How Much Does a Roof Rack Really Affect Your Car’s Fuel Efficiency?
You’ve probably seen those sleek roof racks zipping down the highway, loaded with bikes, kayaks, or suitcases. They’re a lifesaver for family road trips and outdoor adventures. But here’s a question that doesn’t get asked enough: what’s the real cost of all that extra storage? Not just the price tag, but the impact on your wallet every time you fill up at the pump.
Why Does a Roof Rack Increase Gas Consumption?
It all comes down to aerodynamics. Your car is designed to slice through the air as efficiently as possible. Add a roof rack—even an empty one—and you’re suddenly dealing with extra drag. Think of it like running with a parachute behind you. The engine has to work harder to push your car forward, which means burning more fuel.
A 2016 study from the National Renewable Energy Laboratory found that an empty roof rack can reduce fuel economy by about 1 percent. Load it up with cargo, and that number jumps—sometimes by as much as 25 percent, depending on your speed and the size of your load. At highway speeds, the effect is even more pronounced. That’s because wind resistance increases exponentially the faster you go.
How Much Could That Extra Drag Cost You Over Time?
Let’s put some real numbers to it. Say your car averages 30 miles per gallon on the highway. With a fully loaded roof rack, you might see that number drop to 22 or even 20 mpg. Over a 500-mile road trip, that’s an extra 3 to 5 gallons of gas—easily $15 to $25 more per trip at current prices. Multiply that by a few trips a year, and you’re looking at a noticeable dent in your travel budget.
And it’s not just long hauls. Even short commutes add up. According to the U.S. Department of Energy, roof racks and carriers collectively cost American drivers hundreds of millions of gallons of gasoline each year. That’s a lot of money—and a lot of unnecessary emissions.
Are All Roof Racks Created Equal?
Not quite. The design and placement of your roof rack matter. Low-profile, aerodynamic racks create less drag than bulky, square ones. Cargo boxes are generally better than open baskets, since they’re designed to cut through the wind. Still, even the best-designed rack will have some impact.
It’s also worth noting that some vehicles are more affected than others. Smaller cars and hybrids, which rely on streamlined shapes for efficiency, tend to lose more mpg than larger SUVs or trucks. But nobody’s immune.
What Can You Do to Minimize the Impact?
Here’s the good news: you don’t have to ditch your roof rack altogether. A few simple tweaks can make a big difference.
First, remove the rack when you’re not using it. It sounds obvious, but many drivers leave them on year-round out of convenience. If you only need the rack for occasional trips, taking it off can save you real money over time.
Second, pack smart. Keep loads as low and as streamlined as possible. Avoid stacking items high or letting them stick out into the wind. If you’re carrying bikes or skis, consider rear-mounted options—they tend to create less drag.
Finally, slow down a bit. Even dropping your speed by 5 mph on the highway can help offset the extra fuel burn from a loaded roof rack.
Is There a Greener Way to Haul Your Gear?
If you’re looking to reduce your carbon footprint, consider alternatives. Hitch-mounted carriers and trailers often have less impact on aerodynamics than roof racks. Some electric vehicles offer built-in storage solutions that don’t compromise efficiency as much. And if you’re just carrying a few extra bags, a spacious trunk or back seat might do the trick.
The big takeaway? Roof racks aren’t about perfection—they’re about smarter adjustments. Start with one change this week, and you’ll likely spot the difference by month’s end.
