Fact #995, September 18, 2017: Electric Vehicle Charging at Home Typically Draws Less Than Half the Power of an Electric Furnace

September 18, 2017

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Electric vehicles can be charged at power draws comparable to various household appliances. Most electric vehicles charging at home on a 240-volt level 2 charger will draw about 7,200 watts or less. For comparison, a typical electric furnace draws about 10,000 watts and a water heater uses 4,500 watts. The power draw for an electric vehicle is limited by either the electric vehicle supply equipment (EVSE) or the vehicle’s onboard charger which limits the rate of electricity the vehicle can accept. Many first-generation plug-in vehicles have onboard chargers limited to 3,600 watts, similar to the power draw for a typical home air conditioning system, while newer electric vehicles have increased onboard charging rates. Some owners use only a standard 120-volt household outlet (level 1 charging) which has a very slow charge rate and low power draw compared to the level 2 charging. There are some electric vehicles, such as those produced by Tesla, that allow for even greater home charging speeds and higher power draws similar to an electric furnace. While an electric vehicle can draw a considerable amount of electricity when charging, the overall fuel cost for an electric vehicle is lower than a comparable gasoline vehicle.

Power Draw for a Typical Appliance

Graph showing power draw for a typical appliance (refrigerator, space heater, electric car-level 1 charging, air conditioner, water heater, electric car-level 2 charging, and electric furnace)

Notes:

  • Level 1 charging assumes the 12-amp setting is selected.
  • In colder climates, an electric furnace may draw 20,000 watts.
  • For comparison, a 2013 Nissan LEAF is rated at 115 MPGe (miles per gallon equivalent) and a conventional 2013 Nissan Versa is rated at 35 MPG. This results in a cost of 3.8 cents per mile for the LEAF and 6.7 cents per mile for the Versa at 13 cents per kW-hr and $2.35 per gallon of gasoline.

Sources: Water heater, space heater, refrigerator - U.S. Department of Energy, Estimating Appliance and Home Electronic Energy Use, accessed July 18, 2017.

Electric furnace and air conditioner – Email communication with the Program Manager for the Weatherization and Intergovernmental Program, Oak Ridge National Laboratory, August 1, 2017.

Electric car level 2 charging – Based on the charge rate of a 2017 Chevrolet Bolt and 2017 BMW i3 at 7.2 kW.

Electric car level 1 charging – Energy Use Calculator, Watts, Volts, Amps & Ohms Calculator. 120 volt outlet at 12-amp charge setting = 1,440 watts.

Text reference to Tesla vehicles – Technical Specifications, accessed July 20, 2017.

Note on vehicle fuel economies - U.S. Department of Energy and U.S. Environmental Protection Agency, Fueleconomy.gov, Compare Side-by-Side (Fuel economy).

Fact #995 Dataset

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