THERMOSTAT WITH OCCUPANCY DETECTION VIA PROXY

A controller for controlling an environmental condition of a building space includes a proxy sensor configured to measure a proxy value indicating whether an occupant is within the building space and an occupancy sensor configured to measure an occupancy value. The controller includes a processing circuit configured to determine whether the occupant is within the building space based on the occupancy value of the occupancy sensor, generate a proxy parameter based on a first proxy value measured via the proxy sensor in response to a determination that the occupant is not within the building space based on the occupancy value of the occupancy sensor, determine whether the occupant is within the building based on a second proxy value measured via the proxy sensor and the generated proxy parameter, and control one or more pieces of building equipment to control the environmental condition of the building space.