The words recreational vehicle (RV) and fuel efficiency don’t necessarily go hand-in-hand, or even belong in the same sentence. But when fuel prices are $4 per gallon, RV owners inevitably begin exploring ways to boost their miles per gallon (mpg). Realistically, there is no way to reengineer the capabilities of an RV. However, there are a handful of ways you can maximize your mileage. From driving style, technique, and conditions to overall aerodynamics, most RV owners find that there is plenty of room for improvement in maximizing their RV fuel economy department. Combine that with high-quality fuel, reputable fuel additives, and proper vehicle maintenance and the number of miles covered between fill-ups can increase substantially. Here’s how you do it.
What Kind Of Mileage To Expect
From the outset, it’s important to know what type of mileage to expect from your RV. With Class A RV’s (motorhomes), 6 to 10-mpg is the norm, while Class B versions (camper vans) typically see 15-22 mpg and Class C RV’s (medium size motorhomes) usually return anywhere from 9 to 16-mpg. As for conventional, bumper tow travel trailers, much depends on the tow vehicle and the length and weight of the trailer, but 8-15 mpg is typical, while fifth-wheel campers tend to drop the tow vehicle’s fuel economy down to 8-13 mpg. In all of the above scenarios, the RV’s (or tow rig’s) use of a diesel or gasoline power plant makes a big difference, the former form of internal combustion enjoying 30 to 40-percent better fuel economy, on average.
GVWR And Aerodynamics
Your RV’s gross vehicle weight rating (GVWR) and wind resistance are the biggest factors in fuel economy, other than the type of engine, transmission, and gearing you have. Getting the overall curb weight of the RV, plus your cargo and passengers up and moving is part of the powertrain’s workload and, should you be loaded at GVWR, will make the commercial engine work that much harder. Additionally, most RV’s are wide and tall—not a good
combination for cutting through the wind. However, investing in aerodynamic improvements such as skirting, low rolling resistance tires, vented mud flaps, wheel covers, and trailer undertrays or bogie fairings can help increase mpg. Any minimization of wind resistance or lightening up the RV will serve to improve fuel economy.
Vehicle Speed Vs. Engine Speed
Knowing that one of the biggest variables in fuel mileage is wind resistance, it goes without
saying that faster cruising speeds will be detrimental to mpg. By simply slowing down your cruising speed on the highway, you can add considerable range to the equation. As a general rule of thumb for diesel-powered RV’s, keep your cruising speed at or near the rpm where your engine creates its peak torque rating. Take a motorhome with an 8.3L Cummins turning out 360 hp and 1,050 lb-ft for example. If peak torque comes online at 1,400 rpm, keeping your top-gear mph at or near that engine speed will likely yield the best mileage.
Driving Style
There is no room for aggressive acceleration in an RV owner’s quest to maximize his or her miles per gallon. However, maximizing fuel economy goes far beyond taking it easy on the go pedal. Stop-and-go driving in heavy traffic will drop mileage significantly, as can idling for extended periods of time. Reduced idle time is always highly recommended when every gallon counts. Cardinal rule: don’t forget that 0 mph is always 0 mpg. Maintaining consistent vehicle speeds, and speeds that are in close proximity with the speed limit, typically yield the best fuel consumption results.
Driving Conditions
The roads, elevation levels, and ambient temperatures you encounter along your journey can be detrimental to your RV’s mileage. When possible, avoid rough roads and high 
traffic areas (today’s real-time driving apps are great for navigating around stopped traffic or construction zones). In mountainous and hilly terrain, fuel economy always takes a hit. Think about it, thinner air makes the turbo work that much harder to fill the engine’s lungs, which requires more boost, as well as additional fuel to match that boost. Travel in freezing temperatures also takes its toll on fuel consumption, as winter diesel blends—thanks to an additive package that drops their cold filter plugging point (CFPP)—are less energy dense than summer blends.
Curb Your Use Of Accessories (And Appliances) While Driving
If so equipped, limiting the use of your RV’s onboard generator while driving can enhance its gas mileage. Most onboard generators consume fuel from the same tank that feeds the
engine. Cutting back on the use of cooking appliances, electronic devices, or anything else that consumes the RV’s fuel will provide an uptick in mpg. Though marginal, a generator that consumes ½-gallon to 1-gallon of fuel per hour (the case with most RV generators), can add up over the course of a long trip. Of course, choosing dashboard-mounted air conditioning over generator-powered, roof-mounted A/C units in a lengthy coach may not be the most comfortable choice on a route that passes through the desert…
Choose High Quality Fuel
Even having the chance of achieving optimum fuel economy starts with the fuel you put in 
your RV’s tank. Believe it or not, more than 95-percent of all fuel system issues originate in the fuel tank, and diesel fuel in particular can begin to breakdown in as little as four weeks after being produced. This is why it’s so important to fill up (and top off) at high-traffic, highly-used fuel stations that see quick fuel turnover rates—to get the freshest fuel possible. Low-traffic filling stations are often plagued with water-laced diesel fuel, thanks to diesel being highly attracted to H2O at the molecular level.
Add A Proven Fuel Additive To The Tank
To combat low-energy, winter-blend fuel, ultra low sulfur diesel’s (ULSD’s) inherent lack of lubricity, and to keep the overall cleanliness of the fuel system on the up-and-up, treat
your RV to a reputable fuel additive (or two). Ideally, a product that improves diesel fuel’s lubricity properties (for component longevity), increases its cetane level (for increased energy and a more efficient burn) and that cleanses the fuel system of internal deposits (for optimum operational efficiency) should get the nod. A first-rate additive will help maximize the efficiency, purity, and stability of your fuel at each fill-up, the result of which will be mpg figures that meet or exceed the manufacturer’s estimates.
Tire Inflation
Your RV’s contact with the road can have a profound effect on mpg. It is here that the
inflation pressure and condition of your tires becomes paramount. Always ensure your tires are inflated to the manufacturer’s suggested pressure, or the tire’s maximum inflation rating. Remember, the maximum recommended inflation pressure for a tire typically offers the best fuel economy, as well as the most load-carrying capacity. When airing up, make sure it’s performed when the tires are cold, and never immediately following a drive or when the tires are warm to the touch. Then, keep tabs on everything by regularly checking inflation pressure (at least monthly), as uneven or low inflation pressure can reduce mileage and lead to uneven tread wear.
Proper Maintenance
Predictable, yes, but regular vehicle maintenance plays a big part in the maximum mpg 
puzzle. Not only will following your RV manufacturer’s suggested maintenance guidelines help ensure long-term high performance engine, transmission, and axle durability, but it will also help facilitate optimal fuel economy. Of particular importance, always confirm you’re running the correct engine oil (brand, type, viscosity), that it remains at the appropriate level on the dipstick, and that it’s changed at the specified interval. Also make sure you run OEM oil, fuel, and air filters (which will greatly help you in warranty situations), and that you’re aware of the transmission, axle, and engine coolant service intervals. A well-oiled machine will always return the best mileage.
