10 Best Cat Doors for Windows of 2021 – Reviews & Buyer Guides

Cat lovers are often as finicky as our pets. It’s why we love them so much. But if yours is an indoor-outdoor cat, their favorite foible is probably their most annoying trait. Cats want to go out, and five seconds later they want to come back in. And vice versa. It’s maddening.

But if you install a window cat door, kitty can come and go at will, and you can even watch them through the glass! Kitty can enjoy freedom and you can still keep an eye on each other. So let’s find the best cat door for your window…

• It recognizes your cat’s microchip so other cats are locked out.
• The cat flap has a 3-year warranty.
• The car door is battery powered with a battery life of up to a year.

The Best window cat door on the Market 2021

1. Depets Large Window Cat Door

In some ways, a cat door is convenient because your cat can set their own schedule. But a ‘furrent’ you may still want to control access to some extent. You may want your cat indoors during the night. Or you may want to block outside access if you have ferals or wild rodents.

Depets has a four-way lock that allows you to do this with ease. You can set it for entrance-only, exit-only, both open, or both shut. That way, if its rainy, muddy, or snowy, you can keep unwanted guests out. This is a window cat flap, so you can see whether the cat approaching is yours or the neighbors, then you can flip the switch to let the cat in or lock him out.

The inlet width is about 7 inches, but you need a 9-inch window space to mount it. Your cat needs to be 23 inches at its widest point and under 20 pounds to comfortably use this door. The door has a brush strip so it opens and closes quietly when the cat passes through. Its outdoor-facing surface is made of waterproof, weatherproof ABS plastic. It’s quite easy to install.

This cat door for windows is convenient and intuitive. It has color-coded four-way locking options and all the mounting screws are included in the shipping package.

Pros:

• It can accommodate both cats and dogs.
• The flap can be installed in a window or a wall.
• The cat door has 4 lock-unlock options.

Con:

• The package comes with detailed instructions, but they’re a little hard to follow, so you may need to find some demo videos or call an experienced user to help you mount it.

2. Ownpets Screen Window Cat Door

When you buy a pet door from Ownpets, you’ll see that it’s designed for cats and puppies. This is a sizing issue since the outer dimensions are 11.4 inches by 9.4 inches. The inner dimensions – the section your cat needs to squeeze through – are 10.2 inches by 8 inches.

The cat flap is built for bug screens, so don’t install it on a wooden door or glass window. When the cat or dog passes through, the magnetic clip automatically opens or closes accordingly. The paw print motif on the cat door is a nice aesthetic touch. It brands yours as a cat-loving home. The mesh paneling also helps your cat door blend into the screen door more effectively.

This cat door is simple and intuitive, and its magnetic clips give your cat full access. But it also has two manual clips so you can lock the flap when you want to limit your pet’s entry or exit. This can be helpful during bad weather, at night, or when you’re expecting a visit from the vet and you don’t want kitty to go AWOL. The clips are blue for easy spotting on the gray mesh.

Ownpets manufactures cat doors for screen doors and window mesh. The flap is magnetic but it has manual override clips you can use when you need them. The clips easily slide open or shut.

Pros:

• The flap is designed for screen doors and mesh windows.
• It has a magnetic flap for easy opening and closing.
• All the mounting hardware is included.

Con:

• You can mount these on your windows, but only on the bug mesh, not on the glass.

3. PetSafe Freedom Window Cat Door

We call them French doors, but they’re also known as French windows. And PetSafe Freedom Doors are customized for this type of entryway. The cat doors come in five different sizes to match your window dimensions. This cat door fits into sliding windows, so you don’t have to cut or drill through the frames or the glass. You simply fit it at the edge of the horizontal slider.

The cat doors are the same length as your glass door/window opening, so you don’t need tools or experts to install it. Slip into the slider and secure it in place. The upper part of the cat flap is solid while the flap section is flexible. It does have a lock though, you can shut it at night or at other times when you’d prefer your cat to stay indoors. Locking keeps the ferals outside too.

Most cat doors for windows are made of plastic, but this one is made of tempered safety glass to match the glass it’s installed onto. The flap is magnetic so your cat can easily trigger it. The solid section is made of outdoor-grade aluminum so it can withstand harsh weather, wind, and rain.

