The Problem a Plain Flap Doesn't Solve
A manual flap door lets anything through that's small enough to push it open, your dog, the neighbor's cat, a possum, occasionally a raccoon working out the hinge. Electronic and microchip pet doors exist to fix that one problem: selective entry. The door stays locked by default and only opens for animals it recognizes. Everything else about the door, the flap, the frame, the tunnel, is identical to a manual model. The electronics are really just a lock with a sensor attached.
Two Different Ways the Door "Recognizes" Your Dog
There are two distinct technologies sold under the umbrella term "electronic pet door," and they aren't interchangeable, so it's worth knowing which one you're buying.
RFID collar tag / key fob doors. These are the older, simpler electronic doors. Your dog wears a small battery-free RFID tag on the collar, and a sensor in the door frame reads that tag when the dog approaches. It's the same passive-RFID principle as a building access card. Read range is generally reliable and consistent because the tag is designed specifically to be read at that distance and angle, and it doesn't care about coat thickness or how the dog is standing.
Implanted-microchip-reading doors. The more advanced category, often sold specifically as "microchip pet doors", reads your dog's existing ISO 11784/11785 implanted microchip (the 134.2kHz chip your vet or shelter injected between the shoulder blades), the same one that's scanned at vet clinics and shelters. No extra collar hardware is needed; the door reads the chip as the dog's neck/shoulder area passes close to the sensor in the flap. The appeal is obvious, one less thing to buy, lose, or forget to put on. The trade-off is that read reliability depends on how close the chip passes to the sensor, and very deep or migrated chip placement, very thick or matted fur, or a dog that squeezes through at an angle can occasionally cause a missed read that requires a second approach. Manufacturers of these doors typically also let you register a backup RFID collar tag for dogs whose chips read inconsistently, which tells you something about how often that workaround gets used in practice.
Multi-pet households program each authorized pet's chip ID or tag ID into the door's memory, most doors support somewhere between 10 and 40 stored IDs, which covers a household with several dogs and cats with room to spare.
Selective Entry, Not Selective Exit
It's worth understanding what the lock is actually doing. Most electronic pet doors lock the entry direction only by default, your dog can always push out, but only a registered chip or tag unlocks the door to come back in. That's the mechanism that keeps out strays, feral or neighborhood cats, foxes, raccoons, and opportunistic wildlife: the door simply won't unlock for an unregistered animal, no matter how hard it pushes. Most models also offer a curfew or full-lockout mode you set manually or on a timer, which locks the door in both directions overnight, useful if you want the dog confined indoors after a set hour regardless of chip recognition.
Batteries, Not Mains Power
Almost every electronic pet door on the market runs on replaceable batteries (commonly four C-cell batteries) rather than being hardwired, which matters for two honest reasons: batteries need periodic replacement (typically quoted around 12 months of normal use, though households with multiple pets triggering the door constantly will drain them faster), and a dead battery generally leaves the door either fully locked or reverting to a manual push-through flap, depending on the model's fail-safe design, check this before you buy if a locked-out dog would be a problem for you. Good doors give a low-battery warning (an audible beep or blinking light) well before the batteries actually die.
Weatherproofing Is a Real Trade-off, Not Marketing
Because an electronic door is normally closed and locked except for the moment a registered pet passes through, it typically seals better against drafts than a basic manual flap that swings freely, the flap sits in a locked, closed position most of the time rather than resting loosely in the frame. Better models add a brush seal or magnetic closure strip around the flap edge to cut down further on drafts and rain intrusion. That said, no pet-door flap seals as tightly as a solid wall, and the frame/sensor housing does add a small amount of bulk and a few more points where cold air or moisture can find a gap compared to the simplest flap-only designs, something to weigh honestly against the security benefit rather than assume away.
What Electronic Entry Doesn't Do
It's worth being clear-eyed about the limits. Chip- or tag-based locking stops other animals from entering, it is not a home-security device. The lock mechanism is built to resist paws and noses, not crowbars, and a door with a large enough flap opening can still be reached through by a person or squeezed through by a determined larger animal. Treat it as pet management, not perimeter security.
