How many miles on your RV? If it is less than 12,000 (20,000 k) you may be in for a pleasant surprise. Mileage may improve at that point.
Do you get better mileage with the dash air off?
I've not done accurate measurements--but on my first major trip mileage did not seem to be different from running with or without the AC on.
In my unit the dash air does little to cool the rest of the RV.
The roof air power by a generator will use fuel. Probably the end result would be more over all fuel consumption.
I can run my roof air from my engine alternator because of modifications I've made to the RV. If you wish to peruse them surf here:http://freecampsites.net/forum/technology/page-1/
and click on "solar boondocking"
QUOTE(DavyD @ Sep 3 2009, 08:49 AM)
I am curious what everyone's opinion is relative to running air condiioning systems while on the road in my motorhome.
I have a 2007, 30 foot Class C Motorhome with a Ford 6.8 liter V-10 engine. I averaged just under 8 miles per gallon for the past year while usually running the chassis air conditioning system.
Would I be better off running the generator/coach air conditioning to improve mileage?
Thanks in advance,