Anyone can install the PetSafe Patio cat flap because it doesn’t need any special skills or tools. And because it slides in or out of your French windows, it’s a good choice for temporary tenants.

Pros:

• You can install it without cutting or drilling.
• The cat door comes in five different sizes so you’re sure to find the right fit.
• The flap section is tinted to help with temperature control.

Con:

• The whole device weighs 16.26 pounds, so while you don’t need special skills to mount it, you might still need help because it’s weighty and bulky.

4. SureFlap Microchip Window Cat Flap ( Our Top Pick )

The best way to protect your cat flap is to ‘teach’ it to recognize your cat. That way, strays, neighbors’ pets, and wild rodents can’t force their way into your home. SureFlap is designed to work with RFID. So it can detect your cat’s microchip and automatically open when your cat approaches. The chip-reader can be preset to allow up to 32 distinct pets through the flap.

This means if you have more than one cat, you can program your door to read all their individual chips. And if your cat isn’t chipped, you can still buy a collar with an ID tag that your door can read. These are sold separately though, so leave room in your budget for it. But for all its fancy tech, the SuperFlap is on the smaller side at roughly 4 inches by 5 inches.

SureFlap is a self-contained low-maintenance cat door. So once you mount it and load its batteries, you’ll probably forget about it. Especially since the batteries last a whole year. When they’re ready for replacement, the cat flap will flash red to remind you. The door uses 4 batteries. They’re AA alkaline non-rechargeables so buy a set when you order the flap.

This cat door is versatile and easy to use. But its opening is on the smaller side, so you should only buy it if your cat is on the smaller side. For a Maine Coon, you may need something bigger.

Pros:

• It recognizes your cat’s microchip so other cats are locked out.
• The cat flap has a 3-year warranty.
• The car door is battery powered with a battery life of up to a year.

Con:

• While the flap can read up to 32 distinct cat microchips, you have to buy a compatible collar if your cat isn’t already chipped. The flap can read the collar’s ID.

5. Success Window Pet Door

Have you tried taking a waist measurement of your cat? It’s about as much fun as deworming. But it’s important to know how ‘wide’ your cat is because if you get a cat flap that’s too narrow your cat won’t use it. Success Pet Doors fit cats with a maximum circumference of 23.62 inches.

Of course, your cat can tell whether or not s/he’ll for just by wiggling whiskers because their whiskers are roughly the width of their bodies. Sizing aside, this cat door easily mounts onto your window. It has screws included for door mounts and double-sided tape for window mounts. You’ll need the tape because you may need plywood backing for window installations.

The cat flap has both magnetic clips and manual clips, so you have four settings to control entry and exit. The car door is also shielded against rain damage and strong wind. It has brushes along the door edges. These brushes reduce noise levels by lowering friction as your cat passes.

Success pet doors are versatile and easy to install. But be careful about dimensions. The outer and inner measurements mean your ‘extra-large’ cat flap may not be as big as you think.

Pros:

• It comes in four sizes to suit your cat’s size and breed.
• The outer margin is about 9 inches and the inner measurements are roughly 7 inches.
• The door has 4-way locks so you can control cat access at will.

Con:

• This cat door is marketed as suitable for windows, but you need to reinforce the base with plywood or plexiglass before you can mount, so you may need a skilled technician’s help.

6. Ideal Pet Sash Window Door

Mounting a cat flap sounds like a lot of work. Especially if you’re installing it on a window. It seems like it would involve glass-cutting devices like the ones spies use in movies. But with Ideal Pet, you don’t need any lasers or crosshairs. The cat flap is designed to slip into the tracks of a vertical sliding window with no tools required. And you can stretch or shrink it to fit your frame.

The Sash window has a flap in the middle and aluminum sashes on the sides. Each sash has a knob above and below it. Use the knobs to stretch or shrink your cat flap by up to five inches. This only helps the framework sit snug, but it doesn’t influence the size of the cat opening. This opening is 7.5 inches by 10.5 inches if you buy the large size, but there are other sizing options.

The aluminum sash has a clean white finish that blends into your window trim. The flap is flexible, see-through, and non-toxic, so your cat will love it. It has a manual lock as well.

