EV Charging Consumes Less Energy Than Water Heating In Typical US Home

7 days ago by Mark Kane 48

Electric Vehicle Charging Consumes Less Energy than Water Heating in a Typical Household (source: energy.gov)

The US DOE’s Office of Energy Efficiency & Renewable Energy reports that electric vehicles are the biggest user of electricity in household – provided you don’t use any electric heating for your furnace or water.

2018 Nissan LEAF charging

The report states that the average electricity usage in a typical household for heating (furnace and space) is 11,300 kWh, while water heating is 4,700 kWh.

The electric car (data based on Nissan LEAF usage via EV Project) consumes some 2,800 kWh every year (for 9,697 miles of travel), which is basically twice that of what a refrigerator needs.

“Charging an electric vehicle consumes less energy than several common household appliances.

Annual energy consumption for a typical household shows that home heating consumes by far the most energy (11,300 kW-hrs) followed by water heating (4,700 kW-hrs) and charging an electric car (2,800 kW-hrs). Based on average driving habits and consumption rates for the Nissan Leaf, charging an electric car consumes just over twice as much energy as a refrigerator which consumes about 1,300 kW-hrs annually. While an electric vehicle adds to household electricity usage, it eliminates the need to purchase gasoline for that vehicle which would cost considerably more based on national average gasoline and residential electricity prices.”

Notes:

  • The electric car data are based on a 2013 Nissan LEAF driven 9,697 miles per year which was the average annual mileage of a Nissan LEAF in the EV Project.
  • 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.
  • Data in the 2009 Residential Energy Consumption Survey are presented in British thermal units (Btu) and represent site or delivered energy (1 kW-hr = 3,412 Btu).

source: energy.gov

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53 responses to "EV Charging Consumes Less Energy Than Water Heating In Typical US Home"

  1. Bar says:

    That graph is missing a bar for the average gasoline car (to put things even more in perspective).

    1. Brave Lil' Toaster says:

      Indeed! +1!

    2. F150 Brian says:

      Using the comparison from the article, the Versa would be ~9200 (115/35*2800), which is still a lot less than space heating.

      A house in the northern US or Canada heated by a high efficiency furnace (95% AFLU) emits several times the amount of CO2 than the average ICE vehicle. Imagine how bad a 60% efficient furnace is.

      In a northern climate, converting a gas or oil furnace to electric would do much more for the environment than converting cars to electric. The house already has a connection to the grid and the electric core for conversion is $125.

      But logic rarely influences action in our society.

      1. Bruno says:

        I did that, but a lot of people prefer status quo, Quebec low electricity rates sure helped me in the process thought…

      2. Djoni says:

        Well, converting equivalent energy per volume of gas, the Versa use 9 337 kWh of energy to traval 9 697 miles.
        Which is for simplification, in the almost the same quantity of energy for heating your average house.

        F150 Brian, 125$ for an electric core?
        No way, if you include labor, duct work, electrical supply and upgrade.

        Still you point is valid in a broder sense of getting Co² level down, althought, heating is about the only place where burning fossil fuel is very efficient.

        1. Bruno says:

          Don’t confuse efficienty and cost, electric furnace are 98%+ efficient, its just that the electricity is more expensive

          1. Nick says:

            Right! I’d be in the poor house if I tried to heat my house with resistive heating.

            I don’t have to pay for the damage that I cause by realising CO2 when I burn natural gas, so that’s much cheaper.

          2. Mint says:

            98% is actually quite inefficient.

            Heat pumps can often get a COP of 4, i.e. you home is heated four times as much as the energy you put in.

            1. Pushmi-Pullyu says:

              Using the word “efficient” (or “inefficient”) to mean something different than the meaning used by the person you’re responding to, as you did here, will merely lead to a lot of pointless arguments.

              There’s an excellent reason why traditional energy accounting never allows for the efficiency to be 100%… because you always lose some energy in the process. Basic Second Law of Thermodynamics.

              If your accounting results in an energy “efficiency” figure greater than 100%… then you’re no longer actually talking about efficiency. You’re talking about something else, such as the ability of that heat pump to move heat around. It may be appropriate to call that effectiveness, or some other term; but it’s not efficiency.

