As EVs become more and more popular, there’s one specification that hasn’t seemed to leave buyers' minds: range. Understandably, buyers want to have an idea of what the actual range is on an EV before they buy it. EVs have had range be one of the original specs that differentiated them from each other when EVs first became attainable (think the first gen Nissan Leaf and the original Model S.) Unfortunately, range is a hard number to quantify in a way that can be reproducible for everyone. As you may know, range can be easily affected by a variety of factors, from the way a driver uses their vehicle, to the tires equipped on the vehicle, to the ambient temperature, to the geography of the roads they’re being driven on. Because of this, the listed range for EVs should be looked at as a middle ground: not the highest range possible but also not the minimum. Because of the energy density discrepancy between gasoline and lithium ion batteries, the numbers fluctuate in a much more noticeable way in an EV versus a gas powered vehicle. This is why there’s a better number for consumers to be evaluating when they’re looking to purchase an EV: efficiency.

Unlike range, which just tries to approximate the distance to travel on a battery, efficiency actually tries to quantify how effectively it uses stored energy from the battery. This factors in charging losses, which helps deliver a better expectation for consumers. Think about it: gas cars are rated for their efficiency, which ultimately affects how much consumers will pay at the pump for the fuel to keep the car running. EV efficiency, usually measured in watt hours per mile (Wh/mi), attempts to do the same thing. It’s important to remember that energy stored in gasoline and batteries is fundamentally different: The mass-based energy density of batteries is in the range of 0.1 to 0.27 kWh/kg, while gasoline is 13 kWh/kg. While the engine in an ICE vehicle burns most of the energy available in gas away as heat, EVs convert nearly 90% of it to mechanical energy. Therefore, the efficiency difference between the fuel types is even more impressive.

As a general rule, the higher the efficiency of any vehicle (again, how effectively it uses its stored energy) directly affects how much the vehicle will cost to run. So for consumers, it’s much more beneficial to use a unit of measure that can help them understand how much they could save by switching to that particular vehicle. Unlike efficiency, range being higher doesn’t always mean better (or cheaper.) A Lucid Air with the largest battery pack can go over 500 miles on a charge. While that number is great on paper, the reality is that the average driver will never need that much range on a daily basis. Because of this, the battery and car end up being very heavy, which impacts efficiency and doesn’t necessarily help the owner in the long run, especially as high speed charging continues to proliferate throughout the country.

So next time range is brought into the conversation about EVs be sure to mention that it’s efficiency, not range, that has a greater impact on the daily use of an EV.