10 Myths about Pet Doors: Exposed

Are doggie doors a good idea for your home? Of course they are! Pet Doors are a great way to have a happy and healthy pup. When looking at what to buy, the first step is separating pet door facts from fiction. Read about 10 common misconceptions and some extra pet door facts!

#1 Myth: All Flaps are Made Equal

doggy door replacement flaps - what size dog door do I need?

Not true! Pet doors are conceptually similar, but different pet doors are designed for specific purposes. Factors that determine how a flap is made include climate, electronic preferences, and economical choice.

Weatherproof flaps tend to be slightly heavier than the average flap, with additional magnets to keep things insulated. With electronic pet doors, flaps are made of acrylic plastic. These flaps are sized mostly for small dogs and cats. Automatic pet doors that open, upon reading a collar key signal, have flaps made of plexiglass for larger pets. When looking through our Largest Selection of Pet Doors, be sure to prioritize your needs along with those of your pet so you both are happy with the material and design.

#2 Myth: Breeds Have a Standard Size

Not true! Measuring your pet is necessary for any and all breeds. Although your pet may seem average for their breed, you should still bring out the tape measure!

It is important to make sure your furry friend will fit through their door since they will be using it every day. It is recommended to measure your pet from floor to shoulder, and have the top of the pet door flap installed at least one inch above their back to ensure a comfortable pass. If too small, they'll scrub their back on the door frame every time!

With this in mind, check the flap width too, so your pet does not get stuck. A good homemade trick is to cut a hole in cardboard to act as a guide. An additional item to consider is the step over. This is the space between the ground and the bottom of your pet door. The step over needs to be taken into account when you are choosing a flap size. For more visual information, check out this Measure Your Pet guide with a video included.

#3 Myth: Pet Doors are Made Only for Doors

Dog using Endura thermo in glass pet door - patio door with pet door built in Not true! As every pet is different, so is every home. Doors for pets are now made to be installed in a variety of places within the house. Besides doors and walls, dog and cat doors can be installed in windows, screen doors, the cabinet where the litter box hides, storm doors, and even closets! As there are many hang out spots in the house, there are just as many doors to fit your pup’s lifestyle. One of the more popular alternatives is the sliding glass dog door, which is wonderful options if you are renting your home and you can't actually cut any holes anywhere! Most are called 'pet door patio panels' or 'sliding glass pet door inserts,' and you can even replace a full slider for a sliding glass door with dog door built in!

Pro Tip: How to Install a Doggie Door in a Wall

Many pet owners will choose to cut a hole in a wall and use wall entry dog doors rather than cut into an exterior door. Wall mounts are great because you can remove the pet door and patch up the wall like it was never there! Under window sills, in the kitchen, or even from a bedroom! Garage dog door installations are also on the rise and give you the opportunity to let the cat or dog into the garage for shelter, but not all the way into the house. Installing a pet door can be a fun DIY project!

#4 Myth: Adults Crawl through Pet Doors to get Inside

Plausible...  If you worry about security, even having a back door with a small dog door can be a tough decision to make. While electronic doors can act as a solution for this potential issue, wearing a collar key might not be an ideal situation for you or your pet. Extra-large pet doors worry people even more, though they might meet your big, protective dog on their way in! Intruders would likely fear a home with a large dog door. If you are worried about break-ins while you and your dog are away, you can also invest in an additional security cover for your pet door. This can cover up your dog or cat door from a person from intruding.  The Watchdog covers can give you a pretty burglar-proof doggie door.

While pet doors halt the average adult from entering the house, there have been instances where children forget their house key and are able to crawl through. On the other hand, electronic doors like the High Tech Pet Power Pet are also a great way to keep babies or small children from getting stuck or going outside. A pet door can be secured from unwanted individuals, but can also serve as an emergency entryway.  So are pet doors safe? Well, generally yes, but it’s up to you to use good judgment and take precautions if necessary.


