A thermostat may include first and second solid-state switching elements coupled to a call relay wire connector and a power return wire connector. The switching elements may be configured to operate in a first state to make a connection between the call relay wire connector and the power return wire connector, and a second state in which the connection is interrupted. The thermostat may also include power monitoring circuitry configured to cause the switching elements to operate in the first state to actuate an environmental control function, receive an indication that the switching elements should transition to the second state, at a first time after receiving the indication, turn off whichever of the first switching element and the second switching element receives AC current from the environmental control system at the first time; and at a second time after the first time, turn off the other of the switching elements.