A thermostat may include a proximity sensor and a temperature sensor. The thermostat may also include a sensor mount assembly containing the proximity sensor, the temperature sensor, and a first alignment feature. The thermostat may additionally include a lens assembly having a first area, a second area, and a second alignment feature, where the second area includes a Fresnel lens, and the first area is thinner than the second area. The thermostat may further include a front cover where the outward-facing surface of the lens assembly is shaped to continuously conform to a curvature of the front cover. The thermostat may also include a frame member with third and fourth alignment features configured for respective matable alignment with the first and second alignment features and configured such that the proximity sensor and the temperature sensor are maintained in generally close, non-touching proximity to the lens assembly, the first area of the lens assembly being aligned with the proximity sensor, and the second area of the lens assembly being aligned with the temperature sensor.