The Humidifier+ is capable of humidifying your room for up to 8 hours. Do not humidify to indoor relative humidity levels exceeding 50 percent. Hygrometers, available at local hardware stores, may be used to measure humidity levels. You can also use the Dream Machine, if you have one, to check the Humidity and Temperature within the room. If there are signs of any condensation within the room then the humidity is already high so do not use the humidifier until the humidity level is low again.