Gas vs Diesel – A Calculator and My Thoughts

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Gas and Diesel Prices

Like a lot of you, I never thought I’d see a sign like this again.  Here in Salt Lake City anyway, gas can be had for under two dollars a gallon, and diesel for under three.  Seeing this got me wondering, what sort of effect does this have on the old Gas vs. Diesel motorhome debate?

And then there was our recent review of the Winnebago Travato.  With Winnebago offering a diesel option on the Travato, we have a very unique situation where you can get the exact same motorhome with either a gas or diesel power plant.  That’s probably as close as we’ll ever get to a true “apples to apples” comparison for Gas vs. Diesel.  Curiosity got the better of me, and I got to work with a spreadsheet.  I’ll make the spreadsheet available at the end of the post.  But I also created this quick-and-dirty breakeven calculator you can run right from this page.  Try it for yourself with your own assumptions.  It’s fun!

The Fit RV's Gas vs. Diesel Breakeven Calculator
Price per gallon of gas:
Gasoline Miles per Gallon:
Price per gallon of diesel:
Diesel Miles per Gallon:
Price per gallon of DEF:
DEF miles per gallon:
Extra cost for diesel engine:
Miles until Break Even:

I don’t mean to start a holy war with this post, and I’m not necessarily out to change anyone’s mind.  Heck, I don’t even know if I’m changing my own mind.  Nevertheless, the results of my little cost comparison are intriguing.  The cost savings from owning a diesel just aren’t as great as you might imagine.  Here’s a little snippet from the spreadsheet to get you excited (or angry).

GasvDiesel Result 1

That’s right.  With the assumptions I used here, the longer you own the diesel, the worse and worse the financial picture looks.  Here’s where I got my assumptions:

  • The price of gas and diesel is what you see in the picture, except I added 10 cents per gallon to account for mid-grade gas.  (In Utah, the lowest octane grade is 85. The Promaster requires 87.)
  • The mileage for the gas-powered Travato is the long term mileage posted from a popular 2014 Travato blog.
  • The mileage for the diesel ProMaster is frankly an estimate, but in line with what I’ve heard from both Winnebago and the ProMaster Forum.
  • Estimates for DEF mileage were all over the place.  I found some as low as 300 miles per gallon, and as high as 1250.  So I shot for the upper middle and used 1000.
  • DEF cost was from Amazon.
  • And the extra cost for the diesel engine was directly from Dodge’s “Build and Price” website.

You might argue some of these assumptions, but that’s why I’m giving you the spreadsheet.  The one assumption you could argue most easily is that the gas prices we’re seeing right now aren’t going to last.  So when you plug in more realistic recent prices for gas and diesel, you’ll find that you will break even with the diesel… EVENTUALLY.

GasvDiesel Result 2

Like, after 470,000 miles eventually.  Still not looking good for the diesel.  To put this into perspective: our own (non-DEF) diesel, Das Bus, was new in 2003.  This was 12 years ago, back when Lance Armstrong was still either winning or not winning Tours de France.  (Now there’s another holy war I want to steer clear of!)  Anyway, today, she’s got about 120,000 miles on her.  That’s just over one fourth of the way to making up the difference above!

Now being fair, this spreadsheet just looks at consumable costs, and the up front cost of the diesel.  There are a number of things I didn’t consider here that should still factor in to any “Gas vs. Diesel” decision.

  • Diesels generally retain much more of their resale value.
  • You’ll enjoy an extended range with the diesel.  If going 500 miles or more between fill-ups appeals to you, then this is something to consider.
  • A diesel motorhome might actually make it to 470,000 miles.  Gas… maybe?
  • Gas or Diesel – how many miles are you actually going to put on your motorhome?
  • Do you want diesel fuel on board for some other purpose? (Espar heater? A diesel generator?)
  • Maintenance costs and needs are likely to be different for gas and diesel motorhomes.
  • Is wondering “Does this station have diesel?” something you want to think about? (Not all of them do, and Stef and I have been annoyingly burned by this on more than one occasion.)

And there are probably more than that. Even so, when I actually sat down and did the math, I was surprised at how the numbers turned out.  I’m not yet ready to completely give up my diesel snobbery.  But after going through this exercise, I’m having more of an open mind about the Gas vs. Diesel question.  And please remember, I’m just presenting information for you.  I’m not necessarily trying to tell you that you need one or the other – that will depend on your individual circumstances and preferences.

And now, about the spreadsheet.  You should be able to just change the assumptions in the top part and watch things change.  In addition to the break even mileage in yellow, there’s also an operating costs chart, and a graph in case you want to see things presented those ways.  With some of the assumptions from above, the chart looks like this:

GasvDiesel Operating CostsAnd the graph looks like this:

GasvDiesel Operating Costs Graph

I’ve protected the formulas to keep you from accidentally changing anything, but there’s no password on the sheet – if it asks you for one, just hit enter.

Gas V Diesel

I can’t decide if I’m curious about or fearful of the comments you might leave, but feel free to do so anyway down below!



James is a former rocket scientist, a USA Cycling coach, and lifelong fitness buff. When he's not driving the RV, or modifying the RV (or - that one time - doing both at once), you can find him racing bicycles, or building furniture, or making music. In his spare time, he works for a large IT company.

