In many homes, heating and air conditioning systems consume the most energy because they run for long periods. U.S. energy data shows that space heating and cooling together account for more than half of average household energy use. Air conditioning is also the largest single use of residential electricity nationally.
Electric water heaters can also create a major expense. Water heating accounts for roughly 13–20% of home energy use and is often the second-largest energy cost after heating and cooling.
Small heating appliances such as electric ovens, tumble dryers, kettles, space heaters, and hair dryers can draw a great deal of power while operating. However, something that consumes heavily “per minute” may still cost less overall than an air conditioner or water heater that runs for hours.
To identify the real culprit, compare several electricity bills, inspect appliance energy labels, and use a plug-in energy monitor for suitable devices. Sudden increases may also indicate a failing water heater, faulty thermostat, inefficient heating system, or appliance left running.
No single appliance secretly doubles every bill, but heating, cooling, and water heating are the best places to investigate first.