Fresh Air Ventilation and Heat Exchange unit - SAF-E7 - The SAF recovers heat energy which would otherwise be exhausted to atmosphere, and uses this energy to warm the air entering the building. the reverse happens in warmer climates, where the exhausted cool air is used to partially cool the incoming air. - Capturing this waste energy, means the heating/ cooling requirements of the Building are Reduced, so smaller size plant can be selected, Savings can be made in long term energy consumption, and carbon emissions are reduced.