              1. Just_Chris says:

                Using an efficiency calculation and argument for a heat pump vs a restive heater vs gas boiler is fraught with all kinds of pitfalls. The restive heater will be the most efficient, then the gas boiler then the heat pump. With the heat pump needing the greatest energy input per unit heat by a long way BUT! before everyone jumps down my throat who cares if the heat pump is not as efficient if the fuel is air? In fact if you wanted to increase the efficiency of the heat pump you’d reduce the air flow and increase the pressures which would increase the electrical input. That would be dumb in the extreme as air is abundant and free where as electricity is comparatively expensive and scarce.

              2. John in AA says:

                Thank you.

              3. Mint says:

                I’m sorry, but I just can’t agree. Efficiency is getting maximum return for minimum input, regardless of the topic. Same thing with energy efficiency.

                If you want to keep a house 20 degrees when it’s sitting in zero degree weather, thermodynamics says the best you can do is put in about 0.11kJ of work for every 1kJ of heat loss through the insulation.

                That means a so-called 98%-efficient resistive heater is really only ~11% efficient. A heat pump can be 20-40% efficient.

                Just_Chris, I have no idea why you think “the heat pump needing the greatest energy input per unit heat by a long way”

      3. Tom says:

        Your claim is categorically false. Let’s just take coal off the table because then it’s obvious. But if you compare gas to gas then an electric furnace is way more CO2 than a gas furnace. A 90% or better efficient gas furnace (anything built in the last 20 years for sure) compared to electric heat from a utility that uses gas to generate electricity will end up being way less efficient and more CO2 to use the electric heat. The losses in transmission alone for the electricity are very high.

        Bottom line is if your goal is to create heat such as either water heater, stove, or furnace, it is ALWAYS significantly more efficient and less CO2 unless the power source from the utility is renewable.

        1. Pushmi-Pullyu says:

          Nobody died and appointed you the King of What We Are and Are Not Allowed to Discuss on InsideEVs.

          You don’t get to dictate that we have to restrict the discussion or debate only to regions where they use rather little coal and rather little renewable energy.

          For those of our Canadian neighbors living in several provinces, as well as those living in Washington State and Oregon, up to ~90% of grid power comes from hydro. So your argument fails when it comes to them.

          And here in the Great State of Kansas, fully 54% of our grid energy, unfortunately, comes from coal. So your argument doesn’t apply here, either.

          1. Oswald says:

            All of that hydro is used by neighboring provinces and states. If you’re wasting it heating your home rather than using a more effective heating fuel such as natural gas than you are denying clean electricity to your neighbors. Washington has a ton of hydro, but if everyone converts to electric heating, what electricity will they use to charge their cars? It’s not an infinite resource.

            Likewise, Quebec sells their excess hydro-derived electricity to New York. If everyone converts to electric heat in Quebec (which many are) New York will receive less renewable energy, making every electric vehicle in New York less clean. Quebec’s initiative to convert to electric heat is an economic one, as they usually sell their excess electricity at below market value just to get rid of it to balance the grid.

            Devoting renewable energy to clean transportation is a much bigger win for the environment than switching an efficient natural gas furnace to electric. Our renewable resources should be prioritized by their most effective environmental use.

        2. Mark.ca says:

          I think Tom believes that the gas he uses to heat his house is sucked out of the air by his furnace. Wake up man, gas has loses too and most way before the fuel gets to the electric plant. It’s cheap that’s why we use it.

        3. Bill Howland says:

          Tom, you are just merely making the verified point that use of a fuel directly such as with gas heating appliances is the most efficient ‘Wells to Wheels’ application, if you are getting your energy from the grid. I’m over 100% solar electricity at my home, yet the majority of my energy comes from natural gas since I live in a cold climate. However since I MAKE SO MUCH SOLAR ELECTRICITY in the summer time, I effectively don’t use my cooking appliances during the summer season, and since I have my gas-fired tank-type water heater extra insulated and no hotter than I need it to be, the gas company keeps writing me letters saying there must be something wrong since I couldn’t possibly be using so little gas. And that is with 8 working gas appliances.

          They even sent a man over with a camera to photograph the entire installation around the meter as well as the meter reading itself to make sure there was no fraud being committed.

          But you know that the point you are making is correct since it is the same point make by all the natural gas companies on all their advertisements. Be comfortable in the knowledge your statements about Natural Gas are accurate. Its not worth arguing the point here. I of all people know.

