Having a window, or many in your dreams represents either one of two things. Depending on the state of the window.
If you’re looking through the window in your dream, it means that you either want something on the other side, or you’re just observing because of a certain feeling. It could vary in emotions from jealousy, approval, hatred etc. Depending on what you see on the other side, if it’s positive, then you either yearn for it, or you like it. If it’s negative it can associate with all the other negative emotions.
If you’re looking at a reflection in the window, it could mean that there should be a re-evaluation of yourself. You might see something wrong with yourself, or your conscious is telling you that something’s not right with the way you are presently, either emotionally or physically.