjective element to it. There just isn't a black and white rule that you can blindly follow, and you know your pets best. We can get you close, but you're going to have to make the final decision.

Step 3 - Check to See if the Framing on your Slider is Vinyl

There are some patio pet doors specifically designed for vinyl-framed sliding glass doors. If that's what you have, then we think you should start with these as they have some decided advantages which we'll discuss in a minute. If you don't have a vinyl slider, skip this step because these pet doors aren't going to work for you. Also, keep in mind that there are some possible reasons for not choosing one of these particular patio pet doors as the flap sizes are limited, and so are the height ranges. Finally, if you aren't sure if you have vinyl, you can take a spoon and tap on the frame. If it makes a "ping" sound, then you have aluminum, but if it makes a dull "thud" sound, then you have vinyl.

Here are the pet doors we think you should consider if you've got vinyl framing. The Endura Flap Vinyl Sliding Glass Dog Door, Endura Flap Vinyl Sliding Glass Cat Door, Ideal VIP, the Ideal VPP and the Ideal VIP Cat Flap. Remember that your solution may be a patio pet door with a metal frame.

So, what are the advantages of choosing one of these vinyl-framed Ideal pet panels for your vinyl-framed slider?

  • They 'look' better -A vinyl-framed patio pet door just naturally seems more appropriate for a vinyl-framed slider. The thickness will be more similar, and the look and feel of the pet door will match more closely.
  • They'll mate to your lock -Ideal has figured out a way to adapt their patio panels to accept the locking mechanism of 'most' vinyl-framed sliding glass doors. You'll need to look at the installation directions we provide for a four-color picture of the specific lock mechanisms they work with to be certain. This is a huge point! Although any pet door you buy will have some way to lock your slider, in no other case will your existing lock work with the pet door!
  • You'll Avoid Some Specific Fitting Problems - In addition to the locking mechanism being taken care of, you won't have to be concerned with whether the rail might be a problem (see below).

Ok. Why Might You Not Choose One of These? 

  • Your measured height isn't in the range - Your height measurement must always fit the adjustment range given, and these doors do have limited adjustment ranges.
  • The flap dimensions offered aren't appropriate for your pet - There are only a few sizes offered here, and this is really important.
  • The installation is too difficult - A handyman shouldn't have any problem. However, these are at the 'hard' end of the range. You can review the installation instructions to judge for yourself to see if it's a DIY or you have to hire out.
  • You want a temporary installation - These Ideal pet doors are not intended to take in and out, and you do have to drill them into the track of your sliding door.
  • They're too expensive - There are more economical patio pet doors than the ones you'll find in this group.
  • The pet door is going to require that you move your security system contacts, and you don't want to do that - See below for a solution to this problem.

If you've checked out the vinyl-framed pet doors and are happy with what you've found, you're done! Skip to Step 5 to think about some specific issues.


Step 4 - Either You Don't Have a Vinyl-Framed Slider or You Aren't Happy with the Vinyl-Framed Pet Door Solutions

No worries. So long as you pay attention to the height measurement that you've already taken to pet door opening dimension requirements that you've already settled on and a couple of potential installation issues that we'll layout below, you're going to find something that will do just fine. Here are the remaining installation issues to think about:

  • See if your home security system is affected - If it is, then usually the solution is to set up a second set of contacts so that the security system works with the pet door in place and also when it's been removed. You'll probably need your alarm company to do this for you. Alternatively, you may be able to move the stationary panel to one side and install the pet door between it and the opposite jamb. 
  • Check your rail - Sliding glass doors roll on two wheels which ride on a rail. Usually this rail is metal, short--around, say, 3/8" tall, and narrow--say 1/8" thick, its about the size of a pencil. Any pet door your purchase will straddle this rail with no problems. Sometimes, however, this rail isn't this common type. If you encounter a 3/4" wide rail that is about 1/2" to 3/4" in height, or any rail markedly different from what we're describing, the pet door won't straddle it and you've got a problem. We'll talk about problems below.
  • Check the locking mechanism of your slider - Some locking devices mount on the inside face of the sliding glass door. These aren't a problem. Others are built into the center of the edge of the slider. The ones mounted in the center of the edge are going to mate to some hardware in the jamb of your sliding glass door. That hardware is going to be in the way of your pet door sliding up tightly against your jamb for a good seal against the weather. You've got three possible solutions.

Option One: You can simply remove the hardware in the jamb. You'll use a Phillips-head screwdriver to do this. Remember, the pet door is going to come with an alternative locking method that doesn't rely on the locking mechanism the sliding glass door uses.

Option Two: You can move the stationary panel and install the pet door between it and the other jamb. In this case, not only will your present locking method continue to work, but you'll also avoid any modifications to your security system. However, you will lose the ability to have a temporary--put it in when you want and take it out when you want--installation.

