I totally get what you mean about the cold just seeping through single panes, even with thick curtains. I actually tried one of those clear insulating window films before I could budget for double glazing. It helped a bit—definitely cut down on the drafts—but it didn’t make the room feel truly warm, especially on windy days. The film was kind of a pain to install too, lots of smoothing and trimming. Honestly, nothing came close to the comfort once we switched to double glazing, but the film’s not a bad stopgap if you’re not ready for a big upgrade yet.
That’s interesting about the window film—I’ve wondered if it’s actually worth the trouble. Did you notice any condensation issues with the film on? I keep hearing mixed things about that. Also, when you switched to double glazing, was it a huge difference in noise too, or just warmth? I’m still debating if it’s worth saving up for the upgrade or just toughing it out for another winter...