Many truck owners want to buy a camper shell to protect their gear. But gas is expensive. A big question everyone asks is: Will a truck canopy ruin my gas mileage (MPG)?
The short answer is: No, it won't ruin it. In fact, depending on how you drive, a canopy might actually help you save a little bit of gas.
Let's break down the simple science behind truck canopies and fuel economy.
1. The Wind: Why Open Truck Beds Are Bad for Gas
Have you ever run with an open umbrella behind you? It catches the wind and pulls you back. Your open truck bed does the exact same thing on the highway.
When you drive fast, the wind goes over the top of your cab and crashes right into your tailgate. This creates a "wind drag" (like a parachute) that makes your engine work harder to push the truck forward.
When you install a truck canopy, it changes the shape of your truck. The wind flows smoothly over the roof of the cab, along the top of the canopy, and slides off the back. This makes your truck cut through the air much easier.
(Note: If you are deciding between a truck canopy vs tonneau cover, both of them fix this wind problem!)
2. The Weight: Why Heavy Canopies Use More Gas
If a canopy makes the truck cut through the air better, why doesn't gas mileage double? The answer is weight.
Truck canopies are big. Depending on the material, they can be very heavy:
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Fiberglass canopies usually weigh around 150 to 200 pounds.
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Steel canopies (like our heavy-duty Armacap) weigh around 200 to 250 pounds.
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Aluminum canopies are lighter, but they can dent easily.
If you want to understand the exact differences in materials, check out our guide on the different types of truck canopies.
Extra weight means your truck is heavier. A heavier truck needs to burn more gas to start moving from a red light or a stop sign. If you are comparing steel vs aluminum truck canopies, remember that steel is heavier but much stronger for off-road trips.
3. Highway Driving vs. City Driving
So, who wins the battle between wind drag and heavy weight? It depends on where you drive.
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Highway Driving (You Win!): When you drive on the highway, you rarely stop. Weight doesn't matter as much. Wind drag is your biggest enemy. Because the canopy makes the wind slide off smoothly, most drivers notice a small improvement in gas mileage on long road trips (usually 1 to 2 MPG better).
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City Driving (You Lose a Little): In the city, you drive slowly. Wind drag doesn't matter at low speeds. But you are stopping at red lights and starting again constantly. The extra 200 pounds of the canopy will make your truck use slightly more gas.
The Final Verdict
Don't buy a truck canopy just to save gas money. The money you save on the highway won't be enough to pay for the cost of the cap. (Curious about prices? Read our 2026 guide on how much truck canopies cost).
However, you should not be afraid to buy a canopy either! The gas you lose in the city is balanced out by the gas you save on the highway. In the end, your overall MPG will stay almost exactly the same.
Buy a canopy because you want dry gear, a safe place for your tools, and an awesome setup for camping.
Frequently Asked Questions (FAQ)
Does a tonneau cover give better gas mileage than a canopy? They are very similar. Both stop the wind from hitting the tailgate. However, a tonneau cover is much lighter than a full canopy, so it might give you a tiny bit better MPG in the city.
Should I drive with my tailgate down to save gas? No! This is an old myth. Studies have proven that driving with the tailgate down actually makes wind drag worse and hurts your gas mileage. Keep it up, or get a bed cover.
Will a roof rack on top of my canopy hurt my MPG? Yes. Adding a roof rack, a rooftop tent, or big off-road gear on top of your canopy will catch the wind and drop your gas mileage by 1 to 3 MPG. Keep the roof clean when you aren't camping!