      4. John Mausen says:

        In a northern climate, driving an EV during a cold winter day will reduce the total range of a Tesla to 80-90 miles and you will die of hypothermia while waiting for a toe truck.

        1. Get Real says:

          Troll alert.

          It seems that Canada has some of the same misinformed or outright lying stupid right-wing nut-jobs that have become to common and enabled here in the US.

          Probably because the same corprate fascist billionaires like the Kochs and same alternative “facts” propaganda sites they fund like Breitbart are growing there too.

          Reminds me of this Canadian idiot rascist gone viral:

          https://www.google.com/amp/www.firstpost.com/world/video-of-canadian-sikh-politician-jagmeet-singhs-calm-response-to-racist-rant-by-woman-takes-social-media-by-storm-4029533.html/amp

        2. Mark.ca says:

          Adults talking here…

  2. GuyMan says:

    What sort of refrigerator do most folks have – I have current measuring devices on most of my circuits, and my kitchen frig clocks in at 711 annual KWh, and a garage freezer is around 500 KWh

    Even an electric dryer for a family of 4 only is 707 KWH – 2800 KWH would be my peak load, though my heat pump is my current (pun intended) peak at around 2600 annual KWH

    They must be doing benchmarks against 30 year old refrigators

    1. SparkEV says:

      It depends on how often you open them. Mine clocks in at 3 kWh/day for fridge and 1 kWh/day for freezer, both averaged over a week. I suspect more for fridge with bigger family since the door will open more often.

      1. Doggydogworld says:

        Opening the fridge door doesn’t have that much effect. This study (PDF file):

        http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1835&context=iracc

        says opening 40x/day causes 20% of energy use. So raising it to 60x/day or cutting to 20x would be a +/- 10% change in energy use.

        NOTE: the study kept the door open for 20 seconds, but 10 and 15 second open periods didn’t change the numbers much.

    2. Alaa says:

      +1
      My fridge here in Cairo Egypt is a Samsung inverter, and it uses 35 kWh / month So that is 35 X 12 = 420 kWh per year. I however use 2 solar panels 250 Wp each and run the fridge lights washing machine and dish washer on just these 2 panels. I made a battery pack from old lap top batteries. About 1000 of the 18650.

      But it is a nice opportunity to show others that if the Leaf consumed 2,800 kWh per year, then if you live in a sunny country like Egypt you will have 3,400 sunny hours per year. So just 1 kW of solar panels will produce more electricity than what the car uses in a year. That is 4 panels at a cost of around $300. Here is a link for the solar panels around the world to show you that a kW costs around $300 and can be less. https://www.enfsolar.com/pv/panel

      Now if you think about it, this kW of solar panels will produce electricity for 25 YEARS So in theory you can charge or run your car for just $300 for 25 YEARS. In practice I would buy a 10 or 15 kWh battery for $3,750 from BYD and add $1,000 for more solar panels and a good inverter for another $1,000 so all in all we get $5,750. In the US you will get a tax credit of 30%. So out of pocket that is $4,025. This way I will run the house and the car for 25 YEARS for just $4,025. I chose 15 kWh battery so I can charge the car at night from the electricity I produced during the day. According to the numbers here 2,800 kWh per year is about 8 kWh per day for the Leaf. So 8 kWh for the car and the rest to run the house at night. Just how much did you guys in the US pay for gas and electricity per year say 3 years ago? I will tell you. 30 kWh per day X 365 X $0.12 = $1,314 per year. That is on the conservative side. Add $200 gas per month that is $2,400 per year. So you see $1,314 + $2,400 = $3,714 per year. Almost $4,000 in just ONE year. And a simple system for almost the same money will keep you going for 25 YEARS.

      1. David says:

        Thanks Alaa, nice contribution to the conversation. EV + solar is a very exciting combination!

        1. Alaa says:

          Thank you for thanking me David. I wish to add that if you buy a used EV that meets your needs then this will be the best investment. I personally am waiting for a 400 to 500 km range car that is used. It should be less than $10,000. Having said that a new LEAF that has a sub 100 miles is now selling for $10,000 in the US. I suspect that no one will buy them. So in theory that 100 mile range used LEAF should be less than $5,000. At any rate $4,000 for the home + $6,000 used car = $10,000 will give mobility and almost free heating and cooling, lights etc for many years. I suspect that the building codes of new house will have a built in system. I also suspect that there will come a day that we buy cars fully charged and trash them when the battery is empty like the pens we buy today. Who knows what the future holds!