    93 thoughts on “Gas vs Diesel – A Calculator and My Thoughts

    1. Shane Sykes

      I love your calculator. I just ran the comparison for a new 2020 Jeep Wrangler gas vs diesel. The diesel engine pays for itself in a mere 1,102,535 miles. What a bargain!

    2. D JamesHeaton

      Hi Jim,
      Your calculator is terrific. When we ordered out early 2017 “K” in Dec. 2016 (delivered end of April ’17) I only briefly considered the dilsel as OE. Of course, now not available at all. If I had been towing all the time I might have considered it…but we don’t and weren’t planning to do so. Consider that small Class B van-camers don’t carry a.not a lot of propane…a 10-12% less efficient propane powered Onan v.s. gas, the diesel cost and maintenance hassle, and it was a no-brainer: stick with gas.

      I would take issue with you on gas MPG. I consistently, now @ 38.5k mi., enjoy 16.5 – 18.2 MPG on the level w/chassis AC engaged, fully loaded (I’m @ 8.4 – 8.5k #) and only gentle breezes for or against. Of course major hills and a hell of a head-wind, and the MPG can drop 10% for same 2000 RPM and 63 MPH

      With the FCA Pentastar 3.6L the “sweet spot” where the RPM:OUTPUT curve is most efficient, is right after slips into 6th gear. I drive @ 2000 RPM and a real 63 MPH. For a 10% increase in velocity the curve will require an 18% increase in RPM. That curve is exponential with more and more RPM for a deminishing increase in velocity.

      All this to say that your 15.2 MPG for the ‘T’ suggests someone has a heavy foot or is in a foolish hurry. If you’re in a hurry, why are you in an RV?

      1. James - Post author

        We typically travel at 68 mph, and on both ProMaster RV’s we’ve had, we get 15 mpg. Consistently. All the time.

        In particular, in Salt Lake City, where we were living when I wrote this piece, EVERY trip in the RV contained mountain climbs. There are also typically winds – one of the reasons we’ve only deployed an awning 5 times in 5 years. Further, Lance runs a bit heavier than the weight you quoted when we’re fully loaded.

        1. Donald James Heaton

          Jim, thanks for thoughtful and prompt reply…particularly for your posting dated back in ’15. In the midwest, like going to visint family in NJ, largely on interstates (from home in Kalamazoo) I will consistently enjoy 17.2 – 17.6 MPG for the overall 1400+ mi. trip, and we’ve done it ~ 10 times.

      2. Matthew W Polhamus

        As a semi-retired semi truck driver with 4,000,000 safe diving miles during a 35 year career, I’ll choose diesel. My current trailer is a 2020 Grand Designs Solitude 375 RES 43 foot l9ng gross weight of 16,000 pounds. Tow vehicle of choice is a 2020 F-450 Super Duty. Our former coach was a 1999 Itasca Suncruiser 37G 38 feet long gasser. My choice is diesel for several reasons. I’m obviously very comfortable with diesel equipment, locating fuel has never been a problem for me. Pulling hills and mountains is a lot less stress on the diesel than the gasser, as is flat cruising. Diesels are built more robust than gas motors. My prior tv was a 1999 F-250 Super Duty V-10 gas. When we parted ways it had 209,000 miles rang up. Very trouble free vehicle except as gas stations. Towing was 7-8 mpg unladen 13. It was not in any way, shape or fashion adequate for towing our new camper. Nothing against her, just not the right tool for the job. Yes, maintenance may be higher initially for diesel, but over the entire life cycle it may be very similar. As they say, your mileage may vary. (Pun intended.) Your calculator gives my payback at 45,480 miles. Seeing as I am a curmudgeon, I keep my vehicles until they are scrap. Others life cycle may be shorter. It comes down to using a non emotional, accurate assessment of your needs. Your calculator was very helpful for a portion of the assessment. Rember though, it was engineers whom designed the root of evil DEF and DPF systems . So for me, it’s DBF. (Diesel Boats Forever) Thank you for your efforts in designing the calculator.

        1. James - Post author

          Regardless of how anyone’s personal decision turns out, it was my hope that the calculator would be useful to people.
          Glad to hear I hit the mark!

      3. Mike Parkerson

        Why don’t truckers drive gas tractors? They don’t. They don’t exist. A diesel tractor is designed to go 1,000,000 miles before major service. I’ve never heard of any gas powered truck going that far, period. For longterm cost efffectiveness, ergo value, go with diesel. Still, it’s apples and oranges. Motor homes usually aren’t driven a million miles. Choose your favorite.

        1. Jeff Amory

          I worked for a fleet that had 50 CNG gas tractors and 220 diesels pulling same loads up to 80,000 pounds. gas tractors got 5.5 mpg with a lot of breakdowns and diesels are getting 7.5 mpg very few breakdowns

    3. Cecil Treadwell

      Owning a class B motor home has so many variables.
      But breaking down and needing to be towed to the closest authorized garage is super important as well as what the repair costs will be.
      It is usually a more convenient and/or lower cost event to have a gas powered RV serviced.

    4. Diana

      Hi James. How did you calculate operating costs? Did you include costs of maintenance and repairs? Oil changes, brake jobs, tires, etc.? Major repairs? Insurance & registration? Smog checks and repairs? What did you include in actual operating costs of a class B? Or did you calculate based upon the tax write off of cents per mile cost?

