A dog door is a small swinging door that, once installed in a door or wall, will allow your dog access to the outside of the house. This allows you to enjoy dinner, or your favorite movie, without being interrupted because your dog is adamant on having a stroll in the backyard. With a dog door, your dog has the freedom to move in an out of the house without someone's aid.

There are several different types of doors, from the basic models that make use of a mechanical flap to the deluxe ones that are radio wave operated.

The most common type consists of a single flap or door with a hinge at the top. The flap swings freely when pushed and falls back into place once the dog has passed through.

Dog doors also have a lock mechanism, which comes handy when you want to restrict your dog indoors or outdoors. Though quite helpful, conventional doors can be a nuisance at times, since stray dogs, raccoons and other small animals might enter your house.

Radio wave operated deluxe doors can successfully counter this situation. A small battery-operated transmitter on your dog's collar disables the lock when your dog nears the door. The door otherwise remains locked at all times, thereby warding off other animals.

Doors come in a variety of sizes to accommodate different size pets. Having chosen the style, you must ensure that the door is large enough to allow an easy passage for your dog. Certainly, you would not want your dog to get stuck in the door while walking out. Your dog should be able to tread through with ease by just lowering its head to push the door open.

Most doors are rather inexpensive. However, the electronic ones and those that are fitted in sliding glass doors may incur a higher cost. But cost should not be a major determining factor while choosing a door.

A durable and automated door, though expensive, will eliminate the need for constant supervision of your dog.