The Cost of Adventure: How Poor RV Gas Mileage Can Break Your Vacation Budget

Planning a road trip in an RV is exciting. Thinking about the adventures ahead can become all-consuming. But before you hit the road, it’s worth considering how the average rv gas mileage will impact your fuel budget. RV’s are not known for efficiency and can be very costly to operate.  

Let’s take a look at what affects RV miles per gallon (MPG) and how you can improve yours!

What Is the Average MPG on an RV?

The average MPG on an RV varies significantly from class to class and varies anywhere from 6 to 30 MPG. For example, a 19-foot Class B campervan will get much better gas mileage than a 40-foot Class A motorhome. The weight and shape difference also means more drag and resistance. So let’s look at the MPG of drivable RVs and towable RVs.

Motorhome Average MPG

Class Bs will get the best gas mileage out of any type of RV because it’s the smallest and lightest. It’s similar to driving a cargo van. Although they can vary from model to model, a Class B generally gets anywhere from 16 to 25 MPG. Diesel rigs tend to get the best fuel economy, and some of the B+ Ducato chassis rigs we have rented got between 23 and 27 MPG.

On the other hand, Class As have the worst fuel efficiency, averaging between 6 to 12 MPG. Our 45-foot 14-liter diesel motorhome averages around 7.5MPG for us but can vary significantly depending on driving conditions.

Class C motorhomes are somewhere in the middle, with an average between 10 to 18 MPG.

RV Trailer Average MPG 

First, the MPG will vary greatly based on the type of tow vehicle. If you tow a small teardrop trailer that weighs 3,000 pounds with a Ford Explorer, you might get up to 20 MPG. 

However, if you tow a 37-foot fifth wheel that weighs 12,000 pounds with a Chevrolet Silverado 2500, you might only get about 11 MPG. So the tow vehicle, in addition to the length and weight of the RV, will significantly affect the fuel efficiency.

We towed a 35-foot 17,000-pound fifth wheel with a Dodge Ram 3500 (2WD) truck for almost 100k miles and averaged 11 MPG. Like with motorhomes, diesel trucks tend to get much better fuel economy towing compared to gas alternatives.

RV MPG Factors

Besides the overall size of the RV and its weight, there are other factors that affect the MPG. The most significant factor is speed. Once you get up to 60 MPH, the fuel efficiency usually starts to decrease rapidly. This is why it’s suggested to stay around 60 to 65 MPH when driving a motorhome or towing a trailer. The reason for this is that the surface area of a motorhome is so large and wind resistance increases exponentially at these operational speeds.

In addition, the engine type – gas or diesel – affects fuel efficiency. Diesel engines tend to get better fuel economy. Diesel fuel has high energy density and compression ratios, leading to better combustion and fuel economy. So if you drive a diesel motorhome or tow vehicle, you tend to get 30-40% better fuel economy. Diesel engines also produce higher torque which is required to move large masses. This torque allows the engines to operate at lower speeds when hauling and can further improve MPG over a gas engine for towing or hauling.

Just like with standard vehicles, the aerodynamics, tire pressure, and driving technique also influence the RV gas mileage. Airstreams are designed to glide down the road. This is why you don’t see many square, boxy-type RVs anymore. Driving with low tire pressure means your tires are soft, and there’s more resistance between the road and the rubber. Your engine will have to work harder.

Finally, if you’re weaving in and out of traffic, speeding up and slowing down often, your driving technique will reduce your MPG. You want to maintain a steady speed to increase fuel efficiency, which is why interstate driving is ideal for RVers.

Did you know? There are several states that don’t trust you to pump your own gas!

What Speed Is Most Efficient for RV Gas Mileage?

As mentioned earlier, speed has the largest effect on fuel economy. The faster you go, the more fuel you waste on wind resistance. Vehicles are designed to be efficient at particular speeds, and it may depend on where your vehicle shifts into its highest gear. For many, this is 55 mph and yields good fuel economy. However, if you are willing to drive even slower, most RVs top out fuel economy of around 30-40 mph.

You may be surprised to learn that these speeds and fuel economy are true for many cars as well. Cars, however, have a much smaller surface area, and the higher speeds have a far lower drag-to-power ratio.

