Many homeowners in damp climates such as Oregon keep mold at bay with an electronic dehumidifier. These tend to be large, loud devices. We wondered just how much energy a dehumidifier uses? To find out, a Watts Up Pro was used with a LabQuest interface to collect real-time power consumption data. A Relative Humidity Sensor was also connected to LabQuest to monitor the relative humidity, which is the amount of water vapor in the air compared to the maximum amount it can hold.
The power data show that when the compressor is on, it draws a whopping 470 watts. The fan also runs for several minutes after the compressor shuts down, which is the middle level of energy use near 200 watts. Note that even when the dehumidifier is nominally off, it still draws about 3 watts. Because of the noise, the dehumidifier was turned off at night, yielding the long, low-energy spots in the graph. It is also interesting to note that the relative humidity quickly climbs during these periods.