      1. James - Post author

        That little calculator doesn’t take operating costs into account. There are simply too many variables (many of which you list) and you’d have to make too many assumptions to make a general-use calculator.
        So basically, the calculator only takes into account the few variables you see there.
        Scheduled maintenance, emergency maintenance, tax breaks, etc, are left for the end user to figure based on their own situation and set of assumptions.

    5. JJVA

      James, I am sure you know that Mercedes Benz will soon be manufacturing in the U.S., its new, 2019 Sprinter GAS and diesel models, with the gas version around $6,000 less than the diesel versions. I like all the MB safety features, e.g., braking collision assist. I assume they will be included on the gas versions.

      1. James - Post author

        There are lots of rumors floating around out there about the new Sprinter versions.
        This is giving me an idea for an interview with my Sprinter contact to set the record straight… Hmmmmm…..

      2. Dennis

        I just gave up on my diesel burner for RV & went to gas. The fines against VW for diesel particulate are a factor in thinking of what diesel is doing to living things with lungs at least & can’t figure in the dollar column, but I’m liking the idea of cleaner air, and your chart is an interesting sidelight to the whole argument. Keep up the good work!

    6. Mike

      Good Article, James and it mirrors my conclusions financially. It comes down to cost per mile, not miles per gallon and cost per mile is a function of fuel cost and distance per unit of fuel.
      Of course there are other pro’s and con’s for each type of fuel but based on pure cost per mile gas is cheaper. (as is the purchase cost of the coach)

    7. Stephen Monteith Albers

      Here’s a different perspective. Instead of becoming joined at the hip to an expensive complicated mobile home juggernaut that can only lumber down paved highways from one over-priced RV slum to another, downsize. Buy a vintage Mercedes diesel car or wagon for ~ $3,000. Zero time it for ~ $3,000. Then invest in a lightweight boodockable travel trailer that can revel in traversing logging roads and cow paths to the beautiful natural settings for free. and never see a trailer park.

      1. James - Post author

        But then the passenger can’t go to the bathroom while you’re driving. And you’ve clearly not met my wife… 😉
        Good points though, and a lot of the same reasons we keep it small with a camper van ourselves.

    8. gearnuts

      hey james, stumbled across your ‘internet guy poop experiment’ vids and have been entertained for days by your channel. great work by you and stef! i have been considering the diesel vs gas ford transit, promaster plus sprinter as well and it seems to me that since the emissions standards requiring DEF have kicked in that manufacturers still have a lot of work to do to get the platforms ironed out. maybe it’s just an issue that forums isolate but it seems that a lot of folks have had bad luck with say 2015-present diesels by ford, dodge, and sprinter. having never owned a diesel, that research and low fuel prices has shied me away from the platform for now. curious if any of your friends in the field, leisure travel, winnebago, etc have reported a notable increase in issues on current diesels.

      1. James - Post author

        We don’t hear much about chassis trouble from our RV manufacturer friends unless it’s a big recall or something.
        Any maintenance issues with the chassis would be handled through the related auto service network.

        For the record, we haven’t really had any issues with our ProMaster (that I didn’t cause myself).

    9. Jack Titchener

      I never knew that diesels retain much of their wholesale value. I can see the benefit to running on diesel as there is better gas mileage and it is more reliable. I’ll have to consider your information on gas and diesel the next time I fill up the car.

    10. Gene

      Found this to be most informative. We are in the very early stages of RV research and, of course, one of the key questions is gas vs diesel. Frankly, I didn’t have a clue until I read this. For our likely 6 to 8 short trips throughout FL each year, and maybe an occasional trip to Atlanta to see family and friends, I think gas will serve us best.
      Now if I could just settle in on a “B” vs “C” class, I’d be in business. For our needs, I think either would do the job very well. It seems the value proposition is better right now (2017) on a “C” class. I’ve already checked out the insurance cost and HOA restrictions, so we’re making progress.
      Thanks, again, for an excellent article, James — well done!!!

      1. James - Post author

        Glad you found this helpful!
        Since I wrote it, gas prices rose, and are now back down almost where they were. The calculator works in any case!

        1. Gene

          Thanks, James. I think your points about finding reliable diesel mechanics, fuel, etc. are actually more important to me than the actual cost of gas vs diesel. So, while the calculator will work with varying gas prices — your other points helped drive my decision. Still looking for a reliable used unit — will likely wait until the fall or winter to make a purchase — right now it’s a sellers market for sure.

      2. Gordon

        Hi James – another thank you for this. Like others below I am struggling between gas and diesel for a B class. Here (west coast of Canada) diesel is currently slightly less expensive than gas (both are high compared to most other places). My concern is the maintenance costs of the diesel for post 2010 engines that have the newer pollution requirements. Many posts about issues and the challenge and costs of finding a Mercedes dealer to work on. That said, it seems like issues if any tend to be on the higher mileage vehicles (over 100,000 miles). So for me it comes down to the reliability of the Mercedes (usually) diesel. No question that they will last a lot longer than gas, but trying to determine if there are some serious interim maintainence concerns that you (or others) are aware of?

        1. James - Post author

          Well, when we had our (pre-2010) Sprinter, we found maintenance costs to be a bit high as compared to the gas engine we have now.
          But I’m no diesel mechanic, so I really can’t tell you what it should cost (average/long-term).

