Do it yourself :
If you do not want professional help or think it will make the project an expensive one. Go for a cat door that is a do to yourself one with the whole manual and installation method in the package. It is a small project that will not take more than a vacant afternoon.
The size of your pet determines the size of your cat door. An over sized cat door can increase the risk of any burglary while a smaller one will make movement difficult for your pet. It is better to get a standard size because even if you have a small kitten, it will eventually grow up.
Windows are constantly exposed to outside weather elements, be it rain, sunlight or wind. You need to look for a cat door that is weatherproof so that it serves you for a long time.
Shape and color:
Cat doors come in different shapes, square , circle and even cat shaped. The shape of the door depends entirely on your own preference and the shape of the window.
Choose the color of the cat door according to the theme of the room and the color of the windows or curtains.
Most pet doors come as plastic flaps which close naturally after the cat has passed through. These are the most common ones. There are others with springs and catch.
However, it is necessary that you get a door that has a locking mechanism of some sort so that you can control the movement of your pet, especially during the nights. A lock also proves helpful if you are going out of the house with your pet for an extended period and want to shut off everything.