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Installing a cat-flap in your door is a simple procedure. However, you'll need to know a few things before getting started. Upvc door panels that have an opening for cats can be installed without needing to cut holes in your wall or door. Many glass companies provide them with holes already cut to fit a pet-door. 1. Safety Upvc door panels cat flaps are simple to put in and can be fitted to many different types of doors. They are energy efficient a