Gas-Saving Claims

When gas prices climb, products that claim they’ll save gas might look good. But it's a smart idea to be skeptical of any gas-saving claims for automotive devices or oil and gas additives.

Here are some examples of claims you might see:

"Improves fuel economy by 20 percent."

Ads typically tout savings from 12 to 25 percent. However, despite evaluating or testing more than 100 alleged gas-saving devices, the Environmental Protection Agency (EPA) has not found any product that significantly improves gas mileage. In fact, some "gas-saving" products may damage a car's engine or substantially increase exhaust emissions.

"After installing this product, my car gets an extra 4 miles per gallon."

Ads may feature glowing testimonials from satisfied customers. But few people have the ability or the equipment to test for precise changes in gas mileage after installing a product that claims to save gas. Many variables affect fuel consumption, including traffic, road and weather conditions, and the car's condition.

For example, a letter to a company praised its "gas-saving" product. But the product was installed at the same time the car owner got a complete engine tune-up — a fact not mentioned in the letter. The bump in gas mileage attributed to the product may well have been the result of the tune-up.

"It’s approved by the federal government."

No government agency endorses gas-saving products for cars. The most an ad could claim is that EPA has reached certain conclusions about possible gas savings by testing the product or by evaluating the manufacturer's own test data. If the seller claims that its product has been evaluated by EPA, ask for a copy of the EPA report, or check epa.gov for information.

The Effect on Your Car

While EPA evaluates or tests some products to determine whether they’ll significantly improve or hurt fuel economy, the agency doesn’t conduct durability tests: it can’t say what effect the products will have on a vehicle over time. It's possible that some products may harm the car or negatively affect its performance. In fact, the emission control systems in today's cars are very sophisticated and complex with features that alert drivers to problems. Retrofit products may have a negative effect on these systems.

Real Money-Saving Steps

You can take many free or low-cost steps to save on gas, including buying only the octane level you need, watching your speed, properly maintaining the vehicle, and checking tire pressure. For more tips, read Saving Money on Gas.

If you’re in the market for a car, you also might consider getting one that’s fuel-efficient. In fact, deciding which vehicle to buy may be the most important fuel economy choice you make. The difference between a car that gets 20 MPG (miles per gallon) and one that gets 30 MPG amounts to $4,375 over 5 years, assuming gas costs $3.50 per gallon and you drive 15,000 miles a year. 

Visit fueleconomy.gov for gas mileage estimates and other information for cars dating from 1985.

Devices Tested by EPA

In the past, EPA tested many types of "gas-saving" products as part of its Voluntary Aftermarket Retrofit Device Evaluation Program. Most devices tested had little to no effect on fuel economy or exhaust emissions; some even had a negative effect. For the specific products’ test results, visit EPA's website.

EPA testing also has received no credible data showing a positive effect on fuel economy from:

• devices that turn water into fuel
• fuel line devices
• mixture enhancers

For more from EPA, read Devices and Additives to Improve Fuel Economy and Reduce Pollution — Do They Really Work?

What Now?

If you're not satisfied with a product that claims to save gas, contact the manufacturer and ask for a refund. Most companies offer money-back guarantees. Contact the company, even if the guarantee period has expired.

If you're not satisfied with the company's response, contact your local consumer protection agency. You also can file a complaint with the FTC.