An HVAC sensor device comprising: - a control signal input configured to receive, from an HVAC controller, control signal(s) for controlling one or more HVAC actuator(s) of an HVAC system; - a control signal output configured to transmit control signal(s) to the HVAC actuator(s); and - an electronic circuit configured to: - receive a sensor signal(s) indicative of condensation and/or relative humidity in the HVAC system; - pass through the control signal(s) received at the control signal input to the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is within a defined range(s); and - overwrite the control signal(s) received at the control signal input with a control reference value and output the overwritten control signal(s) at the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is outside the defined range, which control reference value - when received by the actuator(s) - causes the HVAC actuator(s) to move an actuated part to a safety position which reduces and/or prevents formation of condensation, wherein the control reference value is within a value range of the control signal. - a control signal input configured to receive, from an HVAC controller, control signal(s) for controlling one or more HVAC actuator(s) of an HVAC system; - a control signal output configured to transmit control signal(s) to the HVAC actuator(s); and - an electronic circuit configured to: - receive a sensor signal(s) indicative of condensation and/or relative humidity in the HVAC system; - pass through the control signal(s) received at the control signal input to the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is within a defined range(s); and - overwrite the control signal(s) received at the control signal input with a control reference value and output the overwritten control signal(s) at the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is outside the defined range, which control reference value - when received by the actuator(s) - causes the HVAC actuator(s) to move an actuated part to a safety position which reduces and/or prevents formation of condensation, wherein the control reference value is within a value range of the control signal. - receive a sensor signal(s) indicative of condensation and/or relative humidity in the HVAC system; - pass through the control signal(s) received at the control signal input to the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is within a defined range(s); and - overwrite the control signal(s) received at the control signal input with a control reference value and output the overwritten control signal(s) at the control signal output if the sensor signal(s) indicative of condensation and/or relative humidity is outside the defined range, which control reference value - when received by the actuator(s) - causes the HVAC actuator(s) to move an actuated part to a safety position which reduces and/or prevents formation of condensation, wherein the control reference value is within a value range of the control signal.