I rented my apartment in the summer, now with the cold weather starting (Australia). I noticed how cold the toilet window makes the apartment, there is zero isolation, and is basically a window with separated glasses to the outside (second floor).
I want to install a second window that fits on the whole frame for the old window, maybe with just a frame and plexiglass or glass.
So my question is, how to make this isolation window so is easy, cheap. That I can install and uninstall (when the summer comes again).
Is there a preferred solution for this case?
Thanks in advance.