Pros:

• The cat door can adjust for 27-inch to 32-inch windows.
• The flap is suitable for vertical sliding windows.
• Every cat door in this series has a limited lifetime warranty.

Con

• This cat flap is great for sliding windows, but you can only install it under vertical sliders, not horizontal ones.

7. Ycozy Four-way Window Cat Door

In the cat-loving world, there’s often a raging debate about outdoor access. Some owners believe letting a cat go outside is risking one of the feline’s nine lives. Others think locking a cat indoors is cruelty. If you believe in outdoor access, you have an additional worry, because your cat can get out … but other cats can come in too. The four-way lock on Ycozy helps you prevent that.

Once your cat is back inside, you can set the door to open outwards only, meaning your cat can go back out, but others can’t come in. You can also set the lock to allow in-out movement or to lock completely. Beyond that, you can order Ycozy is a subtle white, an earthy brown, or a dark black, depending on the effect you want. It has magnetic locks in addition to the manual ones.

This cat door is intended for smaller cats though. It allows a maximum weight of 11 pounds and its flap is barely 6 inches by 6 inches. It does have a damper brush for noise control though.

Pros:

• It comes in three colors to match your window décor.
• The door has four-way locks for convenient cat control.
• The package includes multiple screw sizes to suit your window width.

Con:

• The door flap sometimes sticks in snowy weather, so you may need to oil it.

8. Perfect Pet Soft Flap Cat Door

Some cat lovers like magnets and fancy features. Others are content to just have a see-through flap. The latter will love Perfect Pet. It’s fitted with a soft flap in two sizes, so get the right fit for your cat. Because the flap is clear, your cat can peek to see if s/he really wants to go inside or outside. Unfortunately, raccoons, strays, and other critters can peek inside just as easily.

Perfect Pet has a telescoping frame, which means it can be adapted to different door thicknesses. It also means you can easily install it on a window, though you do have to reinforce the glass with plywood or plexiglass to ensure a snug fit. The cat door takes about half an hour to install on a door but may take longer for glass windows because of the extra window padding.

This flexible cat door uses thermoplastic for the flap. It’s mounted on the inside of the door or window, so nobody can sabotage it from outside, not even the cutest cat burglar, pun intended.

Pros:

• The flap is see-through so your cat knows where they’re going.
• The frame can be adjusted by about 2 inches.
• The installation process is relatively pain-free.

Con:

• The flap isn’t magnetic so it won’t slip shut behind your cat.

9. Luya Pet Screen Door with Magnetic Flap

Suburban living isn’t as safe as it used to be. So while you’d rather leave the door open and let your cat walk in and out at will, it could become a security issue. There’s a compromise though. On hot, balmy days, you can open the solid door or window and just leave the bug screen shut. How does this help your cat? Install a screen door cat flap. It’s pretty easy to do.

You’ll have to take down the screen, cut a hole through it, and screw the flap into place. But the process is far easier than it sounds. And this screen cat flap has a magnetic lock that shuts itself once the cat has passed. The magnet isn’t pet-specific though – any animal can push it open. That’s why the door has two extra clips you can manually push to lock the cat door.

This is a pretty screen door, and the paw print is an especially nice touch. It can be a security risk to you though, so unless you’re inside a safety fence, take extra with human intruders.

Pros:

• It mounts easily on your screen door or bug mesh.
• It’s suitable for large cats and small dogs.
• The flaps have both manual and magnetic clips.

Con:

• Keep an eye on the screen, because determined human intruders can easily cut through it and find the way into your home if the main door/window is open.

10. Patio Pacific Sliding Window Cat Door

French doors and sliding windows are a clever, stylish way to let more light into your home. But you may worry about people (and pets) walking into the glass. So why not install a sliding pet door for your cats? It doesn’t need fancy tools. Just open the door to fit the width of the cat flap and clip it in place. Patio Pacific is designed to work with horizontally sliding glass.

The window has to be safety glass that at least 1 inch thick. But lengthwise, your cat door can be adjusted two or three inches for a better fit. This model suits glass door dimensions of 34 to 37 or 46 to 49 inches. The frame is aluminum so it can withstand rain and sunshine. It fits by spring-loading so its latch is secure on your slider track. The flap is made of flexible vinyl.

