Subcooled Air Conditioning are specialists in all aspects of ventilation and extract systems. A more specialist system we have come across is the VAV (Variable Air Volume) system. This technique is normally integrated into the buildings fresh air supply. Fresh air is forced into your building which passes through a cooling/heating coil. This tempers the air to a set temperature. Air then travels through the building at a constant pressure. Within in each area are VAV plenums which are fitted with pressure dampers. These can be set manually to either reduce or increase air passing through the VAV plenums allowing variable room temperatures throughout the building and individual rooms. Below is a diagram of a typical VAV system which is cooled via a water chiller and heated via gas boilers. Other forms of Air tempering are available for these systems including DX (direct expansion) heat pumps. This method is alot more common now due to its efficiency and safety. Loosing the requirements for gas heating and relying on electric air source heat pump to supply both heating, cooling and hot water is considered the most efficient and effective when creating the perfect environment.