#5 Myth: My Locking Cover Can be Opened From the Outside

Not true!  To ease the stressful thought that animals come through your door/wall or burglars that break into the home, all pet doors have locking covers that can act as burglar barriers. A dog door security cover should be placed inside the home where there is controlled access. Locking covers are made specifically for their door, so there are a few different types out there. However, most are made of steel or a very hard plastic. These security covers do not have tabs or small openings for anyone or anything to pry open from the outside. Many covers also have latches or pin locks to prevent them from being pushed outward.

Often times, the aluminum frames of most doors provide security themselves. It would take a while to break through a pet door! If there is a concern with your existing locking cover, check out the WatchDog Steel Security Pet Door Cover to ensure maximum security.

#6 Myth: Pet Doors Gives My Pet a Headache

Dog looking through wall mount dog door - dog doors for walls Not true! The only reason that a pet door might be hurting the pet is if it's the wrong size! For the perfect pet door size, we measure from a pet’s feet to shoulder; this is because cats and dogs tend to stoop their heads when they go through a pet door. It might seem like this would cause a headache since our pets go in head first.

Dog door flaps are also typically made of a flexible vinyl flap that smoothly passes over a dog’s body. Cat flaps on the other hand tend to be a clear, light acrylic that moves almost as sleekly as your cat. But cats also tend to open the door slower than dogs. Thanks to light and flexible flap materials, our four legged friends don’t mind them!

Pro Tip: When your dog is getting trained to their doggie door for the first time, they are more likely to use the door when they see you poke your head through it first!

#7 Myth: Flaps are Interchangeable if they are the Same Size

NOT true! Sometimes the frame sizes of a pet door are comparable, but the flap? Not so much. Since there are so many flaps on the market, there are only a few that are close in size. Even then, this does not mean any replacement flap can be installed in any door. Pet door flaps are not interchangeable; this is true for any brand. Please see replacement flap size product information for further info.

Cutting flaps to fit is not an ideal situation either, while it may be possible. Fitting a flap in an unfamiliar frame can prove to be difficult. Adding to the installation challenge, a flap on the wrong frame may not seal properly since a door’s magnets can be located in a different spot, leading to poor insulation.

#8 Myth: A Pet Door Can be Installed in Any Door

Almost... There are pet doors made for doors and there are some made for walls. While a pet door can be made for doors, it does not mean any and all doors are fit to use. In order to be installed, pet doors require certain parameters.

An important requirement for installing a dog door is to check are door thickness; and you always want to ensure the material is strong enough to support the pet door. Pet doors that are not self-framing would require additional steps during the dog door installation if you are installing a doggie door through hollow-core doors. Be sure to check the specs of any pet door you are looking into to make sure it is a proper fit for your home. You'll also want to consider the shape and look of your door. Lots of them have door panels that accent the door, so you'll want to support the pet door with caulk or shims for stability when they go over these reliefs. Check out our blog post on Installing a Cat Door into a Hollow Core Door!

#9 Myth: My Dog Won’t be Able to Push the Door

Installing a dog door for a Schnauzer mix mutt waiting with his pure bred schnauzer to come in the Ideal Original back door for doggie doorSometimes! This is a common concern with smaller pets and goes hand in hand with training. A new pet door can be confusing for your dog, but it does not mean they will never get it. Small pets may feel like their new door is overwhelming and have trouble going through. It is a good idea to try and purchase a smaller flap relative to your pet’s size. The bigger the pet door, the heavier the flap. If you have big and small pets sharing, try looking for flaps with adjustable magnetic strength. Reducing or adjusting your magnets can make the flap light enough for your small pet, so they can play outside too! There are also motorized pet doors, which do not require your pets to push anything.

For first time pet door users, getting used to the flap’s touch is key. We recommend opening the pet door from the outside with a treat to get familiar with the door’s ability. Another trick to use is to slowly have the flap trail across your pet’s body so they can get comfortable with its touch. Every pet’s comfort level is different. Practice makes perfect, so be patient with your pet and soon they will gain their confidence!

