1. Each workstation is controlled by an on/off button mounted at the workstation, and two air flow sensors mounted in the ducts.

2. The extract and incoming air, is passed through segregated chambers of an alloy core air to air heat exchanger, warming the incoming air, and thus reducing the amount of energy required to heat the incoming air.

3. After the heat exchanger the extracted air is vented to atmosphere.

4. After the heat exchanger the incoming air is accumulated into a single duct and passed over elements to bring the temperature up to the desired temperature.

5. The incoming air is then segregated again, and distributed to various parts of the building.

6. Between the start and finish times as set inside the PLC, there is a minimum of ten litres per person per second introduced to the building. This is based on a staff of thirty people.