When people talk about car energy, they usually mean two things: how much energy a vehicle needs to move, and how much that energy costs you over time. As more drivers consider switching from gas to electric, understanding car energy isn’t just a nerdy side topic, it’s the basis for smarter buying decisions, especially in the used market.
Why car energy matters now
Energy is quickly becoming the biggest long‑term cost difference between gas and electric cars. The gap in efficiency between internal‑combustion engines and electric motors can easily mean hundreds of dollars per year for a typical driver, and much more for high‑mileage drivers.
What “car energy” actually means
At its core, car energy is the amount of fuel or electricity your vehicle needs to travel a certain distance. In a gas car, that’s gallons of gasoline or diesel. In an electric vehicle (EV), it’s kilowatt‑hours (kWh) of electricity. The less energy the car needs to go a mile, the more efficient, and cheaper to run, it is.
- Gasoline cars: energy stored as chemical energy in liquid fuel (gasoline or diesel).
- Hybrid cars: energy split between a gasoline engine and one or more electric motors.
- Battery electric vehicles (BEVs): energy stored as electricity in a high‑voltage battery pack.
Automakers and regulators convert this into familiar metrics so you can compare vehicles. For gas cars, you’ll see miles per gallon (MPG). For EVs, you’ll see things like miles per kilowatt‑hour (mi/kWh), kWh per 100 miles, and MPGe, a gasoline‑equivalent figure designed so you can compare an EV to a gas car on the same label.
Simple rule of thumb
Whether it’s MPG, MPGe, mi/kWh or kWh/100 miles, higher miles per unit of energy (or lower kWh/100 mi) almost always means lower running costs and lower emissions.
How gasoline cars turn fuel into motion
A gasoline car stores energy in the fuel tank. The engine burns that fuel to create hot, expanding gases, which push pistons, spin a crankshaft, go through the transmission and eventually turn the wheels. It’s a complex mechanical chain, and every step wastes some energy as heat or friction.
- Only about 20–30% of the chemical energy in gasoline actually moves the car down the road. The rest is lost as heat, noise and mechanical losses.
- Fuel economy for new gasoline cars in 2024 model year typically ranges from roughly 20–35 MPG for mainstream sedans and crossovers, with efficient hybrids in the 40–50 MPG range and trucks and performance vehicles well below that.
- Stop‑and‑go city driving tends to be less efficient than steady highway cruising for traditional gas cars, because the engine idles and wastes fuel whenever you’re not moving.
Why engines feel hot
That heat pouring off a gasoline engine or out of the exhaust isn’t a feature, it’s wasted energy you already paid for at the pump. From an energy standpoint, every degree of unnecessary heat is money and fuel literally evaporating into the air.
How electric cars use and save energy
Electric cars flip that script. Instead of burning fuel, they draw electricity from a battery pack and feed it to an electric motor. That motor converts electrical energy into motion with far fewer moving parts and much less waste.
- Modern EV drivetrains can turn 70–90% of the energy in the battery into motion at the wheels under many real‑world conditions, far better than combustion engines.
- For 2024 model‑year EVs in the U.S., official efficiency spans roughly 53–140 MPGe, with combined consumption from about 1.5 to 4.2 miles per kWh depending on size and shape.
- Regenerative braking lets an EV recapture some energy normally lost as heat in the brake pads, especially in city driving and stop‑and‑go traffic.
Why EVs feel so efficient
When you press the accelerator in an EV, most of the energy you just pulled from the grid goes directly into pushing the car forward. That’s why even heavy electric SUVs can post MPGe figures that would be impossible for similarly sized gas models.
MPG, MPGe and kWh per mile: making sense of the numbers
Because gas and electric cars use different kinds of energy, you’ll see different units on their window stickers. To really understand car energy, it helps to know how to translate between them.
Key ways we measure car energy
Same idea, different units depending on whether the car uses fuel or electricity.
Miles per gallon (MPG)
Used for: Gasoline and diesel vehicles.
