Looking for a bit of help here. I like to thinm I understand heat transfer and insulation fairly well but I can't wrap my head around this. Specifically talking about the cling film you install on your windows with soapy water. Yes I know about the draft stopper heat shrink film's and how they work.Typically these are sold as privacy film in various designs but they also claim to save energy. In the summer I could understand they might block a few wavelengths but if you tried to seriously tell me they were insulation I would have laughed. Here is the problem though. I have a 100 year old house with single pane windows. Basically a removable single glass and wood framed outer piece and then the more decorative glass and wood frame inner piece. Pretty typical. These get condensation on the inside when it gets very cold outside. Again. Pretty typical. Now during the recent cold snap I noticed that my windows without cling privacy film were starting to actually freeze. The ones with the privacy film had little to no condensation and didn't freeze at all until it was almost 15 degrees colder outside. Even when they did it was much less.Is this 1/16" of plastic in direct contact with the glass actually making that big of difference? It can't have much of any R value. Maybe it's just a really poor thermal conductor? Or is there something I'm not considering? via /r/DIY http://bit.ly/2Tr29oO
