When you think of fuel-efficient vehicles, chances are RVs and camper vans don’t cross your mind. They’re a literal house on wheels, and last I checked, houses weren’t designed to be economical. But if you make clever use of the space, and really shed the weight, you can build a motorhome that gets over 20mpg. And while many manufacturers have done it, Winnebago takes the cake.

The Winnebago Travato 59G will give you impressive mileage and hot showers

The Class B Winnebago Travato 59G camper van will end up returning 18 to 22 mpg on the highway according to Camper Rules, making it the most efficient RV available. That looks like the fuel economy of a gas guzzler on paper. But when you consider that the Travato weighs nearly 12,000 lbs, suddenly a combined 20 mpg doesn’t look too bad. On top of that, the fuel tank is 24 gallons, which means you’re getting nearly 500 miles every fill-up.

With the 59G, you get a wet bath and toilet, a queen-sized bed for two, and a kitchenette for cooking. And standard features include insulated floors, four seats with seatbelts, and a rearview camera.

This camper is built out of the Ram Promaster chassis and uses the Promaster V6. The engine makes 280 horsepower and 260 lb-ft of torque. It’s a camper van that has everything, but one major drawback is the price. The Winnebago Travato 59G starts at $137,347, which is before options. And any extras you include will increase the vehicle’s weight and, subsequently, decrease the mileage.

But if you’re in the market for something cheaper, and don’t mind going used, there’s an older Winnebago RV that also gets good gas mileage.

The Winnebago Rialta 22QD gets similar milage, but is a bit older

Rated at 18 to 22 miles per gallon on the highway, the Winnebago Rialta is another Class B RV/camper van that gets excellent mileage. And these RVs were discontinued over 15 years ago. Now, the Winnebago Rialta came with two different engines, a 140 hp model that ran from 1997 to 2001, and a 304 horsepower model that ran from 2002 to 2005. Both of these RVs were engineered by Volkswagen, but which of these is more efficient is unclear. That said, I’d wager the 140 horsepower model drinks a little less gas than its beefier successor.

One thing to note about the Rialta is that it’s slightly larger than the Travato, at 22ft long in comparison to the Tavato’s 21ft. And inside, there’s room for seven passenger’s rather than four, and configurations that’ll sleep all eight people. It also comes with an extendable wet bath and kitchenette, fitted with both a microwave and a refrigerator. By comparison, the Travato only has a fridge.

And used, these RVs run a much more reasonable $40,000. That’s still not cheap, as there’s really no such thing as a cheap RV. But it’s better than spending over $100,000 on a new camper van. And with such a clever interior, making excellent use of the space, that price feels justified

In terms of economical RVs, this is as fuel-efficient as they come. And while an average of 20 mpg might not seem very impressive, for a vehicle that’s meant to haul an entire home’s worth of appliances, it could be a lot worse.