Understanding fuel consumption ratings

You bought a vehicle with fuel consumption ratings that fit your budget, but you’ve noticed that consumption is 10 to 20% higher than expected. You wonder if it’s a mistake, scam, or possibly excessive optimism on the part of the manufacturer.

In the United States, tests have always been performed under optimal conditions: new vehicle, minimum weight, low speed, and mild weather conditions (no wind, no exceptionally hot temperatures, etc.) While the tests have been refined over time, they’ve never been done in our Canadian winters or at high speeds, which could sometimes explain the significant disparity with reality. However, with some vehicles, you can almost reach the posted ratings on the highway if you drive very efficiently.

Starting in 2015, all vehicles sold must meet new standards, or 5-cycle testing, which replace the 2-cycle testing that was previously used. Fuel consumption tests now take into account accelerations, city driving, cold temperatures, use of air conditioning, and the presence of passengers. It is understandable that average consumption ratings will increase under these circumstances.

For example, a vehicle that had ratings of 7.9 and 5.9 L/100 km in 2014 now has ratings of 9.2 and 7.1 L/100 km, even though nothing has changed… except the testing method. That’s a difference of about $300 per year! Now when you’re buying a car, you’ll have some more realistic figures to help you drive more energy-efficiently.

All the same, even if you adjust your driving habits (accelerating slowly, braking less, driving the speed limit, etc.), the fact remains that the mechanical condition of your vehicle has a big impact on fuel consumption. Filters, lubricants, injectors, and wheel alignment can all cause consumption to increase or decrease depending on what condition they are in. Generally, when you invest in maintenance you’ll get back every dollar spent in fuel economy… and then some!

For information on fuel consumption ratings, visit the Natural Resources Canada website at