page 2019 (8 of 18) of

http://www.ms-se.com/pt/pt-core/template-journal/msse/media/1106.pdf

quotes an interesting statement from a study in 1957.

"This means that at –4°C the heat loss from the head may amount to half the total resting heat production of the man."

http://jap.physiology.org/cgi/content/abstract/10/2/235

50% of RESTING heat production.

i think i'll keep my beanie on, thank you very much.