Pros:

• The cat door attaches using spring-loads and thumbscrews so it’s securely latched.
• The flap is see-through, just like the glass door, so your cat has a good view.
• It slips neatly into place without using tools or complicated steps.

Con:

• The flap cover is a little tricky to remove. Watch a few demo videos to avid breaking it as you try to yank it open for the first time.

Buying Guide

The most important consideration when you’re trying to find the best cat door for your window is suitability. Make sure it’s designed to fit in a window, not a door. Otherwise, you’ll waste money, damage your glass, and possibly injure your cat (or yourself!). What other factors should you consider when you’re shopping for cat doors? Let’s find out together.

Installation Process

Cat flaps for doors are easier to install. You may need a screw gun or some fixtures, but it’s not complicated. For windows, look for the simplest option you can find. Some cat doors require you to cut a hole on the mounting surface, especially for doors. It’s way more complex to cut holes in a window. And if you need to hire a glazier, that’s more cost. So buy one you can mount yourself.

Size of the Cat

You may have heard of ‘chonks’ and ‘chumbus’. These are nicknames that cat lovers use to describe chubby kitties. And lots of us love out kitties fluffy and cuddly, as long as it doesn’t hurt their health. So if your cat is a good feeder, or if you have a naturally large cat like a Maine Coon or Ragdoll, get a window cat door that can accommodate their weight and width.

Age of the Cat

Kittens are way more playful than their elder siblings. And because they’re still small and aren’t as self-restrained, they can be more destructive. On the other hand, older cars may have mobility issues, or might just not be bothered to struggle through a cat flap. So pick a brand that suits your cat’s age and activity level. This includes the mounting height if your window cat flap.

Accessibility for Felines

In the wild, cats are good at squeezing into tiny spots when they need to hunt. At home, they find sneaky hiding places and sneak into forbidden zones like drawers and safes. When we bring this thought process to cat flaps, we realize strays and neighbor cats can easily figure out your cat door. So consider a door with ID tags or magnetic clips that only your cat’s collar can unlock.

Weight of the Cat Door

Your cat’s measurements and dimensions affect his or her ability to get through the cat flap. But the flap itself can be heavy or light. Heavier cat doors need sturdy, solid surfaces, and might shatter your window as the cat slips through. So even if the packaging indicates it’s suitable for windows, double-check whether it needs a plywood base, which would add to the flap’s weight.

Aesthetic Factors

Window-mounted cat doors are highly visible, both from the inside and the outside. The cat might not care, but if you have to look at that ugly thing every time your cat goes out or comes home, it will drive you mad. Prioritize functionality, but think about the visual appeal as well. It’s best to buy a subtle model that blends into your window trim and matches your décor.

Kitty References

Some cats travel with their owners while others are too skittish to do anything but essential vet visits. Also, many cats have specific tastes and preferences. So if your cat can stand it, take them shopping with you. Let the cat test the window flaps at the store, your friends’ houses, or even at the vet. That way, you can buy a brand, style, or size that similar to what your kitty likes.

Interspecies Mixing

You might be a cat person, a dog person, or a ‘bi-pet’ who prefers both. So if your home has both cats and dogs, you want a versatile pet door that accommodates all your animals. Dogs are less likely to use a window entrance. But since your pets are siblings, they watch each other.

And they learn communal tricks, meaning your dog is likely to follow your cat through the window. So get a flap that won’t leave the doggie stuck in the middle. And mount it in a spot where the dog won’t do much damage. Dogs aren’t as graceful as cats so they’ll make more mess!

Let the cat out (or in)!

After thorough research, we can confidently recommend SureFlap window cat door. Here’s why:

• It reads pet microchips so it will keep strays and pests out.
• You can use it in a multi-pet household with up to 32 distinct pet ID tags.
• It’s battery-powered so it works even during a power outage.
• If your pets aren’t chipped, you can buy a compatible collar.
• The battery lasts a year and the flap has a three-year guarantee.
• It’s suitable for windows, but you can also mount it on doors or walls.

Do you have a cat flap or your door or window? Show us in the comments!