Higher MPG means the car goes farther on each gallon of fuel. A 30 MPG car uses less energy (and money) per mile than a 20 MPG car.
Miles per kWh (mi/kWh)
Used for: Electric vehicles.
Higher mi/kWh is better. If one EV gets 4 mi/kWh and another gets 2.5, the first one uses much less energy per mile.
MPGe & kWh/100 miles
Used for: Comparing EVs to gas cars.
MPGe expresses EV efficiency as if electricity were gasoline. kWh/100 mi is the flip side: lower numbers mean less energy used.
The U.S. labels assume that 33.7 kWh of electricity equals the energy in one gallon of gasoline. That allows government agencies to publish MPGe figures that fall in a familiar MPG‑style range for shoppers.
How efficient are today’s cars?
How to compare two cars fairly
When you’re shopping, don’t just look at estimated range. Compare MPG or MPGe and kWh/100 miles. Range tells you how far you can go on a full tank or battery; efficiency tells you how much energy, and money, it takes to get there.
What really affects your car’s energy use
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No matter what you drive, several factors heavily influence how much car energy you use on a daily basis. Some are baked into the vehicle’s design; others are entirely under your control.
Four big levers that change car energy use
You can’t change physics, but you can choose vehicles and habits that work with it.
Size, weight & aerodynamics
Large SUVs and trucks push more air and weigh more, so they almost always use more energy per mile than compact cars, whether they’re gas or electric.
Smooth shapes (like many EV sedans) cut through the air more easily, improving efficiency at highway speeds.
Speed & driving style
Energy use climbs quickly above about 60–65 mph. Aggressive acceleration and hard braking waste energy in both gas and electric cars.
EVs soften the blow with regenerative braking, but gentle driving still wins.
Weather & climate control
Cold weather thickens fluids in gas cars and reduces battery performance in EVs. Heating and A/C draw extra energy in both.
Pre‑conditioning an EV while plugged in can warm or cool the cabin without cutting into your battery as much.
Maintenance & tires
Under‑inflated tires, misaligned wheels, clogged air filters (for gas cars) and worn components all increase drag and energy use.
Low‑rolling‑resistance tires and regular service can meaningfully reduce energy consumption over time.
Don’t ignore tire pressure
Running even 5–10 psi below the recommended tire pressure can noticeably increase the energy your car needs to move, and it can reduce tire life and safety at the same time.
Real‑world car energy examples: gas vs EV
To make car energy more concrete, let’s put a typical American driving pattern, about 12,000 miles per year, into simple, real‑world comparisons. We’ll look at one mainstream gasoline car, one efficient hybrid and one typical EV.
Estimated annual energy use for three types of cars
Simple, rounded examples to show how different drivetrains turn energy into real‑world usage over 12,000 miles.
| Vehicle type & example | Efficiency metric | Energy needed for 12,000 miles | What that means in practice |
|---|---|---|---|
| Gas sedan (~30 MPG) | 30 miles per gallon | ~400 gallons of gasoline | A common compact or midsize sedan. At $3.50 per gallon, that’s about $1,400/year in fuel. |
| Hybrid (~50 MPG) | 50 miles per gallon | ~240 gallons of gasoline | A modern hybrid can cut fuel use by roughly 40% versus the 30 MPG car, saving hundreds per year. |
| Mainstream EV (~3.3 mi/kWh) | 3.3 miles per kWh (~30 kWh/100 mi) | ~3,640 kWh of electricity | At $0.15 per kWh, that’s about $550/year in energy. Even at higher rates, EVs often undercut gas on total energy cost. |
Actual numbers vary by model and driving style, but the pattern, EVs using far less energy per mile, holds across the market.
The takeaway isn’t that every EV is cheap to run or every gas car is expensive. A heavy electric pickup can use more energy per mile than a compact gas hatchback. But, comparing like‑for‑like vehicles (compact vs compact, SUV vs SUV), EVs typically need much less energy to cover the same distance.
