How do you read the energy usage of an appliance?

Electricity is metered in killowatt hours. 1 kWh is equivalent to using 1000 watts for one hour. A powerful hair dryer might use 2000 watts so using it half an hour would use 1 kWh. A laptop might use 50 watts while being actively used so it would take 20 hours of use for it to use 1 kWh (when not in use most laptops go into power saving standby, sleep or hibernate modes). In most of the US electricity costs from $0.10 to $0.20 per kWh. In remote or urban areas it can be over $0.40/kWh while some locales near hydroelectric plants pay only a nickel. It is hard to say exactly how much power a dehydrator uses; they have thermostats so it doesn’t draw current the whole time it is in use. Mechanics have a saying, “One measurement is worth a 1,000 expert opinions.” There are small kWh meters for appliances. Kill-A-Watt is one brand. If you plug an appliance into one of these it will tell you how much power it consumes. Power meters usually pay for themselves by helping consumers use electricity more wisely. You can buy or build a solar dehydrator. All these require is a sunny day to do the job.