        2. njsarn

          Thanks James for the calculator. Here in California the gasoline price is $0.20 less than diesel. Since there’s no pricing for a non diesel Sprinter, it appears the diesel is a better deal. Given the same amount of fuel tank capacity, I have longer distances that I can travel with diesel engine. Since the diesel engine has more torque the Sprinter van goes up the hill without shifting the gear down or gear hunting versus my gas engine. As far as maintenance cost, I do all the maintenance myself and should not enter into the equation. Any case, each to his or her own.

        3. Tom Page

          I recently purchased a 2009 Diesel Winnebago View. It is a real pain in the A$$ trying ot find a mechanic who works on Mercedes diesel sprinters. Even at the local Mercedes dealer there is only ONE sprinter mechanic.

          When I trade my View it will definately be to a gas RV.

          Also, I almost ran out of Diesel driving around looking for a gas station that sells deisel. If your off the beaten path it can be difficult, almost ran out of gas on a couple occasions.

    11. Patti Walker

      I have been researching my first Class B (first RV) purchase for several months now and I go back and forth on gas verses diesel – with diesel winning out. Until now. Thanks for evening the playing field. Especially with the question, how many miles do I plan to drive? Great research and comparison costs. I will save it and read again – along with all the responses.

      p.s. I’ve been following you since I started researching and get a lot out your videos and posts.I hope to run into you one of these days, not literally 😉

    12. Hervey Forward

      We are researching B vans. After four trips across country on a Harley a B Van would B a luxury!

      James as a retired Automotive Vocational Instructor I agree with your Diesel vs Gas calculations. Besides the engine cost the Diesel Exhaust systems are way complicated and there is always varying fuel quality problems. The fuel filter maintenance and the cost of oil changes is much more.

      It’s hard to give up the manly Diesel noise, the so-called Diesel Snob effect, and the stump pulling torque.

      We started out looking at the B van Diesels and now find we are leaning toward the Travato gas. Winnebago will mount functional bike and roof racks. Pleasure Way for example will not.

      Have you been happy with the performance of the Gas V6. That engine has received several awards and with proper synthetic oil changes can go 200k + miles.

      However, if you research the many ProMaster chassis reviews online it’s scary how poorly it is rated.

      Will you B testing the Winnebago Paseo with the new 3.5 Eco-Boost? We enjoy your videos and informational reviews.

      1. James - Post author

        We’ve been completely satisfied with the performance of the gas V6 in the Travato. Anything more would be overkill. And any problems we’ve had with the ProMaster chassis have been entirely self-caused.
        We will likely do a review of the Paseo sometime this summer.

    13. Sam M

      Purchasing Class A or C RV with slide outs So, Gasoline or Diesel? Which is best? Retiring going to be traveling quite a bit, full time. No longer than 34′ towing a small car if class A.

    14. Erik Laursen

      The gas station you have pictured I think is an anomaly. With the mileages in your spread sheet diesel prices more than $0.57 higher than gas will always push the overall cost of diesel more than gas. Any difference less will make the fuel costs for diesel push downward and close in on that $4500.00 initial investment. As of 11/25/16 the difference between gas and diesel on the AAA web site is $0.16. Using the stated gas price and pricing diesel only 16 cents higher the break even point is 171907 miles. The higher the prices go the sooner the break even is reached. But as stated above this is only one small part of the diesel vs. gas debate.

      1. James - Post author

        Well, gas prices did get abnormally low there for a while.
        Regardless, the math in the calculator is correct. If you’re seeing different prices for gas and diesel, go ahead and run them. Sounds like you have.
        As you point out though, the break-even mileage is just one part of the decision.

      2. Bill Bly

        I bought the Winnebago ERA with Diesel. I just happen to like diesel motors more. I find the cost is about $.50 more per gallon. One consideration is I’ll get easily 200k miles on mine while a gas engine you’ll get 80-90k miles before you start overhauling the engine.

    15. Max

      I have a diesel Jeep Liberty. Bought it because of that “amazing torque” and “better mileage” It has neither (well, the mileage is a little better I guess) and I hate the day I bought it. In Canada, where I used to live, regular gas and diesel prices are more or less the same but still diesel isn’t available everywhere. Maintenance is definitely more expensive. I consider getting a gas Promaster and converting it into a poor man’s version of what you guys have.

    16. Chuck Griffiths

      Another thought that I remedied with a 75 gallon portable diesel tank in my GMC 3500…that is traveling in Mexico…where there is no ULSD. In looking for a new Class B or C that will replace my truck and trailer (that is a whole ‘nother story),I will only look to gas as it is more “universal” given the continuing manipulation of
      EPA standards for diesel, plus the ridiculous cost differential which once again is raising it’s ugly head!

    17. wes

      It’s sept of 2016 and where I live diesel is now cheaper than gas, but this is the kind of topic is so dependent on so many factors from region to region and tech. it will never end. Using your calculator I came up with 38000 miles to break even. If you carry a lot of weight their really isn’t any choice diesel is it and in mountainous terrain again same answer. Used to be diesel with no igniton system was supposed to be cheaper to work on but not anymore. Domestic (ford, chev Fi er chyrsler) chassis makers have a huge advantage as parts and service are readily available everywhere. Broke down in Picurnose, middle of the prairie, you can easily find a domestic dealer to charge you for your usage of their breathing air and toilet paper. Plus if you know that this is a recurring issue you can stock up on spare parts and maybe even fix it your self. Interesting point about the travago as the pentastar V6 is one of the best engines in the world mileage and hp in a single package. Obviously the then offered diesel was not. Probably why it’s not offered anymore by winne.

