I connected the meter to a dehumidifier in the basement. After a few days, it showed some impossibly large amount of electricity used, and even though the dehumidifier wasn’t running, it showed that it was drawing something like 1900 watts, when its normal usage is less than 600, and then only when it was actually running. I called the manufacturer, who told me that I would need to use a power line filter, because the error was probably due to noise in the power line. Noise can be caused by common devices such as motors, so the compressor and fan on the dehumidifier could have been interfering. A common example of noise is when a hair dryer or vacuum cleaner causes problems with the sound or picture on a TV or the sound on a radio (especially AM radio). Another thing they recommended was to erase all the old data from previous users, to allow the meter to collect more data points for the current user. Otherwise, it won’t collect much data, in order to preserve all the data that’s already there. This means that people who use the meter will likely need to buy a power line filter or have the library supply one. I don’t know which filter is the right kind, and how much it would cost. Online, I saw filters ranging in price from $10 to over $100.

posted Aug 19, 2010 at 6:34PM

Does your dehumidifier have a heating coil to melt the frozen condensation off the collection coils? The 1900 Watts sounds suspiciously similar to what a heating coil would draw.....If it’s an old one they typically kick in automatically and don’t have any sophisticated sensor to detect whether the heating coil is needed, they just cycle back and forth. A real waste of energy.

posted Sep 10, 2010 at 3:03PM

I measured a line with a dehumdifer an extra fan and a few lights and the meter seemed fairly accurate. I did notice the max reading seem to shoot up an extra 500 watts probably due to the start up surge on the DH.

posted Nov 14, 2012 at 9:18AM

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