Option Three: We've had some unusually capable people modify the pet door to fit over the hardware instead of removing it. We're not going to suggest this one. You're on your own if you try.

If the issues noted here all check out then you're in business. Please, however, review Step 5 where we'll bring up some issues to think about that are more general.


Step 5 - A Few More Things to Think About 

  • Should I get single pane or dual pane glass?  The glass in your house--unless it's pretty old or in Florida--is dual pane for a reason. Dual pane glass insulates much better than single pane glass options and, as well, attenuates noise much better. If you're going to live with the pet door for a long time or if you're planning 4 season use, it might be worth it to get dual pane. If you'll be moving soon or if you live in a temperate area, single pane may be just fine.
  • What's LoE'?  LoE' or Low-e glass has a coating inside the insulated glass unit that greatly improves the uv resistance and thermal efficiency of the glass. This is only an option for dual pane glass sliding doors and will not come with any of the single pane versions of the pet doors. Get the benefits of a shade without sacrificing your natural light!
  • What if my slider isn't in a height range offered?  You'll need a 'custom height' patio pet door for unlisted glass door sizes. You can get the Hale patio panels and the Thermo Panel IIIe in just about any height including very short for a sliding window. The Ideal Fast Fit (and the Fast Fit Panel for Cats) may be had with an optional height extension for heights above 80" but these cannot be had in heights shorter than 75".
  • How do I lock my house?   If you're getting a vinyl-framed pet door we've already answered that question. Your pet door is (probably) going to mate to the lock on your sliding glass door. If you're getting a metal framed pet door, then you'll be getting an ancillary lock with it. Generally, these are deadbolt locks that require installation at the top of the sliding glass door or in the bottom track. In both cases the results are probably going to be fine. However, there is a better method. Get a 'Charley Bar'. These are a commercial version of the old 'broomstick in the track' idea, but mount at about waist height. Because they're closer to the center of the slider height, they provide more even pressure against the pet door and will result in a better seal and fixed panel. Patio pet doors do not come standard with a 'Charlie Bar'.

wedgit charley bar to lock sliding glass door with doggy panel sliding glass door dead bolt lock

Wedgit Charley Bar          Dead Bolt Foot Lock

  • Do I want to match my door frame color?  Most of the time we think so. However, there's one circumstance where you might not want to. If you have bronze--very dark brown--framing, the additional pet door framing in bronze will stand out quite a bit. If you purchase a satin frame pet door you'll see it less and you might like it more.
  • What if I have two glass panels and they both slide?  You can use many of our doors for a slider that opens in the center, as the difference would be the installation of the panel.In order for it to remain stable usually they would go into the jamb on the side and into the track on the top and bottom. With your situation what we would suggest is installing the panel by offsetting it to one side so it is not directly in the center, this way you would still have full use of one side of your sliding door. Then securing that sliding door that you moved to put the pet door in with some type of locking device (charly bar, foot lock, dowel in the track...etc) so that it remains stationary supporting the pet door on that side for stability.
  • What if I have four glass panels and the center two slide together?  First check to see if you might move one of the two stationary panels to the side and install between it and its corresponding jamb. If that doesn't work for you then you'll need to install one of the temporary installation type pet doors (a spring-load like the Ideal Fast Fit or the Thermo Panel IIIe) by moving one panel to the side. Then you'll need two dead-bolt type locks to hold each sliding panel against the pet door. Each patio door, whether a two-panel or rare three-panel, can have their pet door insert in different places.
  • I'm moving soon. Is this thing going to travel with me?  If your measured height is in the range 78" - 80" then cross your fingers and spring for the better model as this tends to be pretty much the most popular range. Chances are pretty good that it's going to fit your next house if it has a sliding glass door. Outside that range it's a long shot.
  • What if I've Mis-Measured?  It happens. What is more common, though, is that your measurement is very close to (or even a little below) the bottom of the adjustment range of the pet door you want. In this case you may have a problem even though your measurement is in the adjustment range. This is because the pet door needs to get a little shorter to get up and over the bottom rail to get into the track. If it's already close to it's shortest adjustment range, it may not be able to get short enough to actually be installable. The opposite problem is when your measurement is at or a little above the top of the adjustment range. We recommend a discussion with our customer service department in both these cases. However, we also should mention that about 3/4" can be trimmed off the top of the Thermo Panel 3e to help fix any mismeasurements.

Final Thoughts

We're sorry if this sounds like building a space shuttle, but as far as pet door installs, this one has a TON of variables that need to be checked to get the right product in the right situation. It's the nature of the sliding glass door world that there are some issues to be sure of before you buy, or you may end up having to send it back. We hope we've helped to avoid that problem. If there is anything at all unclear about this text, please call our BBB A+ rated customer service department and let us help you be sure of getting it right on the first try.

Also, if you have some additional issues you'd like to see addressed here or some text you'd like to see change, we'd very much appreciate your comments!! Just email to, and we will get back to you as soon as possible.