You’re Probably Wasting a Ton of Money on Premium Gas. Here’s Why

If you use premium fuel in your gas tank, you might be one of 16.5 million Americans wasting your money, according a recent study by AAA.

The study confirmed what auto experts, apparently, have known for years that consumers are getting wrong: “Premium” isn’t higher-quality fuel, and your car probably doesn’t need it.

Then why did U.S. drivers waste, as AAA calculated, $2.1 billion dollars on unnecessary premium-grade gasoline last year?

The Myth of Premium Fuel

Many of us see three options at the pump and assume each higher-priced product is better than the last.

You may, like my dad has advised my sister and me, choose premium-grade, expecting to get better fuel economy, cleaner emissions and an overall better life for your engine.

Unfortunately, you’d be wrong, and it could cost you — and your unsuspecting daughters — almost $300 each year.

Premium costs an average 50 cents more per gallon than regular, CNN reports, and the average U.S. driver uses 583 gallons per year.

Normally I would take my dad on his word regarding basic vehicle maintenance, because that’s what dads are for. In this case, though, he’s probably acting on an enduring myth.

AAA’s recent evaluation measured vehicle performance, fuel economy and emissions using both regular-grade and premium-grade fuel.

“AAA’s tests reveal that there is no benefit to using premium gasoline in a vehicle that requires regular fuel,” said Megan McKernan, manager of the Automobile Club of Southern California’s Automotive Research Center, which partnered with AAA on the research.

“Premium gasoline is specifically formulated to be compatible with specific types of engine designs, and most vehicles cannot take advantage of the higher octane rating.”

What is Premium Gasoline, and Does My Car Need It?

“Premium,” in the case of gasoline, means a higher octane rating — not higher quality.

High-octane fuel can support better horsepower in high-performance cars, TPH assistant editor and former automotive mechanic/technical writer Justin Cupler explained to me.

And, in case you’re wondering, as I was, what horsepower actually means, Cupler (patiently) explained, “Horsepower is basically how fast the car is.”

Higher horsepower, in a nutshell, means your car will take off and get up to speed faster than a car with lower horsepower. It will also make your vehicle better for towing and in situations that require extra power, like climbing mountain roads.

Most likely, your vehicle is among the majority designed to run on regular fuel, and using premium can’t improve its performance.

Using premium fuel in a standard vehicle is kind of like taking a supplement with 300% of your daily value of Vitamin C. You don’t get three times the benefits; the extra is just flushed through your body unnoticed.

If You Drive a High-Performance Vehicle

If you drive a high-performance or luxury vehicle the manufacturer designed to take advantage of higher-octane fuel, you probably know it because you likely selected for that powerful engine.

Even many high-performance vehicles only recommend premium fuel, says Cupler, and that’s to ensure performance, not the safety or health of your vehicle.

For example, the 2017 Mazda CX-9 is equipped with a 2.5-liter turbocharged engine. It will run fine on regular (87 octane) fuel, but the engine’s electronic systems limit it to only 227 horsepower.

With premium (93 octane) in the tank, the engine can reach its maximum output of 250 horsepower (translation: faster).

Using regular fuel in a premium-recommended vehicle won’t cause damage or affect performance long term, because your car’s computer recognizes the potential engine knock caused by low-octane fuel and adjusts its ignition accordingly. This ignition adjustment is what often leads to the reduced horsepower output of the engine.

I could delve more into my newfound knowledge of automotive science, but I suspect you’re not as much of a nerd as I am. You’re just wondering WTF you’re supposed to do with this information.

Bottom line: Check your owner’s manual.

“When it comes to gasoline, ‘premium’ does not mean ‘better’ if your vehicle doesn’t require it,” John Nielsen, AAA’s managing director of Automotive Engineering and Repair, said in a press release this week.

Check the manual for your vehicle’s recommendations:

• If it doesn’t recommend premium or list a higher horsepower with the higher-octane fuel, you won’t get any benefit from paying more for premium.

• If it recommends premium, you’ll probably sacrifice performance if you fill up with regular.

• If the manual says premium is “required,” you should fork over the extra cash at least most of the time.

Occasionally using regular gas in a premium-required vehicle — if you’re low on funds this week, for example — won’t be a problem, Cupler explains. But over time, especially in older vehicles, it could cause engine knock that may result in damage over time.

If you hear that knocking, add premium fuel to your tank as soon as possible, Greg Brannon, AAA’s head of Automotive Engineering recommended to CNN.

New vehicles that list premium fuel as a requirement pose a different issue altogether. While they will likely run just fine with lower-octane fuel, you could end up with a voided warranty for picking the wrong fuel at the pump.

Only 16% of U.S. drivers currently own a vehicle that requires premium fuel, according to AAA.

Why Does My Dad Think Premium Is Better?

So why did my dad, who is not a gearhead by any stretch of the imagination and has never owned a high-performance vehicle, tell me premium gasoline would be better for the 1980-something Buick LeSabre sedan I drove in high school?

Turns out, “premium” used to, in fact, mean “better” gasoline.

Before they became required and regulated in 1997, detergents and other additives that keep engine innards and emissions clean were only in premium fuel. When that was the case, springing for premium meant keeping your engine cleaner and your carbon footprint smaller.

Not anymore.

Now all our gas includes these additives by law. Octane level is the only remaining difference between regular and premium fuel.

Quality might vary by brand — not by grade —  but all the fuel you get at any gas station has to meet basic modern requirements.

So, thank you, Dad, but I guess this is one opportunity to learn from the younger generation — and save a few bucks every time you fill up.

Your Turn: Have you been wasting money on premium gasoline?

Dana Sitar (@danasitar) is a staff writer at The Penny Hoarder. She’s written for Huffington Post, Entrepreneur.com, Writer’s Digest and more, attempting humor wherever it’s allowed (and sometimes where it’s not).