Lower core body temperature and greater body fat are components of a human thrifty phenotype
There is bound to be a lot of individual variability. We need more research using different sexes/age groups.
Since I've reduced my weight from 12stone 8lbs to below 10 stone 4lbs I've found I'm far more sensitive to room temperature (loss of insulation?) It will be interesting to see how it works out over the summer?