    18. CarlNH

      I don’t currently own an RV but will soon be in the market for a van-sized Class B. I am also a diesel snob but now beginning to question the wisdom of same. Maintenance on newer diesels is apt to be a LOT higher than a gas engine. The culprit is the draconian emissions control systems required for diesels to meet EPA/DOT regulations. Things like particulate filters, multiple cat converters, electronic controls, expensive sensors, etc. This I am learning through my current ownership of a VW Jetta Sportwagen TDi (2011). DPF cracked just beyond warranty for $3K. Even if they don’t crack, they require replacement when filled up… maybe 120K to 200K miles depending upon your luck. Another $2-3K. High Pressure Fuel Pumps for the direct injection engines have been troublesome (not mine YET) in that, when they grenade, they take the entire fuel system along with them to the tune of $5-8K. Anyway, just more fuel (of your choosing) for thought.

    19. Tracy

      I’ve noticed each blogger has been male….now why is this? I find the entire blogging for your calculations very interesting but even more surprised their are others just like you (my husband being one of them.) He would love nothing more than to sit down and…….calculate! We are wannabe Travado owners so everything on the blogosphere is read with interest…even the calculations.

    20. Dog Lover

      In addition to the costs you mentioned, has anyone discussed the costs of maintenance (e.g., oil changes, etc.) of diesel vs. gas?

      1. James - Post author

        I didn’t mention it specifically in the article, but my un-scientific general impression is that service on the diesels was more expensive. Of course, that could also have something to do with the diesel I had being a Mercedes…

    21. roger nadeau

      I purchased a sprinter for the camper use as it is larger than the travato. No one is using the ford transit for conversions yet. That is what I was looking for with a v6 with ecoboost. I had to settle for the sprinter 3500 chassis.

    22. Mark Bowker

      I did not read every post to see if anyone mentioned resale. If the diesel cost lets say $4,000 more new, it should get close to that when sold or traded and take the price for the diesel option out of the equation.

      1. James - Post author

        Yeah, resale was mentioned somewhere. Diesels definitely hold on to their resale value better. So if and when you trade in could be taken into account.
        (Kind of like predicting the future!)

    23. Robert Meehan

      On the east coast Gas is 2.01 Diesel is 2.09 DEF is sold at the pump and was 2.79 last time I purchased some. At least the form doesn’t read NEVER LOL. For torque and exhaust braking alone I would still pick a diesel in a large RV or in my case a 3500 RAM for my fifth wheel.

      1. James - Post author

        Last time I ran it here, the answer wasn’t “never”, but it was close enough to never that I still felt good about our gas RV.

    24. John

      As a former owner of both a gasser Class A (30′ with Ford 460), a 38′ DP with Cummins C8.3 (mechanical), and now a Pleasureway Sprinter with the the 3.0, I totally agree that for virtually all RV use, the gasser will be the more economical choice–by far, and on several fronts.

      One other consideration is that gas engines tolerate sitting a LOT better than diesels. When you consider that most RVs will sit in storage most of the year and then be used for a few hundred or a couple thousand miles again before sitting unstated for a few months, the diesels don’t tolerate that nearly as well as gasoline engines. Diesel engine seals dry out, and then the engine leaks oil. A lot of oil. Before I sold my DP I spent $7000 to have that Cummins engine resealed–which was money I never recouped. (I had just driven it 2400 miles, and it leaked 5 gallons of oil on that trip. Not quarts, but gallons.)

      And then you haven’t even touched the subject of how finicky the newer MB engines are for fuel quality, and how they don’t like biodiesel. My experience is that sometimes it can be challenging to find diesel fuel that isn’t B6-20 when MB specifies B5 or less.

      If you drive it a lot, diesel is great for torque and longevity as well as “chic” factor. However, unless you’re driving a huge heavy motorhome or pulling a heavy trailer where the torque is mandatory, gas will beat diesel on economics every time.

      1. James - Post author

        Awesome insight, John! Glad to have you chime in with your real-world experience.
        Thanks for reading!

      2. Sharon

        Thank you, John! Now, this is the post I’ve been waiting for. Someone that has had a gas and diesel Class A to chime in on this discussion. I’ve been researching Class A’s for a few months with the absolute intention of getting one in the fall of this year (2018). At first, I was all about the diesel and wouldn’t even consider a gasser, but the price of gas is going up now and diesel is $.10+ higher not to mention the required DEF every 1,000 miles, plus the problems that arise from having a diesel motorhome in storage when not driving it. Yes, my research states the diesel has a higher resale value if properly maintained and can tow mountains better, but it costs more to purchase and maintain. With all the knowledge I’ve obtained I began last week researching the Class A “gas” RV that I will get now. I’m a single female and I need to be able to get fuel and service when I need it. Owners on YouTube and in forums are constantly talking about the problems they encounter when their rig needs service and usually the dealership has the diesel rig for weeks at a time or unable to find a mechanic to work on it. Keep the comments coming…loving it!

