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

SEP 13 2017 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

Categories: Charging

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48 Comments on "EV Charging Consumes Less Energy Than Water Heating In Typical US Home"

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Bar
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Bar

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

Brave Lil' Toaster
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Brave Lil' Toaster

Indeed! +1!

F150 Brian
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F150 Brian
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… Read more »
Bruno
Guest
Bruno

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

Djoni
Guest
Djoni

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.

Bruno
Guest
Bruno

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

Nick
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Nick

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.

Mint
Guest
Mint

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.

Pushmi-Pullyu
Guest
Pushmi-Pullyu
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.… Read more »
Just_Chris
Guest
Just_Chris
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… Read more »
John in AA
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John in AA

Thank you.

Mint
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Mint
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… Read more »
Tom
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Tom
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… Read more »
Pushmi-Pullyu
Guest
Pushmi-Pullyu
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,… Read more »
Oswald
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Oswald
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… Read more »
Mark.ca
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Mark.ca

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.

Bill Howland
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Bill Howland
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… Read more »
John Mausen
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John Mausen

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.

Get Real
Guest
Get Real

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

Mark.ca
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Mark.ca

Adults talking here…

GuyMan
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GuyMan

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

SparkEV
Guest

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.

Doggydogworld
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Doggydogworld

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.

Alaa
Guest
Alaa
+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… Read more »
David
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David

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

Alaa
Guest
Alaa
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… Read more »
mr. M
Guest
mr. M
“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… Read more »
Reply
Guest
Reply
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… Read more »
DJ
Guest
DJ

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.

Mark.ca
Guest
Mark.ca

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!

Asak
Guest
Asak

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.

Mark.ca
Guest
Mark.ca

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.

Alan
Guest
Alan
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… Read more »
Priusmaniac
Guest
Priusmaniac

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

Doggydogworld
Guest
Doggydogworld

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

Mark.ca
Guest
Mark.ca

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.

Kosh
Guest
Kosh

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)

ElectricAll
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ElectricAll

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.

Brave Lil' Toaster
Guest
Brave Lil' Toaster

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.

Kosh
Guest
Kosh

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.

Asak
Guest
Asak

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.

wavelet
Guest
wavelet

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

gorr
Guest
gorr

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.

Mark.ca
Guest
Mark.ca

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!

Bill Howland
Guest
Bill Howland
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… Read more »
David Cary
Guest
David Cary
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… Read more »
Anderlan
Guest
Anderlan

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.

jim stack
Guest
jim stack

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.