More generally, the climate in which a person rests, hence the temperature between the mattress and the duvet is conditioned by the delicate balance between the extremes of too hot and too cold. In fact, if moisture remains on the body during sleep, it causes feelings of cold and discomfort. That's why the correct choice of the duvet is fundamental: the duvet has a high capacity to absorb moisture and to eliminate it quickly, returning it then to the air. In what kind of way is this happening? To understand the function of a duvet it is sufficient to think of the system that is used in construction to insulate the interior part of a house from the outside, that maintains a gap or an "air passage" between the windows and walls. The finest burbs of the down tufts are able to retain air. Since the air is an excellent insulator, the duvet has the ability to collect and store the heat released by the body during the night. In this way it protects us from the cold and offers a pleasant and constant temperature during sleep.