#10 Myth: A Pet Door Will Raise Energy Bills

Not true! With a pet’s newfound freedom, they might be running in and out the house more often than not. Having a pet door can allow the outside air to come in the house, and if you are in extreme weather, this is not good news. But it doesn't have to be this way! In order to cut down on your energy bills be sure to look for energy-efficient pet doors with strong magnetic strength. Magnets on the bottom and sides ensure a quick and tight seal. For the best insulation, we recommend the Endura Flap.

Electronic kitty and dog doors are a good option as they generally create a tighter seal against the weather than a traditional dog door flap when not in use. It helps lower both your heating and air conditioning bills. If you have a patio panel, you can increase the insulation using weather stripping. You won’t worry about the flap swinging open when your pet goes outside. You won’t have to pay extra for your pets’ playtime!  And remember that the size of the pet door opening and closing is smaller than your entire “people door” opening and closing each time your dog wants out! For our recommendations, check out The Best Dog Doors for Cold Weather!

Bonus: 10 Fun Facts About Doggie Doors 

Dog doors simplify life for man’s best friend. They don’t require your assistance to go out, so there is less barking and scratching at inconvenient times of the day or night.

There is much more to doggie doors than the traditional plastic flap in the back door. These ten facts about dog doors offer surprising revelations on this staple of pet ownership:

  1. Famous scientist Sir Isaac Newton is credited as the inventor of the first pet door. It was actually designed with his cat in mind. Newton referred to his creation as a “cat flap.”
  2. An electronic dog door opens or unlocks when it detects a magnetic sensor in your dog’s collar. This feature restricts all other stray animals from entering your house. There are also microchip pet door versions, where the flap will unlock for programmed chips.
  3. Glass dog doors can be installed in sliding patio doors. Different types include single pane glass panel, dual pane glass panel, and the special purpose panels.
  4. Direct sunlight can cause plastic dog doors to warp and fade over time. For that reason, it is best to install the plastic flap on a side of the house shaded from the sun.
  5. Most patio dog doors feature a simple pin lock that you can use to connect your sliding patio door to the pet door.
  6. Rounded edges help your dog fit through pet doors easier. Square edges can lead to some bigger dogs getting stuck on the corners.
  7. What you thought you knew might not be true…comment below if you have other facts about pet doors or would like to learn more.

Frequently Asked Questions

Are dog doors unsafe?

No, dog doors are perfectly safe for dogs so long as you have checked that your backyard is fenced off and free of any toxic plants or materials that your dog could get into.

Can someone break in through a doggie door?

Are dog doors safe for your home? Most dog doors are not large enough for a person to fit through. For those that are, using the provided locking cover at night and when you are away blocks access to the pet door.


What you thought you knew might not be true…comment below if you have other facts about pet doors or would like to learn more.

At Pet Doors we can help you find the ideal pet products to make your pet happier. Purchase a pet door that fits your home and pet perfectly!

Cynthia Herrera

Written by

Cynthia Herrera

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 Judy,

    It sounds like we might need a few more details in order to assist you. You can contact us at so our customer service representatives can help you out!

    Grace (Staff)
  • i have a storm dog and really would rather place a wall doggie door on inside walll… issue is that my only option is to place it inches from a heating floor regester… this a bad idea?

    judy j komarinski
  • Hi Tina,

    Unfortunately, the installation process would be pretty difficult to do this. If you’ll consider just installing a pet door in the storm door, you should be able to install any of the pet doors found on this page into your storm door. The selection also includes storm doors with pet doors pre-installed.

    For more information on storm doors, you can take a look at our blog post “Should I Buy a Storm Door Pet Door?”

    Please feel free to contact us at for any additional questions!

    Grace (Staff)
  • Can I put a dog door on both the main door and storm door. Like 2 human doors together with 2 pet doors?

  • I loved this article as it provides me lots of information regarding the 10 myths pet doors exposed. You will get the best review over here. It plays a vital role in taking us through. It can be really great for people like me who are looking for grabbing more knowledge about it.

