Exhaust & Supply air streams try to equalise to a common temperature, as they pass through the "core". The greater the temperature difference between the two air streams, the greater the efficiency of the heat exchanger. Whenever cold air is heated, its capacity to absorb moisture is increased. Warm air can absorb more moisture than cold air, and is thus dehumidified. Energy is required for the first "Heat up", after that, only minimal "Top up" heat is required, and existing energy, is continuously "recycled" reducing ventilation or process energy costs by 50% to 98%. HEATEX works with hot or cold energy.