    3. mr. M says:

      “The electric car (data based on Nissan LEAF usage via EV Project) consumes some 2,800 kWh every year (for 9,697 miles of travel), which is basically twice that of what a refrigerator needs.”

      Twice as much, what is the US doing??? The average household in europe uses 2.500kWh/a for electricity. No way the average household uses more than half of the electricity for the Refrigerator.

      A comparison: We are a familiy of four with a refrigerator, a fridge, a dryer, a dishwasher a washing machine that use propably the most electricity among other electric stuff we have. The average consumption of electricity of our appartment is around 2.250kWh/a.

      Please start saving the planet by ordering new fridges for the US first. That seems cheaper and faster to me than making the decission to buying a EV.

      1. Reply says:

        Outdated DOE numbers, likely from 2009, are used here for refrigerators (typically a combo refrigerator-freezer unit in USA) and hot water use. DOE/EIA is slow to update and great changes have occurred in products and consumer behavior/finances since then. Heating and cooling numbers are probably closer to reality.

        Latest number from 2009 show 89.6 million BTU (26,253 kWh) total ave. energy use per housing unit, which is outrageously high. We used 9,903 kWh last year, if you don’t count the Nissan Leaf. I suspect the next set of numbers from DOE will be substantially lower.

        Unfortunately, those with the oldest and least efficient appliances are often seniors and/or poor and/or in rental units controlled by landlords.

        There are also plenty of USA households with a second old refrigerator and/or freezer in the garage plugged in and chilling the beverages and clearance priced meat.

        Lastly, USA primary education system is generally poor when it comes to teaching about energy, electricity, pollution, etc. I’m not sure if this is by design, or it’s just a consequence of the “teaching for the test” mentality.

  3. DJ says:

    These reports are always such BS. As always it would depend hugely on what you drive, how much you drive, and what you use to heat your water.

    All one has to do is install a water heater with a heat pump and voila the electricity consumed is less than the Leaf at 10k miles a year.

    1. Mark.ca says:

      So you want them to do a comp study on things that are not usually found in a household? You do realize that heat pumps are barely making their way into homes now and most don’t have one, right? Of course it depends on how much you drive, that’s why they take averages….jeez, dude!

      1. Asak says:

        To be fair, it’s probably likely that someone buying an EV will also be the same sort of person who’d buy a heat pump water heater. They are significantly more efficient. Standard electric water heaters really are crap.

        1. Mark.ca says:

          Yes, if they need one they do buy. I have solar and an ev but still use a gas water heater and furnace. There are some that are tree huggers and some that just want to save money. I like to believe i’m a tree hugger myself but i’m not so sure i actually am one.

  4. Alan says:

    Hmmm ….

    I think our numbers come out to be:

    Home Electric Usage: ~6470 KWh
    BEV: ~3000 KWh

    leaves 3470 KWh for our li’l 900 sq ft home in Northern Coastal California … that includes A/C, Refrigerator, Laundry … water heater and furnace are gas. Menlo Park isn’t terribly hot in the summer, and our house is very well insulated. I was just surprised to find that the rest of the house takes slightly more than the car … I thought our house was extremely efficient … I think it still is, but now that I run the numbers, I’m surprised it uses more than our car.

  5. Priusmaniac says:

    One ev = two fridge is a really good comparison easy to explain to anyone.

    As a side note it is worth mentioning that water heating can be improved with different systems like solar heater or heat pumps but there is one thing that is even simpler and always applicable whatever the heating method, it is waste heat recovery.
    Here are links that explain it and show some of the ones available:

    http://www.renewability.com/power_pipe/what_is_dwhr.html
    https://database.passivehouse.com/en/components/list/heat_recovery

    1. Doggydogworld says:

      Large (22-25 cu ft) new Energy Star fridges are ~600 kWh/yr. Two of those will get you about 4000 EV miles.

  6. Mark.ca says:

    Fridge seems a bit high unless they are counting a second garage freezer which some have. Mine is a big 15 years old and consumes barely over 800/year. My ev is at 2400/year including 10% losses.