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  • Hi Larcey!

    Thanks for the question! A solution I can think of would be to install a Sure Petcare pet door into the wall or door of the room with the cat food. Sure Petcare carries pet doors that are programmable to work with specific pet microchips and/or an RFID collar key (so you can decide which cat to allow access to the door). Unfortunately, it’s impossible to completely guarantee that one of your other cats is not going to squeeze through with Essie, but Sure Petcare door would most likely be your best bet. There are a number of installation options for their products you can find here!

    Please feel free to email us at or give us a call at 1-800-826-2871 and one of our customer service representatives would be happy to help you out.

    Grace Fuh
  • My Mom and I have found a place together. She’s got a rescue cat that was declawed and has been with her (alone) for many years, Essie (F)-6 yrs old.
    I have three cats (pets of my grown children) that have grown up together: O’Malley (M)-5 yrs, Theta (F) -4 yrs, Iota(F)-2 yrs. My three are fairly playful and get along pretty well.
    With the move has come some challenges with cats. Feeding cats and my cats chasing Essie being two in particular.
    We’ve looked at the automatic/collar charm activated feeder for Essie who is a grazer and needs food access all of the time but she’s so afraid of the feeder machine. Then we thought perhaps using a collar activated door to my moms bedroom so Essie can get to her food at any time and also have a place of peace away from the other three crazy cats.
    I’m wondering if there’s a door that would close fast enough to prevent a following cat from entering through the open cat door on the heals of poor Essie. Do you have any other suggestions? 🙂

  • Hi Andrea,

    Depending on the thickness of the wall you’d like to install in, you could potentially install a wall mount pet door in the steel building wall. Please take a look at the available options we have for in wall pet doors here. For each pet door, the thickness range of the wall that it can be installed in should be listed in the details. Please don’t hesitate to contact us at or give us a call at 1-800-826-2871 with any additional questions – our customer service reps would be happy to help you out!

    Grace Fuh
  • Can a pet door be installed in the side of a prefab steel building or does it need to be in a door? I’m not referring to a metal door, but the metal building itself. I can’t find any information on this!

  • Hi there!

    It would be very challenging for a snake to use a dog door, as they’d have to physically push open the flap. If there are a lot of snakes in your area that you’re concerned about, we recommend getting either a “manual flap” pet door with a tighter seal or finding an electronic doggie door that works for you. Endura Flap pet doors would be the best option for a manual flap, as they have a very tight seal that makes them the most insulating pet door available. It would be practically impossible for a snake to use!

    Hope this helps!

    Kate Miller
  • Do snakes really come in dog doors?

    April Bundrick
  • My family had always been hesitant to get a doggy door, for a lot of the reasons on this list of “myths.” Once we did some more research though, information like this really helped. We absolutely love our Endura Flap, and are so happy we installed a doggy door!

  • I have a hi tech pet door, it slides up and down. No flaps to worry about. My pets wear a collar that uses an RF signal to trigger the door to open. You can push a button that allows them to go out and not in and vise versa. It can be wall or door mounted. Battery or outlet run. We love it. Don’t want a pet out don’t give them a collar the door won’t open for them. You would still have to worry about them sneaking out behind the other. My Bassett hound likes to sit when the heat and ac is on with the door open looking out and barking.

    C Me
  • I’ve had dog doors for years both in the wall and in the door. I prefer in the wall. My 15 year old 5 lb Yorkie can still go in and out but it’s harder For her. Possibly mice get in but mice can get in anywhere. The vinyl doors shrink with time but they last a lot of years. My big dogs, Dobie and Sharpi Boxer go in and out the med. Door very comfortably. Wouldn’t live without them.

  • When searching for pet doors to cater to specific things like weather conditions, electronic vs. manual, etc., there are “Helpful Filters” on the left-hand side of the category pages on that help narrow the search!

  • Hello Bernice,
    Thanks for the feedback!
    We are glad to hear that the patio pet door has been useful! We are continuously looking to improve our products to best fit your needs, so we are always grateful for input and do take it into consideration. Please do feel free to contact us at for any additional comments or questions.

