A sampling of a number of frost issues. I’ve not included the door from Jan’s office to the storage that is a solid block of ice along the bottom nor the front door that we know needs a full length sweep.
Most of these appear to be air leaks (and yes, that is daylight that you can see between the sash’s and frames) either in the windows or the insulation. With many of these you can feel the air movement. The second from the right window in the Living Room gets frost on the lower part of the upper sash much more than the other four windows along there and it is also one we’ve had a lot of problems with.
The one exterior door that does not have frost is the LL Rec Room Sauna Patio door – which is also the door that is becoming increasingly difficult to open.
East and South facing windows have little to no frost. North facing are moderate. East facing are worst.