Does Cruise Control Use More Gas?

Most of the time, cruise control doesn’t use more fuel. Instead, it helps keep your vehicle at the same speed, increasing fuel efficiency. It’s particularly useful on level terrain; however, in the hills and mountains, cruise control may decrease your fuel economy.

We don’t recommend using cruise control in rolling hills because it tends to over-accelerate up the hills. Many times you can anticipate a hill speed up, then let the momentum slow you down a bit while you climb it. This tends to be far more fuel efficient than shifting hard and accelerating.

If, however, you are climbing a steep, very long grade, we recommend slowing down to a speed your RV can safely climb at and setting cruise until you make it to the top.

Pro Tip: Take a closer look at how cruise control can help save you gas.

What Are the Best Ways to Save on RV Gas?

We’ve already mentioned a few factors influencing the RV MPG on the highway. Here are some other tips for getting the most out of your visit to the fuel pump.

Reduce Weight in Your RV

Heavier RVs decrease fuel economy. This is why Class A motorhomes have half of the RV MPG of a Class B campervan. If you can reduce the weight in your RV, you’ll improve performance on the road. This is worth considering when purchasing a new or used RV.

Check Your Tire Pressure

As already mentioned, you don’t want to have low tire pressure. Not only does it decrease fuel economy, but it also raises the risk of a tire blowout. Always check your tire pressure before every trip when the tires are cold. You’ll find the recommended PSI on the tire sidewall.

Pro Tip: Make measuring your tire pressure quick and easy by using one of these Best RV Tire Pressure Monitoring Systems.

Avoid Driving in High Winds

There are multiple reasons why you should avoid driving in high winds. Increased sway and lack of control can lead to dangerous consequences. In addition, a head or side wind can essentially increase the speed you are traveling, as apparent to your engine. If you are driving 60 mph with a 20 mph headwind, your engine feels like it’s trying to drive 80 mph.

We have seen our fuel economy increase (with a tailwind) or decrease (with a headwind) by as much as 50% because of wind conditions. Because of this, we try to be flexible and watch the weather for our routes. Check out a day early, stay a day later, or wait a few hours before hitting the road if the winds are bad.

Maintain a Steady Speed

We’ve already talked about this, but it’s worth repeating. Speeding up to pass a few cars and then slowing down because you’ve reached an unsafe speed and then speeding up to pass a few cars again only harms your fuel economy. 

Use cruise control or pay attention to your speed to maintain a steady speed down the highway, improving your RV MPG.

Avoid Excessive Idling 

Vehicles get 0 MPG when idling. So your RV gas mileage will decrease the longer you stay put. It can also cause greater engine wear over time, leading to later maintenance costs.

Camp Closer to Home

To save fuel, consider camping closer to home. By traveling fewer miles, you’ll be able to enjoy camping more often without having to visit the pump. This may be a no-brainer, but it costs more to travel farther.

Use Fuel Memberships for Discounts at the Pump

Finally, check into fuel memberships for discounts at the pump. Diesel drivers can sign up for TSD Open Roads, which can save hundreds of dollars a year on diesel fuel at select travel centers and truck stops. 

GasBuddy will help you find the cheapest gas around, and other apps for individual fuel stations like Shell or BP have their own rewards programs.

Pro Tip: Unfortunately, some RVers are maxing out their budgets with $1,000 Fuel Fill-Ups. Find out if this could be a reality for you!

Is a Gas or Diesel RV More Cost Effective?  

Diesel RVs and trucks are more expensive upfront. The fuel is more usually expensive than gasoline as well. In general, diesel gets about 30% better fuel economy. Most of the time, when we have done the math, it becomes a wash. However, the diesel engine usually provides a better driving experience with a heavy vehicle.

The savings could add up depending on how many miles you’re putting on your RV or truck each year, so it’s important to do the math and decide which is right for you.

Improve Your Gas Mileage to RV Longer

When you invest in an RV, you’re committing to the camping lifestyle. You’ve spent way too much money, even for an entry-level travel trailer, to spend more on fuel. If you can adopt these driving techniques and apply the tips mentioned to save fuel, you’ll be a safer driver and a happier camper.

Have you found any other ways to increase your RV MPG while traveling? Tell us your tips in the comments!

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