RVs that use the least fuel – First in a 3-part series

It’s no secret that we’re all frustrated by the price of fuel. One of the common threads in many social conversations is if people are actually planning to curtail their travels for the season because of the cost of a gallon of fuel.

In fact, many of you responded to a reader poll stating that you would make changes to your plans based on the price of fuel.

But we also know, based on the popularity of these daily RV reviews, that a lot of you are shopping for new RVs. So I thought I’d look at a few RVs that offer the lowest cost to operate from the standpoint of fuel economy. 

What affects fuel economy

There are a lot of things that affect how much fuel you use to travel a mile. While a common misconception is the number of cylinders an engine has, this number alone isn’t going to affect mileage much. 

Take, for example, a Ford F-150 with the EcoBoost^® six-cylinder engine. That engine sports 430 horsepower and 570 lb.-ft. of torque. That’s a lot of gusto. In fact, depending on which version of this engine is chosen, that’s more torque than the company’s new 7.3-liter gasoline V8—which is a huge V8. That V8 offers the same 430 horsepower but “only” 475 lb.-ft. of torque. 

So it’s not just cylinders, but a lot of factors. 

The air that you breathe

Essentially, an engine is nothing more than an air pump. The more air it can pump, the more power it has. This is a huge oversimplification, by the way. 

But another thing that radically affects fuel efficiency is how much power it takes to shove something through the air. If you look at the modern passenger car there is a legitimate complaint that “they all look alike.” There’s a reason for this. 

Cars are heavily regulated and one of the aspects of that regulation is fuel economy. The government has a fuel economy standard that carmakers need to achieve, so the cars are designed to use as little fuel as possible. Since shoving a car through the air is subject to the same dynamics as an RV, it makes sense that changing the shape of the RV to move more efficiently through the air would reduce the amount of fuel it takes to accomplish this. 

This is something that was recently studied by Airstream. It found that the shape of its trailers was less resistant to the forces of the wind than the typical square box that is your average travel trailer. 

Better mileage RVs

So, as promised, I’m going to look at RVs that are the most judicious with a gallon of fuel. I’m going to milk this, er, stretch this over several days. Today we’re going to start with motorized RVs. 

Essentially you’re going to see that there’s a very common theme here. Shoving a large box through the air is the least efficient way to move a rig, so the RV that takes the least amount of fuel to move is likely the one with a diesel engine, of course. 

But there are literally no Class A or Class C RVs on this list. Why? They’re gigantic boxes that are about as aerodynamic as your home. Maybe less so. 

These big square vehicles then add insult to injury by putting all sorts of things on the roof such as air conditioners, vent covers, satellite receivers and more. If your only factor in making a decision when buying an RV is fuel economy, then these are the ones to distance yourself from. 

Don’t feel badly. Travel trailers and fifth wheels, too, suffer the same fate. Well, except for the ones that we’ll mention tomorrow. 

The mileage maker

But the most efficient Class B RV I have reviewed, to my knowledge, is one that’s a favorite for a lot of reasons. That would be the Embassy RV Traveler, if you specifically get one based on the Mercedes-Benz Sprinter chassis. 

The reason for this is that you start with the already-efficient Mercedes-Benz 3.0-liter turbocharged diesel engine, and then don’t make as many profile-changing alterations to that shape. 

So the air conditioner in the Embassy RV Traveler is a different sort of unit that’s based loosely on the Toyota Prius AC system. It’s far more efficient but is also infinitely repairable, unlike all those Coleman units that are so popular. It’s also lower in profile—and that’s where you see the benefit. 

You can also get an Embassy RV in a Ram ProMaster^® wrapper; it is a gasoline V6 engine. While there are no federal requirements to provide fuel mileage ratings for larger-capacity trucks, it seems they’re getting about 17 miles per gallon on the highway. 

What I really like about this company is the innovative approach they’ve taken to the whole build process. Every aspect of the design and construction was looked at to optimize that process or system. 

Another leader

Another really solid Class B option is the VANaholic build. You can bring just about any van to Vanaholic and they’ll customize an interior based on their pieces to fit what you need. Not only does the company tailor their build to the van, but you could build one without a rooftop air conditioning system. That would eliminate the drag of one of those systems. 

Better yet, VANaholic uses an aluminum building system that provides a significantly lighter van than is typical with almost every other build. Yet this build methodology also results in a much stronger interior structure than wood would provide. 

While the assumption might be that reducing weight would increase fuel economy, this is less true in the circumstances where we drive our RVs. 

If our RVs were mostly confined to traffic and city life, then weight would be a bigger factor in their mileage. But since much of what we do is drive on the open road, it’s aerodynamics more than anything that can affect things. 

Still, there’s no harm in things being both lighter and stronger, and VANaholic doesn’t use any wood in their construction. Lighter and stronger is better, in case you’re keeping score. 

Another benefit of the whole bring-your-own-van model is the fact that you might be able to still find an older Mercedes-Benz Sprinter van with the five-cylinder diesel engine. Those were also marketed under the Dodge and Freightliner brands. 

Those things were really good at squeezing a mile from a gallon of diesel fuel and, bonus, they’re just simpler so more easily maintained. And, bigger bonus, no DEF.

Honorable mention

These smaller diesel rigs are actually pretty darned efficient, so you won’t see a huge difference in fuel mileage even with the rooftop air conditioners. 

So with that in mind, perhaps something more mainstream might be to your liking. I am quite a fan of several of the Class B RVs in the Winnebago family. The Winnebago Travato 59RL is based on the Ram ProMaster^® chassis. So you’ll have a gasoline engine, but this isn’t an inefficient package as far as motorhomes go. 

It’s also a rare example of a Class B that actually has a usable bathroom—and there’s a lot to be said for that. To be fair, the Embassy Traveler has a similar floor plan.

If you do choose to go diesel, then perhaps a Winnebago Revel 44E might suit you. Winnebago has done an unusual thing with the bed in the back by adding flares to where the rear-most side windows might otherwise be— so you get a bit of width. This isn’t significant enough to make a noticeable difference in the fuel economy of this rig, though. 

Since I’ve written that many RV companies just use the brochures from their competition as design inspiration, you could say the Jayco Terrain is a perfect example of that kind of thinking. Not that that’s necessarily a bad thing, but something to consider. 

In summary

We’ve got lots more options to look at in the mileage-maker department over the next couple of days, culminating with a look at the future and a look at the past. 

*****

I would love to read your comments and suggestions over on our new forums, where you can weigh in and start or join a discussion about all things RV. Here’s a link to my RV Reviews Forum.

Tony comes to RVtravel.com having worked at an RV dealership and been a lifelong RV enthusiast. He also has written the syndicated Curbside column about cars. You can find his writing here and at StressLessCamping where he also has a podcast about the RV life with his wife.

These RV reviews are written based on information provided by the manufacturers along with our writer’s own research. We receive no money or other financial benefits from these reviews. They are intended only as a brief overview of the vehicle, not a comprehensive critique, which would require a thorough inspection and/or test drive.

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