DuPont™ Tyvek® ThermaWrap® LE is made with a metallized, low-emission (low-e) surface that reflects solar radiation away from the building. In cold weather, this helps prevent radiant heat loss from within the structure. In warmer weather, Tyvek® ThermaWrap® LE turns the tables, reflecting warm air out and away from the structure, to help improve air-conditioning efficiency. In all seasons, that can help make both residential homes and commercial buildings more comfortable, more energy efficient, and less costly to operate.