It has also been suggested that the somewhat heated cowling air breathed by our RV-12 carbs serves to reduce the potential for carb ice. I'm not sure how much this helps, but IMHO it can't hurt in most situations. If an unheated ambient air source were to be used, a supplemental carb heat system (water, electric or exhaust pipe muff) might be appropriate.
ps -- For a real educational moment regarding how cold carbs can get while operating, just feel the temperature of the carb after its been running awhile - perhaps after a carb sync check. It is noticeably colder than the adjacent intake manifold. The carb/manifold rubber connector effectively isolates the carb from the engine's heat.