mr300ce
Mojave Desert, Ca
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Easy to remember. Running dash AC costs 1 mpg in big ole RV.
For mine, 8 mpg with AC on, 9 mpg with AC off.
In 60 miles of driving, I use 1 extra gallon of gas.
60 miles/8mpg=7.5gal gas 60 miles/7mpg=8.5 gal gas.
Running my genset for 60 miles costs about 1/2 gal fuel.
I run the genset because it does a better cooling job inside this
RV, and I save 1/2gal gas over dash AC, which doesn't cool as well.
I didn't notice any power loss going up big hills with dash
AC on. I can 'feel' the power loss in my Nissan truck w/4cyl.
I tested that. I test everything. Its in my nature.
Fulltime livin' & lovin' it in '94 Bounder 32h.
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rk911
Wheaton IL
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rondeb wrote:pianotuna wrote:Hi rondeb,
How do you happen to know the answer? At what speed?
Have tracked this over 40,000 miles of traveling. We have had a few tanks drop as low as 2.0 MPG
This is traveling at an average speed of 58-62 mph
We use the AC when we need it and we have kept MPG records for 40,000 miles. I always mark the records with a star for those tanks that AC was used.
i have meticulous MPG records for all of our vehicles including our present motorhome. the *only* time i get a putrid MPG readings like the one you mention are the first few tanks of gas at the beginning of the season. once all of the old gas (and yes, i use stabil) cycles through our 'normal' MPG of 6-7 returns. my historical MPG over 12-yrs and 82,000+ miles is 6.664 mpg.
we've been en route from silver city, nm to nashville, tn for the last several days. we've been running the dash and genny/coach AC during our 5-6 hour travel days and i'm not noticing any significant departure from normal MPG...other than i had one segment above 9-mpg. that was very unusual. today i had segments of 6.76 and 9.79 MPG. most of the second segment today was downhill and traffic was light. our MH/toad combo weighs in at approx. 23,500-lbs. most days i travel at 63-65 mph using cruise control slowing only for wind, traffic or lower speed limits.
73,
rich, n9dko
www.bananaboatbytes.com
I know a guy who's addicted to brake fulid. He says he can stop anytime.
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2000 Itasca Suncruiser 35U
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MrWizard
Traveling
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Joined: 06/27/2004
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I dont know what it cost
but I'm not driving around in a big metal oven at 100*F outside and over that inside
i even turn on the generator and use the roof top A/C
Options, always have options, and the journey goes much smoother
....
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mdprince
Santa Clarita, CA
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MrWizard wrote:I dont know what it cost
but I'm not driving around in a big metal oven at 100*F outside and over that inside
i even turn on the generator and use the roof top A/C
Amen !! I could spend a few minutes with a calculator, but, I'll just estimate it at 1/2 gallon per hour or approx. $2.50/hr. We run it if it's over 85f and the DW want's to hang in the bedroom and watch TV. Life's tuff !! ymmv
2006 Revolution LE 40E
2004 Jeep Rubicon Toad/Brake Buddy or
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concord32
Indianapolis
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Mythbusters did and episode on this very thing with cars. They found no real differance with the air on or off.
2011 Coachmen Concord 32' Triton V-10 1-slide.
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PeppyPilot
NW Chicago Suburbs
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As others have indicated, the cost is not great compared to the overall cost of owning and operating a coach. Assuming it's warm enough that you need ventilation to keep you cool, the cost may be none: opening the windows while driving at highway speeds may cost you more (as someone else posted) in decreased mileage than operating either AC unit!
We have found that with all the variables involved, figuring exact costs and comparisons really difficult, probably impossible outside of a test lab.
Our view is this: components in most recreational vehicles suffer problems (call that $$$) from lack of use, rather than overuse. We try to use every system frequently - saving ourselves money/hassle in the long run.
We like to run dash air:
mild temps
no need to cool entire coach
when fuel supply is low enough that genny may kick off
not towing
short local runs
reasonably flat terrain
(the idea here is to not over-tax the engine while using the dash air)
We like to use the coach air with genny:
hotter temps
need to cool entire coach
hilly terrain
stop and go traffic, highway back ups
towing
When we want to use genny anyway for microwave or other appliances.
We like to operate the windows:
When stopped (sometimes in bad traffic jam)
When camping
When temps are mild
In the rain, with the awnings out (difficult when driving)
When driving very slowly, like in a campground or in national/state park
* This post was
edited 05/04/12 06:13am by PeppyPilot *
CJ and Pepe
2003 Itasca Suncruiser 33V
Workhorse W-20 chassis
2004 Jeep Liberty Limited w/Blue Ox
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univmd
Maryland
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Joined: 03/02/2009
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It may cost more to open the windows instead, like in a car.
2008 Gulfstream Tourmaster
2011 Honda CRV
Blue Ox Baseplate & Socket Wiring
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sowego
northwestern corner of the Nebraska panhandle
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Joined: 03/14/2006
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I agree with other posters that using the dash AC, either &/or genny with roof airs is the way to go. The slight amount of fuel it takes makes up in comfort. Each MH is different with fuel usage in either mode. I'd not obsess over it...just use it!
If you are in the "humid" part of the country and it's hot and muggy no amount of windows open & fans running will keep you comfortable and by the way safer. Not only is it uncomfortable to drive around really hot and sweaty, it is unhealthy and I reckon unsafe. In the dry heat out west you will get baked and dried out like a prune.
Also as other posters suggested if you cannot afford to run the AC and use slightly more fuel then it is likely you will be miserable all the time worrying about all the things that will go wrong, all normal when living or traveling in a motorhome.
The same advise should go for using dash heat and the propane furnaces in winter. Not using those systems will cause a lot of misery and possible damage to plumbing.
If you have the small fans at the top edge of the windshield, turn those on and aim them so they move the air around even more with all the ACs running.
Be safe and healthy...stay cool in summer and warm in winter.
2002 Tiffin Phaeton
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Two Jayhawks
lenexa ks
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jauguston wrote:If you have to worry about the cost of using your AC it may be the RV lifestyle is not for you.
Jim
That is awesome! When I read pearls like this I can hardly believe it comes at no charge to us. Thanks for mingling with us little people.
2002 Safari Zanzibar
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bluwtr49
Green Valley, AZ
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Last year, on the way home through NV, I was running the dash air and out of curiosity I shut it of for 30 minultes to see if the fuel economy changed. We were running along at 62 straight and level on CC at 9.1 mpg and shutting of the dash air didn't do a thing....still sat at 9.1.
This was on the Silverleaf which is dead accurate and is a rolling average over ~30 seconds between updates.
It may make a differance though depending on the coach engine but on this big old CAT a few HP on way or the other isn't noticable.
Dick
2000 40" DP Beaver Patriot Thunder Cat C-12 425 HP, 1550 Tq
1997 Jeep GC Limited ---toad
2008 Toyota Tundra Crew Max Limited TRD (Retired)
2009 Cougar 268 RLS ~8700 lbs road wt (Retrired)
2006 Jeep Liberty Turbo Diesel.....TV in Training
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