There are actually a lot of weak spots, like the vents, the aluminum window frames, door panel, appliance vents, etc. By doing what we can in areas that is easier to do so, we lesson the amount of heat loss (or gain).
I have the dual glazed window above our sink, and have never lacked for want of ventilation in our trailer. That would be one window that would be quicker to steam up when colder outside, whether cooking or washing dishes.
2017 Escape 5.0 TA (someday soon, I hope
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
“Most folks are about as happy as they make up their minds to be.” — Abraham Lincoln