According to the U.S. Department of Energy, typical humidifiers use 785 watts of electricity. Costs to run household appliances vary depending on a number of factors. Older appliances generally cost more to operate due to energy-efficient features added to later models.
To calculate how much a humidifier costs to run, multiply the wattage by the hours and days of operation, then divide by 1,000. Multiply this number by the cost per kilowatt hour the electric company charges to find the estimated total cost.
The total cost varies depending on region. According to the U.S. Energy Information Administration, some states such as Kentucky and Louisiana offer rates between 7.33 and 8.30 cents per kilowatt hour, while other states such as Alaska and Vermont see prices between 12.42 and 34.80 cents per kilowatt hour.