    25. Steve

      Great, now I’m staring at every gas station I go by (on my bike) to see the spread between the two fuels. I was definitely going with diesel (sprinter) as I’m comfortable from my time on boats. But your blog post got me thinking & searching.
      Some background – even though slightly dated gives a quick review

      Current USA Price comparisons:

      It’s amazing that the Transportation industry has not revolted over the diesel prices & tax given the critical nature of trucks, buses & trains but guess they just pass it through to the gas driving public in all sorts of ways.

      I have not seen the dramatic spread shown in SLC example……In fact, it appears that in most places the spread has narrowed dramatically. So I continue leaning toward diesel maybe look at the 4 cyl turbo / 7 speed too.
      Just depends as I narrow in on developing my short list of Class B candidates.

      1. James - Post author

        At most places around here, Diesel is back to costing more than gas again.
        If only we could predict the future!

    26. Alain Roy

      I am curious about the fuel gelling comments. For now I can’t comment on RV’s since we have a TT. But my Jeep Grand Cherokee is an EcoDiesel and I have used it for the last year during our norther Quebec winter (I probably hit minus 35 last New Year at my in laws) and have had no issues with gelling. Up here we have “winter diesel” starting usually in October in all gas stations. I assume it’s the same in all northern states.

      One issue that concerns me is the use of DEF in colder weather. I had to change the catalytic converter with less than one year of use and the technician said it had something to do with the inefficient way the motor uses the DEF in cold weather. Whether this is a chemical, mechanical or software issue I don’t know. Since I and considering the diesel ProMaster, which also has an Eco Diesel engine (but not the 3LV6 I have on the Jeep), this is a concern if I want to use it in the winter as a duel use second vehicle.

      Without opening a can of worms, I wonder how the “Volkswagen” diesel fraud will affect the whole class B diesel market (availability, resale value, etc).

      1. James - Post author

        We never had fuel gel in Das Bus either. But I have heard it could happen. My understanding is like yours – in the states where it’s needed, a special blend of diesel is sold during the winter.
        I’ve never put that to the test though – and don’t really want to!
        The DEF comments are interesting. Have to check on that.

    27. James

      Okay, here is a little perspective from a oil hauler in North Dakota. Diesel is going to be more expensive on average because that is what big trucks use to get around. They HEAVILY tax diesel because they want the revenue from the big trucks. Currently I haul crude into a refinery that produces only diesel and the station down the road tends to sell both gas and diesel for the same price. If you look at the tax break down of your fuel you will find when gas is $2.50 you are actually only paying about $0.70 a gal for gas and $1.80 in tax. This varies state to state and city to city. Diesel tax rates are much higher even though the actual fuel is cheaper.

      Also, being that I work in sub zero temperatures in the winter you neglected to mention the #1 problem with diesel is Gel. When your fuel gels you are dead in the water with no heat. And in ND that can leave you dead in the truck. To try to keep the trucks warm you have to plug them in at about $500/month in electric. Or never shut them off and they can still gel at idle. I love my big trucks and diesels but these are things that can blind side people if they are not aware. IE someone from SoCal drives their TDI VW up north and it wont start in the morning because it has a tank and fuel filter full of JELLO.

      I love your site. I found you on UTube with your black tank tests and immediately subscribed to your Email.

      1. James - Post author

        When we had a diesel RV, I was a little concerned about the gel thing – but it turned out never to be an issue.
        Most RVs probably won’t find them in the extreme cold that the big trucks need to operate in. We do go out in the winter, but if it were consistently below zero, we’d probably stay home!
        Glad you liked the YouTube videos and tracked us down. Welcome aboard!

    28. AL

      With the prices in SoCal, regular at about $3.50 and diesel around $2.99 ( for quite awhile now), the break even for me is about 58k miles using your calculator. I agree on the convenience of gas fill ups and no DEF, and it will take me 4-5 years to reach that many miles, yet I still question if going diesel would be the better way to go, with further between fill ups, and more torque. After having Lance for a month, any second thoughts or observations going to gas from diesel? Any list of pros and cons come to mind? Enjoy your web blogs and your reviews.

      1. James - Post author

        Oh, if only I had a crystal ball, and could predict what gas and diesel prices would be like for the life of our RV!
        I’ve always thought diesel should be cheaper than gas. I just wish it hadn’t picked “exactly when James buys a gas RV” as the time to do it… lol.
        More torque is nice. That’s probably the thing I miss most about the diesel – even more than the mileage. You just have to wind the gas engine up faster to get the same kind of output. It feels strange, but I’ll adapt.
        I am looking forward to not having to find a special mechanic to work on our gas engine.
        Beyond that, I don’t really have any additional pros and cons yet. Maybe I’ll try to collect my thoughts after our first oil change. I know what they charged for that on the Sprinters. Surely the gasser can’t be as bad?

    29. Jon and Susan

      Have enjoyed your videos as we search for our first RV, likely a Class B. Your presentation of Diesel vs Gas is excellent, and I too was surprised to have the wool removed from my eyes…as most things I’ve heard seem to give Diesel the ‘cost effective’ option for economy. I feel now that it is likely not cost effective, unless of course those other benefits weigh heavy with the RV owners needs… in they need the quitter Diesel with more torque. One thing that should be added (perhaps to the things to consider with Diesel) is how much more quiet (so I have heard?!) the generators are over Gas…when you need to run one at a camp ground/etc. Thoughts? Again, enjoy your videos and now your blog….

