Keeping Cool

[bdpreece]

For many years and through several class A gas motorhomes with gas generators, I have always subscribed to the theory that it was cheaper to leave the dash air off and run the roof air via the generator. Now since I have a diesel engine and also a diesel generator I am not certain which is the most economical way to keep cool. Has anyone actually done any comparisons?

[Cruzer]

The genset powered roof air units have more BTUs than the dash air and will keep the entire coach evenly cooled off with minimal fuel usage. Generators need to be run often, rather than left sitting, so it's worthwhile to run it when driving in warm temperatures to give it some exercise.

[wnytaxman]

I agree with Cruzer that it's best to run the roof air units to keep the coach cool. We were in Branson last summer and we tried just running the dash A/C and blowing the colder air into the coach with the defrost fans. We froze up front and they were roasting in the back. Crank up the generator and turn on the coach A/C and everyone was happy.

[bdpreece]

Since there is only two of us and the dash air keeps us very comfortable I am just looking for the most economical way to keep cool. I know that the gen set needs to be used but not for 4 to 6 hours or more every day.

[ga traveler]

I talked with rep.s at all the dealer shows that I went to. They all said the dash air was the cheapest way to go. However if there are more than just two people up front you need to run the generator to cool the people in back. Also all the dash A/C people said it was important to run the dash A/C about 15 min. every month to keep the seals lubed and soft.

[hooverbill]

Quote:

Originally Posted by bdpreece For many years and through several class A gas motorhomes with gas generators, I have always subscribed to the theory that it was cheaper to leave the dash air off and run the roof air via the generator. Now since I have a diesel engine and also a diesel generator I am not certain which is the most economical way to keep cool. Has anyone actually done any comparisons?

I can't believe that your ISL would even know the A/C was on. What is a small compressor to a turbo diesel with 1,200 ft/lbs of torque?

[bdpreece]

Quote:

Originally Posted by hooverbill I can't believe that your ISL would even know the A/C was on. What is a small compressor to a turbo diesel with 1,200 ft/lbs of torque?

My thought exactly. I was just wondering if anyone has any supporting evidence/experience .

[JimM68]

My old pace arrow gassser's dash air would keep the whole coach reasonably cool. We never ran with the gennie and roof air's on.

The Knight will not. The dash air is no where near as effective as the Fords. With our front kitchen layout, "other passengers" are generally much further back in the coach. The big slide, when closed, close up the cockpit pretty effectively, the back gets hot. Genny and roof air is a must when people beside me and the DW are aboard.

[powerboatr]

Quote:

Originally Posted by bdpreece My thought exactly. I was just wondering if anyone has any supporting evidence/experience .

i find if its 80-85 outside the dash a/c will keep us comfortable
however the rear bedroom gets pretty warm from the hunk of hot iron under it.
soooooooo
i will run the genny and both a/cs' about 1 hr out of our destination to cool off the coach.

if its hotter than 85 and i get slightest bit warm, i will run the front a/c and dash unit.

then turn off the dash unit after the roof top cools me down.
i have also turned both front vents on the ceiling to blow air at me while driving
i like to be able to hang chickens in the coach, so we keep it pretty cool

mpg wise????? i couldn't tell you

[Southernboy]

We usually just run dash air only two of us

[Cat320]

Quote:

Originally Posted by powerboatr i will run the genny and both a/cs' about 1 hr out of our destination to cool off the coach.

Good idea.

[Gary RVRoamer]

A compressor takes horsepower to run, so whether driven by a big diesel or a small one (the genset), the horsepower needed is an extra load, consuming extra fuel.

That said, I can't reliably detect any difference in fuel consumption on my ISL when the dash air runs. It's somewhere in the tenths of a gallon per hour and gets lost in the rounding. The genset is similar in fuel cost - I can run one a/c for a cost of less than 0.3 gal/hr (according to Onan) - and I get more cooling. I can run both front and rear a/c for about 0.5 gal/hr.

[Diplomat Don]

bdpreece.......We run the dash A/C and use a clear plastic shower curtain on a spring rod and place it right behind the driver/passenger seat. It fits against our slide and the passenger wall with about 6" from the top of the curtain to the roof. The split in the curtain allows my wife to access the rear of the coach. I also turn on the fantastic fan in the center of the coach to exhaust the hot air that rises over the top of the curtain. This seems to work fairly well for us. When we reach our destination, we turn on the generator and the roof air while we're checking in and parking the coach.

[Wizard]

Obviously none of you ride with my DW. Its always both and sometimes I need a jacket.