Look at the wattage listed on your dehydrator.

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Mine is 425 watts, which means that it uses 1 kilowatt/hour of electricity (about 13 cents here) every 2.3 hours. So keeping it on costs about 6 cents per hour.

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Your dehydrator could be broken or have a short, but there's probably a different reason your power bill is high. You could always check it with a watt meter like this one https://www.amazon.com/Upgraded-Consumption-Electricity-Overload-Protection/dp/B07P8M7N9F/

$15 is cheap troubleshooting for this problem.