Body heat as a factor in temperatures

[mumblemumble]

it strikes me now, that body heat is non existent in the game...in reality, its a pretty big factor, closed rooms with no ventilation and lots of people are incredibly hot, which can be either a pain, or very helpful in the cold.

Really, I doubt it would be TOO hard to do, to make humans, and animals generate a very small heat signature. Would be interesting, especially a pack of animals making a barn hot.