    Edgar Gonzalez
  • I purchased a patio pet door last summer and I couldn’t be more pleased. I am 80 years old and I installed it myself for my English cream retriever. My pup was one year old at the time and growing fast, so I bought a large door. He had been trained to ring a bell when he wanted to go out and that little bell was ringing constantly. The pet door was a life saver. Couple problems: it is not a tight fit and I had to caulk around the edges; the strip that was provided to be inserted between the patio doors, because now with the dog door in place, the gap between the sliding doors is about 2 1/2 to 3 inches, was not wide enough. I shopped many stores and could not find a wider strip. The security panel is thin plastic and is very cold. I taped insulation to the outside of it and that helped a little. My dog has free run in good weather but the door has to be locked in rainy and snowy weather. All in all the door is very convenient in good weather but not so in bad weather. I had to tape plastic on my patio doors as they, with dog door installed became very drafty. I can see where this door can be improved in many ways, but who’s going to listen to an 80 year old woman

    Bernice Day
  • Yes, with every pet door there is a possibility of unwanted critters coming into your home if the pet door is left open. However, most pet doors have some sort of locking cover which can be added to the door to ensure you can lock it and keep them out. Alternatively, some smaller doors are collar key activated, meaning that only the pets with the included collar key can go through the door.

    Edgar Gonzalez
  • We have a lot of cats and possums in the neighborhood would it be possible for them to get in if the dog doesn’t scare them off?

  • Hello,

    There are two brands of pet doors that allow for variable magnet strength: Endura Flap and Hale. Here are the instructions to change the magnets for Endura flap ( and Hale ( If you have either of these brands you should be able to remove or adjust the magnets to make it easier for your cats to push through. Can you send pictures of your door to and a short description of your problem. We should be able to figure something out.

    Ryan Bruch
  • I have 3 cats and a small dog. They all use a small pet door. My husband and I decided to get a larger dog breed so he replaced the small pet door with the large. My cats are not going through it. Is it possible that it’s too heavy for them to push through? Do they just have to get used to It? It’s a heavier storm flap. What can I do?

  • Hi Kim! Thanks for commenting with your concerns! With regard to your first two questions: other than getting an electronic pet door, getting a pet door with a heavy flap, like the Endura Flap, would likely keep smaller animals (squirrels or cats you don’t want using it) from using it, especially without any training. For your last question, you could put rugs, mats, or towels around the inside entrance to your pet door to help reduce the mess. In extra nasty weather, you could also put in the locking cover and go back to limiting their outside times during bad weather. Let us know if you have any other questions!

    Paula Ledgerwood
  • I have three concerns about having a pet door; can someone share their experience(s)?
    1: Do other critters (squirrels, others’ cats, etc.) come into your house through the dog door? My back yard is fenced but my neighbor’s cats come into my yard at their leisure, and we have squirrels all over the place.
    2: I have two cats that do not go outside; how would I keep them from using the door (besides getting the electronic version)?
    3: Allowing your dog to have the freedom to go in and out during nasty weather (snow and rain) leads to muddy paws all over your floors and carpets, yes? Blech.


  • Thank you for your comment! That is something we always try to remind people when ordering, as a lot of people don’t think that far into the future.

    Rachel Long
  • One thing to consider about the size of the pet door is the ability of aging pets to use them. I had always used the Extra Large size for my Collies, and found when buying my current Plexidor that the size recommended for them was smaller. But when one of my older dogs developed severe arthritis in his rear end and had difficulty moving around, I was very happy I’d stuck with the Extra Large – he was able to walk through the door without scrunching down, and I built up the landing outside so he could walk straight through. (The dogs have a room in my finished garage, with the dog door leading to a fenced yard.) Not sure how he would have managed during the day while I was at work if I hadn’t had the larger door. He would have been forced to either “hold it”, or mess inside, both of which would have distressed him.

    Donna Walle

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