A masterless building device system for controlling an environmental condition of a building, includes a first building device and a second building device. The first building device includes a first processing circuit configured to determine, via a first sensor of the first building device, a first environmental condition value of the environmental condition. The first processing circuit is configured to broadcast the first environmental condition value to a second building device via a network. The first processing circuit is configured to receive, via the network, a second environmental condition value broadcast by the second building device, generate a calculated environmental condition value based on the first environmental condition value and the second environmental condition value, and control the environmental condition based on the calculated environmental condition value.