This was in context to someone in a house with proper heating, but still feeling cold.
I learned from a swimming teacher "water transmits heat/cold 10 times faster than air", therefore a logical conclusion is that dry air is insulating more than moist air.
Heat and cold transfer in air happens, just take your shirt off, you feel the temperature change immediately. Go to a very, very cold climate with dry air, if there is no wind, it truly doesn't affect you that badly. Same with Arizona in the summer ("it's a dry heat" is a state motto, IIRC)