Is That Saran Wrap?

I came home from work one evening the winter before last and there was this coating on the inside of the windows.  Wynn had been home from work all day and she is known for her creativity.  So I being a bit daft from time to time asked her the following question.  "Is that Saran wrap on the windows?" and the answer was obvious.  "No, it's to keep the cold air out."  No it wasn't Saran wrap it's actually something sold at home improvement stores to keep the cold air out if you have leaky windows.  I was surprised but it did actually work quite well, I'm not sure why we only used it for that first winter.  I guess it had to do with me tearing it down to open the windows when the first hints of spring arrived.