Originally Posted by drtravix

As for the 'how does the air leak in if the cabin is at a higher pressure' question...

I suspect the outside air really doesn't leak into the cabin - the insulation and seals on the door are just not so great, which allows the extremely cold temperatures outside to cool the metal exterior door, which then cools the interior metal (as the insulation is faulty) which then cools the inside air immediately near the door.