      1. James - Post author

        I actually have it in my mind to do a generator sound-off. I have similar vehicles with gas and propane generators available to me now. I wonder if anyone here has a diesel generator? Something to think about.
        Just to make sure you’ve got the whole picture, the higher resale of the diesels is something to keep in mind. It can be significant down the road. And they do better if you plan on towing regularly. Don’t know exactly what your situation is, so that may not matter to you.

    30. LisaD

      OK – if Diesel prevents me from stopping as frequently to fill up – then I’m getting Diesel LOL I HATE getting gas. Yes I’d rather stop to spend more time walking my dog or playing with her then filling up and walking her. Especially in crappy weather situations or late at night, in unfamiliar areas etc. Good point. Bam!

    31. MotoRV

      I second the appreciation for your articles and thoughts on RVs. Like many others, it is hard for me to believe that the big RV companies cannot produce a true 4-season B/B+ class vehicle for a reasonable price. As an owner of a diesel and hybrid car, I can see the benefits of going diesel despite the higher fuel cost. 1) Torque, 2) Eliminating LP for heat, 3) Longer Range 3) Towing 4) Quieter Operation (more engine encapsulation).

      I work 100% telecommuting and having the luxury of being off grid for several days at a time is a plus.

      James are you any closer to discovering the best B/B+ 4-season RV at this time? Your research has been very helpful.

      1. James - Post author

        Glad you like the site!
        The true 4-season capability seems to be the sticking point with most of the coaches we look at. The small size of the B vans makes it a challenge to fit everything inside in the heated and insulated space. B+ manufacturers have less of an excuse – but even with those, since the coach is larger, people expect more features. That tends to crowd things to the outside.
        So, in short, I still haven’t found our “perfect” next RV, and I’m still trying to convince Stef that the “perfect” one is the one I’ll build. (But I’m not getting very far with that…).

        1. Ian (Zyzzyx)

          We’re jumping into the DIY-RV world. Currently have a diesel Promaster on order. Will then be building it out myself with a structure based on 80/20 aluminum t-slot extrusions. Should be interesting.

          We looked at B/B+ builds and found they had too much ‘stuff’ in them. We want more of a deluxe ‘iron tent’, but need to have convertible cargo areas for weekend trips; dogs and dog crates for her, recumbent bikes for me. Doing the build ourselves we’ll get the layout we want (though it will be vaguely similar to the Travato, but with the wetbath on the other side)

          I’d say you just need to jump in and do the RV yourself. You have the experience for 1) knowing what you need/want in an RV, and 2) knowing how to build it.

          If you haven’t already (but bet you have), spend some time at the Sprinter and Promaster forums (even the Transit forum) and see what kind of RV builds folks are doing. There’s some great (and not so great) ideas out there.

        2. James - Post author

          Appreciate the vote of confidence! How long of a lead time did they give you on your diesel ProMaster?

      2. Wade Anderson

        James – Good article. I see that you are hoping to own a true 4 season B/B+. Our 2005 Chinook Concourse (21 foot length) with the V10 (also had diesel option) comes close to fitting the bill with a very minor modification from stock for the shower drain; all pressure lines are inside the coach & we have tank heaters & insulation on the black and grey water tanks. I suggest if you are looking for true 4 season, you should also be considering gas over diesel. Diesel can gel in cold temperatures. In high school I lived in an area where farmers faced this problem regularly. While there are additives, that also adds to cost of running a diesel in the winter and increases the risk of being stranded. Advantage for true 4 seasons in most any temperature: gas. 🙂

        1. James - Post author

          Our new Travato will be gas!
          (Though, if it’s cold enough to gel diesel, we probably won’t be RVing. Well, most probably…)

    32. Dillon

      interesting comparison.

      gas is alot cheaper in purchase price and (with currently prices) cheaper with fuel. but unfortunately if you’re looking for a “luxury” coach (i.e. airstream, advanced rv) a gas just isn’t offered by most manufacturers

      1. James - Post author

        Alas, it’s true that the higher end offerings gravitate toward diesel.
        But with the ProMaster, we’re starting to see some of our favorite manufacturers offer this chassis, which can be had in either fuel. Perhaps there are even more options in our future? (I don’t have any insider information here… just wondering.)

    33. Tom Boles

      Our adventures driving a Ford E350 with the V10 (gas) engine towing a 33′ travel trailer suggests that running out of gas in the US is mostly bad planning, wherever you are. We’ve never lacked for power, oil changes and basic repairs are cheap and easy to come by and I prefer to get out and stretch every two or three hours anyway, so range is usually not a problem.

      Thanks for the calculators and discussion!

    34. Ray & Cher

      The most recent Lichtsinn Motors RV UStream webcast on February 18 was devoted to the subject of gas vs diesel. They are a Winnebago dealership in Forest City, Iowa. If you can find it recorded, I’d recommend watching the program. Ron was saying that the cost for the diesel on the Promaster is about $5,000 more and the comparative mpg is about 15.5 for the gas versus 18 for the diesel. The diesel supposedly retains value better and has more torque lb-ft. which could be important if you anticipate using the vehicle for towing. For my needs, I decided that I cannot justify the added expense for diesel. The program also covered difference in Class A engines and there Lichtsinn was more convincing in selling the virtues of diesel pushers.