  7. Kosh says:

    Our data point:
    – passive solar house (not furnace or A/C)
    – on demand electric water heater (whole house)
    – 2013 Nissan Leaf drive ~ 45 miles/day (12kWh/day)
    – 43 solar panels

    picked a random day last december:

    – Car charging: 13 kWh
    – Water heating: 5 kWh (3 adult showers)

  8. ElectricAll says:

    Funny, I just replied to this same topic on GCC site. Again:

    All electric home, three people, 2,200 sf, lower Midwest USA.
    Heat Pump- 4,591 kWh
    Resistance 50 gal. Water Heater- 2,834 kWh
    Refrigerator (circa 1999)- 545 kWh
    Everything Else in Home- 1,933 kWh
    Leaf (8,100 m/yr.)- 1,728 kWh
    Total- 11,631 kWh

    Water saving devices and techniques make for a big reduction in energy use from DOE numbers. HPWH or solar hot water would be even better.

  9. Brave Lil' Toaster says:

    We have an electric hot water heater at home, and I would definitely say that this is accurate. We don’t measure what each individual appliance consumes, but I did a quick analysis of our power consumption, and there’s a big hole where our hot water heater is. So yeah, it makes up a large portion of our household consumption.

    This sounds about right to me. I know our Leaf’s consumption, and it’s only about 15% of our total household consumption.

    1. Kosh says:

      yes, electric tank heaters are hogs. You need an on demand (we have Steibel-Eltron) or a heat exchange electric WH that is 3 times as efficient as the on demand actually.

      local util may even pay to have you swap out.

    2. Asak says:

      You should consider replacing your water heater with a heat pump water heater. It will pay off fairly quickly as they are MUCH more efficient.

  10. wavelet says:

    Useful numbers to figure out what circuits a dwelling/neighborhood needs to support one urban EV… Not useful in the context of overall energy budgets.
    At the very least, to add to the comparison an EV used like a “normal” car, they should have provided a kWh number for the average US annual mileage (~13500mi/year):
    (13476/9697) * 2800kWh = ~3900kWh

    https://www.fhwa.dot.gov/ohim/onh00/bar8.htm

  11. gorr says:

    Probably owners of evs don’t do a lot of miles so it decrease cost per week compare to hot water but costs per miles are important.

    1. Mark.ca says:

      Stop bsing gorr, there are many ev owners that drive just like ice owners do. Go to Tesla CPO site and see how high mileage some of the cars have. Yes, cost/mile is important that’s why we drive evs!

    2. Bill Howland says:

      Well ‘price is no object’ $100,000 + Tesla drivers don’t really care what it costs to charge the car.

      Being of a frugal nature, I *DO* care how much it costs to charge my cars, – but the solar panels do it for free, at least as far as I’m concerned. Any annual excess I make I’m given 2 1/2 cents/kwh so I try to use as much Juice as I can, as long as I use it efficiently.

      But someone who MUST use an electric hot water tank and has or is thinking about solar panels, would be far better advised to install a Solar Water Heater system (Sunward, etc). since those systems are at least triple the efficiency of the water heater/solar panel combination, UNLESS they are in the southern US, and need to constantly cool the basement anyway…. Then, since they need to remove heat almost all seasons of the year, an expensive Hybrid water heater makes sense – of course in THAT case a direct solar water heater/hybrid electric makes THE MOST sense.

  12. David Cary says:

    One big issue with this is that the average car goes further than this and most households have 2 cars.

    Also – it has been discussed that the DOE numbers for hot water use have declined but haven’t been updated. Front loading washers, better dishwashers, flow restrictors etc.

    Our utility did a study and 3000 kwh was the average use. We are in NC so our water comes in a little warmer than some.

    Personally we drive 25k miles with a 3.5 kwh/mile average. Have solar hot water. Use dual fuel heat with a well insulated house. Car use is probably more like 35% of our use by first guess

  13. Anderlan says:

    Those EV numbers are for pretty low miles per year. That threatens to take away from the true message here:

    You have to drive more than 20,000 miles in a larger vehicle to use more energy for your EV than to heat your water.

  14. jim stack says:

    Just a minute. I have Solar HOT water and never use the back up electric which would be from my Solar PV.
    We also charge Off Peak when the power company has excess they used to dump. 70-90 Mega Watts every night.

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