Ah, yes, because winter isn't miserable enough. >The relationship between thermal comfort and clothing weight explains why we tend to prefer a higher air tempe

Ah, yes, because winter isn't miserable enough. >The relationship between thermal comfort and clothing weight explains why we tend to prefer a higher air temperature to adding more clothing. [...] This clothing layer (which is actually worn in combination with briefs) has the largest potential to substitute a heating system. [...] Because it fits tightly around the body, long underwear has an optimal "pumping coefficient". When I was a child, we used to go skiing and then hang around in our long underwear. It is warm and flexible, but it's also tightly woven and form-fitting, which traps moisture inside. There's more to comfort than weight: even in a cold room, sitting with your back against the couch can accumulate sticky sweat. >Synthetic thermal underwear should be washed regularly - a process that consumes energy. This is less an issue for indoor use than for outdoor sports, because couch potatoes don't produce sweat. Anyone who's ever reworn a pair of sweatpants for a week inside knows intimately the rancid depths of this falsehood.