1. An HVAC data processing and communication network, comprising: a first subnet comprising a first subnet controller, a first comfort sensor and a first user interface coupled via a first data bus; a second subnet comprising a second subnet controller, a second comfort sensor and a second user interface coupled via a second data bus; and a switch coupling said first data bus to said second data bus, said switch being configured to decouple said first data bus from said second data bus upon receiving a command from said first subnet controller.