Campervan and motorhome fuel consumption

Fuel use by vehicle type

German magazine promobil measures every vehicle it tests on the same route of about 300 km (190 miles): 13% town, 41% country roads and 46% motorway, mostly at 100 km/h (62 mph), with the water and gas tanks full and the vehicle loaded for travel. Typical results:

Real drivers’ figures are in line: on Spritmonitor.de, the diesel Fiat Ducato averages 10.2 L/100 km (about 28 mpg UK, 23 mpg US) across 3,195 vehicles, including work vans, campervans and motorhomes. These are European diesel vehicles. In the US, if your motorhome’s gross vehicle weight rating (GVWR, on the driver’s door pillar) is above 8,500 lb, it has no official EPA figure, because heavier vehicles are exempt from fuel economy testing: measure your real mpg instead.

Speed matters most

promobil drove the same low-profile motorhome, on a 140 hp Fiat Ducato and weighing about 3,000 kg, for 191 km (119 miles) of motorway at three speeds:

Air resistance grows with the square of speed, and on a tall vehicle with a big front it dominates fuel use on the motorway. In the UK, motorhomes over 3.05 tonnes unladen are limited to 50 mph on single carriageways and 60 mph on dual carriageways, and 70 mph on motorways, like cars. Driving at 60 rather than 70 mph is the simplest way to use less fuel.

Aerodynamics: why it uses more than a car

What counts is total aerodynamic drag: the drag coefficient (Cd) multiplied by frontal area. According to the ICCT, an average European car has 0.72–0.77 m², and a large van about 1.53 m² (Cd 0.34 and 4 m² of frontal area). A campervan on a medium van sits in between. Motorhome manufacturers don’t publish their Cd; from promobil’s measurements, our methodology estimates it at about 2.8 m², almost four times a car’s.

That’s also why bikes or a box on the roof affect a motorhome less, in proportion, than a car: its baseline drag is already very high. On a rear rack they get in the way less than on top: roof boxes and luggage.

Real travelling weight

The “mass in running order” on the spec sheet includes a 75 kg driver, a 90% full fuel tank, 20 litres of water and a gas bottle. On the road you add much more: a full water tank, a second gas bottle, luggage, food, chairs or bikes. Germany’s ADAC works out travelling weight with a flat 200 kg for water, gas and equipment on top of people and luggage, and at one of its weighing events around 30% of motorhomes were over their maximum permitted weight.

Weight matters most in town and on hills, where the mass has to be accelerated. Travelling with the water tank half full and without things you won’t use saves fuel and keeps you away from the 3,500 kg limit.

How to work out the fuel use for your trip

1. If you can, measure your real fuel economy: fill the tank, reset the trip meter and, at the next fill-up, divide the miles by the gallons (or the litres by the km, times 100). How: work out your real mpg.
2. In the campervan and motorhome calculator, choose “Campervan” or “Motorhome” and enter that figure as “My real figure”. If you don’t have it, use the vehicle’s official figure.
3. Calculate the route: the split between town, country roads and motorway changes the result a lot for these vehicles.
4. Add travellers and luggage. With an official figure, the calculator already adds the usual kit: 100 kg (220 lb) in a campervan and 200 kg (440 lb) in a motorhome.