a little difficult to answer the definition of "at the lowest level" is difficult to define for this unit (depending on the fan setting and the desired humidity). the manufacturer's specification is 25W and that is probably meant as the maximum, but i think the consumption is normally a lot lower. i do have a wattmeter, but it is either defective or the device needs so little power that it cannot be measured. in principle, it is also just a fan with a sensor.