The variable air volume box is interlocked with a thermostat, and can then control the temperature in a space. As a space requires cooling because of a large cooling load, the damper in the VAV box will be placed in the "full open" position, to allow the maximum volume of air to enter the room, as shown in the left picture. As the space comes closer to its setpoint temperature, the damper inside the VAV box begins to close, thus decreasing the volume of air delivered to the room, as shown in the second illustration. The damper may close to provide only 15-30% of the original design cfm for a space. By regulating the volume of air delivered, a variable air volume system can control the temperature of a space without changing the temperature of the supply air.