
Part of the chill factor is that old problem of "single glazed" RV windows. Sure, some manufacturers include "storm windows" on their rigs, but by far, most of us just have that single sheet of clear stuff between us and the outside world. What's to do if you've got too much cold coming through the glass? Add your own "storm window" with shrink-fit window insulation. You can buy this stuff at nearly any hardware store or home center.
Besides the window insulation kit you'll also need scissors and a blow dryer. Some RVers say that they use an electric space heater to "shrink" the plastic into place. If you try that trick, start at a considerable distance away from the plastic lest you find the source too hot and burn a hole in your plastic, rather than shrinking it into place.
Here's a little video that shows you the basic principles of installing the stuff. However, instead of sticking the sticky tape away from the window, most of us can stick it directly to the window unit itself. You may need to "work around" problems like window cranks. We might add too, that the video makes it appear that there's a lot of left over wrinkles in the finished product. We're not sure if that's an illusion, or if our "installer" just didn't work long enough on getting the wrinkles out. With effort, your final product will be flat, tight, and highly viewable.