Used EVs and long‑term car energy costs
When you’re considering a used car, car energy becomes a long‑term cost question: how much will this vehicle cost to keep moving over the next five to ten years? That’s where used EVs can shine, if you understand battery health and charging.
- Because EV drivetrains are more efficient and electricity is often cheaper per unit of energy than gasoline, used EVs can dramatically cut your ongoing energy spend compared with similar used gas cars.
- Battery health matters: as batteries age and degrade, usable capacity drops, which can modestly affect range and, in some cases, efficiency. A healthy battery is key to getting the most from your car’s energy.
- Charging access shapes your costs. Home charging at off‑peak rates is usually the cheapest way to power an EV. Relying mostly on DC fast charging can be both more expensive and harder on the battery over time.
How Recharged helps with the energy math
Every EV sold through Recharged includes a Recharged Score Report with verified battery health and pricing benchmarks. That makes it easier to estimate your future energy costs and compare a used EV’s total cost of ownership to a similar gas model.
Practical ways to cut your car energy use today
Whether you’re driving a gasoline vehicle today or you’ve already moved into an EV, there are concrete steps you can take this week to use less car energy and spend less money going the same distance.
Eight concrete steps to save car energy
1. Slow down a little on the highway
Aerodynamic drag rises quickly with speed. Dropping from 75 to 65 mph can meaningfully reduce fuel or electricity use without adding much time to most trips.
2. Accelerate and brake smoothly
Hard launches and late, heavy braking waste energy. In EVs, smoother driving also lets regenerative braking recover more energy instead of turning it into heat.
3. Keep your tires properly inflated
Check pressures at least monthly. Proper inflation can improve efficiency, extend tire life and improve safety, all for the price of a few minutes and a tire gauge.
4. Trim unnecessary weight and roof racks
Remove rarely used cargo boxes, bike racks and heavy gear from the car. Extra mass and drag are silent energy drains at every speed.
5. Use eco modes and scheduling
Most modern cars include ECO or efficiency modes. In EVs, schedule charging and cabin pre‑conditioning so the car draws power from the grid while plugged in, not from the battery once you’re driving.
6. Plan charging and fueling smartly
For EVs, favor home or workplace charging when electricity is cheaper. For gas cars, avoid unnecessary detours and idling in long drive‑through lines that burn fuel without moving you forward.
7. Keep up with maintenance
Alignments, oil changes (for gas cars), fresh filters and proper coolant levels all help reduce energy losses. Neglect usually shows up as higher fuel or electricity use.
8. Match the car to your real needs
If you rarely tow or haul, you may not need a large truck or three‑row SUV. A smaller, more efficient used EV or hybrid can cover daily miles with far less energy and cost.
Thinking about a switch to a used EV?
If you’re ready to turn lower car energy use into real savings, a quality used EV can be a smart step. Recharged offers EV‑specialist support, nationwide delivery, and transparent Recharged Score battery diagnostics so you can compare options with confidence.
Car energy FAQ
Frequently asked questions about car energy
Key takeaways on car energy
If you strip away the jargon, car energy is about how efficiently a vehicle turns stored energy, gasoline or electricity, into motion, and how much that costs you every year. Modern EVs typically use far less energy per mile than comparable gas cars, and that difference adds up quickly over tens of thousands of miles.
At the same time, not all vehicles are created equal. Size, weight, aerodynamics, weather and driving style can swing energy use dramatically for both gas and electric models. By understanding metrics like MPG, MPGe, mi/kWh and kWh/100 miles, and by looking closely at battery health on used EVs, you can make decisions that align with both your budget and your values.
If a used EV is on your radar, Recharged is built to make that process simpler. With transparent Recharged Scores, EV‑savvy support and nationwide delivery, you can focus on what really matters: choosing the car with the right energy profile for your daily life, and keeping more of your own energy (and money) for the drives that matter most.
