Community Forums

flashfire198 · 05-19-2013, 03:39 PM

I have hear lots of conversation that its best to use generator air while driving to save gas but it gets hot driving so some say use the front engine air and it wont effect gas mileage...what do u think?

Tha_Rooster · 05-19-2013, 03:45 PM

On a hot summer day I have to run both it just depends on the weather.

Dennis_K · 05-19-2013, 03:52 PM

I always use the dash A/C until it won't keep up, then I fire up the Gen and turn on the House A/C. Whenever we are traveling where the temperature is over 85 I turn on the House A/C about an hour (or more) before we reach our destination so the House will be cooled off when we stop.

4Knights · 05-19-2013, 03:52 PM

I run the generator and both roof airs just to keep cool, not cold mind you just cool. My rig really heats up, can't imagine the dark colored coaches. I believe the newer models may have better insulation than my old pace arrow.

Medico · 05-19-2013, 03:54 PM

With my coach, when it's warm to hot, my dash AC is not enough to cool the whole coach. I have to run the roof AC. The hotter it is the more ACs I have to run, 1 or 2 or all 3. On a day between say 70 to 75, just the dash should be enough.

The roof ACs generally require the generator to be running as well.

phays · 05-19-2013, 05:44 PM

Well, running the generator will use fuel so the real question is, what is the trade-off between running the dash air and running the house air with the generator.

This subject has been discussed many times and I don't know that anyone has actually measured fuel used under both conditions to get a real answer.

At the speed I run, 60 mph, it takes my fuel mileage from 8 mpg down to 7.3 mpg based on Onan's literature claims of generator fuel usage. My dash a/c doesn't work so I can't run a test against the dash air fuel usage. But, I like having the whole house cooled.

MSHappyCampers · 05-19-2013, 05:50 PM

To heck with the fuel! When I'm hot I'm gonna run the genny and both air conditioners!

When we took a trip out west last spring we frequently had to run them! It got hot out there in the desert pretty early in the year!

jzick · 05-19-2013, 05:51 PM

Quote:

Well, running the generator will use fuel so the real question is, what is the trade-off between running the dash air and running the house air with the generator.

To DW and I, there is no trade off to consider. We believe that comfort trumps all other considerations. We run the genny with roof AC, and the dash AC, adjust both as necessary for comfort, and enjoy our trip.

vsheetz · 05-19-2013, 06:07 PM

Some coaches the dash air works better than others, so not one set answer.

Current coach the dash air works pretty well, so seldom use the roof air while driving. A previous coach the dash air was left off and the roof air nearly always used.

PyrateSilly · 05-20-2013, 08:28 AM

We use dash most of the time. We also plan any hour or more stops for during the hottest part of the day to miss running down the road with the hottest temps. It just happens that at about that time is when we need to get out and stretch anyway. Thom is not retired so don't have the luxury of only traveling 200 miles or less. As a matter of fact we are taking off on a trip either this morning or tomorrow morning (depends on how fast we get started on putting things away) and going from SoCal to FL, AL and back to SoCal all within 2 weeks. So yea I see us putting the genny on and running the AC at some point, lol.

RickO · 05-20-2013, 08:56 AM

Hi and welcome to the forum.

We're lucky in that our dash air works really well. In >50000 miles, we've only had to run the genny while traveling a couple of times in order to stay cool enough.

I sure wouldn't base my decision on which to use on fuel economy. I doubt there's enough difference to matter much.

Good luck.

Rick

Skip426 · 05-20-2013, 09:22 AM

Quote:

Originally Posted by flashfire198

I have hear lots of conversation that its best to use generator air while driving to save gas but it gets hot driving so some say use the front engine air and it wont effect gas mileage...what do u think?

Your dash A/C compressor will require 11>15 HP to operate , altough slight; by M/H standards; there is a penalty ; fuel use ; involved. Most gen sets will use .5to .7 gal per hour. So as others have said ; what price do you put on comfort; if it's too hot to drive comfortably , what would you do , stop and run the gen set to cool the coach ? find a RV park and pay for the power and spend another day on the road ? Your spending money no matter what you do . Might as well do what you want.

Iangolf · 05-20-2013, 07:33 PM

We like it cool in the rv so we run the generator with both roof units and the dash air. When we went to FL for spring break we ran the front roof unit on auto/cool and the rear unit was set to fan only since outside temp was not that high. Also, the dash air was on for me since I am the one sitting in the big glass fishbowl.

Fl_Richard · 05-23-2013, 08:09 AM

Quote:

Originally Posted by phays

Well, running the generator will use fuel so the real question is, what is the trade-off between running the dash air and running the house air with the generator.

This subject has been discussed many times and I don't know that anyone has actually measured fuel used under both conditions to get a real answer.

At the speed I run, 60 mph, it takes my fuel mileage from 8 mpg down to 7.3 mpg based on Onan's literature claims of generator fuel usage. My dash a/c doesn't work so I can't run a test against the dash air fuel usage. But, I like having the whole house cooled.

So at 60MPH in an hour you'll use 7.5 GPH with no genny and with the genny you'll use 8.2 GPH. That's roughy .75 gal per hr.

Mythbusters found using the air conditioner decreases fuel efficiency using the compressor by about 10 percent.

At your 8mpg this means that using the dash AC uses about .8 gph. Given the generator can produce a better cooling effect then the dash unit it would seem logical that as they both use approx the same amount of fuel using the House AC you will get more cooling BTU's per hour than than using the dash on roughly the same amount of fuel.

Looks like a wash as far as fuel is concerned, however if you want to stay cool the house ac and generator seem to be the way to go.

However after adding the additional genny maintenance for the additional hours used it's probably cheaper overall to use the dash.

Clear as mud eh?