There is no doubt that uPVC windows are more secure than timber frame windows. Timber has a habit of rotting over a period of time making the wood easy to break or manipulate. As a timber window frame weakens the more it compromises the security of your house. While you are away for the weekend or on your summer holidays a burglar or a housebreaker can sneak into your garden and use a pry bar to gain entry to your house via your timber frame windows.