This has to be it. This evening I decided to open the windows and door and turn off the space heaters. Within a few minutes it felt warmer in here.
It might not even be that dry where I am. The weather sites say the humidity is 13% in Ensenada right now, but who knows where they take the reading. I might be close enough to the ocean that the air is actually not that dry.
This is why I can step outside, into the shade, when it’s 45 degrees out, and feel warmer than I do inside.