Dog door

A dog exiting a dog door.

A dog door is a hinged or spring operated door rather than the more commonly known 'flap' set into a door, wall or window to allow dogs to enter and exit a house on their own without needing a person to open the door. Flaps are hung from the top of the opening and do exactly that - flap. Dog doors generally must be bigger than cat flaps and therefore are often constructed differently. Except in rural areas, they tend to give access to fenced-in yards or gardens rather than the neighborhood at large.

Dog doors are found to be convenient by many dog owners, because it lets their dogs come and go as they please, reducing the need for trips outside and unwanted behaviour such as the dog scratching on doors or walls or excreting in the house.

Dog doors are generally designed to be safe for any pet. The panels are often designed with soft vinyl that does not trap or injure the dog. Dog doors also sometimes consist of permanent magnets to reduce drafts. Cheap, easily replaceable pet doors are made from plastic and as such are not robust enough for boisterous pets.

Patio door pet doors

Dog doors and cat flaps can be built into structures called patio door pet doors. These structures are intended to be installed in existing sliding patio doors so that there is no need to make holes in walls or wooden entrance doors. An advantage of the patio door pet door is that it need not be permanently installed; it can be transported with the owner when the owner moves to a new home. These doors can be made from thermo-plastics or aluminium and can be found in different colours to match the opening they are placed in.

Electronic pet doors

Several types of pet doors that allow selective access to pets are available. Some use a magnet or other triggering device mounted on the pet's collar to activate a mechanism that unlatches the door panel when the pet comes within range. Others are fully automatic and may allow access to the animal while keeping out strays and other unwanted animals. The advantages of this type of pet door are improved weather resistance and home security.