That's a good question- Most parents will tell you to wear a hat on a cold day because they know that some 40% of bloodflow goes through the head and lots of heat is lost upstairs.The company is Otter Bay. Cricket will make a 12mm hood custom fit to your noggin.
The first thing I thought when I read this thread was "what kind of hood is he using?"
Does anyone have any comparisons between warmth with different hoods while using the same undergarments?