Do it yourself

Hello All, Once again, I pose a question. We just bought a house (end unit townhouse), in the master bedroom that is a small window (approx 18w x 36L). The window appears to be in good condition, i.e. all the glass is there, both panes, screens, no obvious seperation between the window and it's housing. But the previous owners framed in the window frame with 1x1's and used that second frame to hold a sheet of plactic. They also caulked in the 1x1's. It looks like an extremely elaborate version of "cover your windows with plactic to keep out cold air." I know this small window was near the head of their bed, but could it be possible then went to this much trouble because of cool air? The window doesn't look to be broken etc. Thanks for the help. Steve