      1. James - Post author

        Interesting. Thanks for the tip on the webcast – I’ll have to look it up. And also interesting that they were only estimating the diesel at 18! I would hope its better than that.
        One of the reasons we’re small-RV people is because I don’t ever want to have to mess with towing. At least not regularly (I could see one day towing a wave runner or snowmobile occasionally). For any light-duty towing I would do, I think the gas would be OK. They’re not making it up about the diesel resale though – it’s pretty good.
        Class A is a whole different ball game, and I haven’t researched it enough to comment, although the conventional wisdom does seem to lean toward diesel pushers.

    35. Russ

      cool tool James. I suppose this is really an individual thing, but for me it will be important to know that whenever I want to jump in the van and take a quick trip, I’ll be more likely to do it knowing that I’m getting great mileage with the diesel. Sure the math says it will cost more, but I’ll enjoy it more….and have the higher resale value when I’m ready.

      1. James - Post author

        I know what you mean, Russ! Once you purchase the RV, that extra you paid for the diesel becomes sort of a sunk cost, and you don’t think about it anymore. But you feel the fuel costs every time you fill up! I know Stef and I will sometimes estimate fuel costs for a trip we’re thinking about – and not once have we ever wondered if the extra we paid for a diesel should factor into it. Totally psychological, but I get it. (And yeah, the resale on diesel class Bs is pretty nice too!)

    36. Jim

      Oh, one other thing: I’ll buy used. Seems maybe a used diesel could tilt me in its favor. Limits me to Sprinter, but maybe I can find one that works. So, I think used vs new puts the gas/diesel cost in a different light.

      1. James - Post author

        Maybe. If you get a used diesel, you may be able to find one that’s old enough not to use DEF, like Das Bus. That helps.
        (I made sure you can just enter 0 for the price of DEF in the calculator, if you want to play around with that scenario.)
        Also, if you’re buying used, the longevity of the diesels works in their favor.

        1. Jim

          Thanks James! I just finished watching your review of that Pleasure Way Plateau XL in Dallas (?). I’m like you, gotta have four season use! I love that you crawl under these RVs. Keep doing that!

          Since I’m older, I’m not too worried about diesel/gas driving costs differences, mainly just reliability. Ethyl and I are wanting to just go all over America, stay as long as we want where we want while we can! Class B with a good bathroom, that’s what I’m needing.

    37. Jim

      As a geezer, I need to stop anyway. But, with our dream of going all over west, I think I’ll just carry a couple of 5 gallon cans. Gasoline, that is.

    38. Mark Freeman

      James – It’s even worse than you are charting. The 87 Octane requirement is at sea level. At our altitudes (I’m in Colorado), 85 Octane is equivalent to 87 at sea level. So you don’t need to purchase the mid grade.

      1. James - Post author

        Good point! I did think about that before posting, but ultimately decided to go with the 88 octane because that’s what I’d fill up with anyway. We’ve taken enough RV trips where we wind up at lower altitudes, so I would just fill up with the 88 so I wouldn’t have to think about it. But, as you point out, if you can fill up with the 85, then yeah, it looks even worse for the diesel!

    39. Marshal

      SHOCKING!!!!! I know you are sweating bullets on reactions to this post, but anyone willing to provide such a potentially useful spreadsheet analysis is ACES in my book!

      Can’t wait to dig into this spreadsheet — I will, of course, need to confirm all the calculations myself, but that will be at least half the fun : )

      1. James - Post author

        The spreadsheet was the easy part – the little calculator on the page was giving me fits!
        Let me know if you find any errors in either one.

    40. Ted

      One factor I considered when comparing Gas vrs Diesel for the Promaster is range which can be an issue when driving long distances. Assuming the tanks are the same size, 24 gallons, then the diesel could go 528 miles vrs 365 miles for the gas version between fill ups. That comes to an additional 163 miles of travel. At home we have a hybrid that goes over 500 miles on a tank, vrs a regular vehicle that goes about 370 miles on a tank. This translates into filling up the hybrid about once every two weeks compared to just over a week for the regular car. I once found myself camping in the middle of Joshua Tree National Park low on gas and just barely made it out of the park to a gas station running on fumes. So you can justify diesel by picturing yourself rumbling past a gas vehicle stuck on the side of the road, buzzards circling, waiting for the AAA truck to come with a canister of gas.

      1. James - Post author

        Ted! You’re right about the extended range being a benefit of the diesels. Stef and I really do enjoy the nearly 600 mile range we can sometimes get out of Das Bus. It would be tough to give that up. Of course, Stef reminds me all the time that it’s healthier to stop more frequently, so maybe the reduced range of the gas vehicle would be a good reminder to stop driving and move.
        I think I’ll update the post and add “extended range” as something else to consider.

        1. Ted

          600 miles per tank sounds pretty good. On the B-forums “Wincrasher” with his early 2015 gas Travato reported it was standard procedure for him to gas up with just a half tank traveling down to Florida. That would mean hitting a gas station every 180 miles or so (I’d get pretty tired of gas stations by then). With extended gas range I’m sure you can find other excuses to make frequent stops. For us it will be an antsy dog that needs regular breaks to get out and run around along the way.

        2. James - Post author

          I’ll have to check into the Wincrasher guy. 180 miles is a bit much for me. I generally wait until an eighth of a tank or so (or until Stef starts fretting) before filling up. Back East, I wouldn’t worry about finding gas when I needed it. But rolling across some of the desolate places out west – that would require some planning.

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