How to cool RV while driving

[Murf2u]

Originally Posted by NHRA225

Shut the Cab A/C off and run the Genny !

You can't make a blanket statement like that. In a larger Class A it might make sense, but for those of us with a Class C on a Ford or Sprinter chassis in particular, it makes no sense at all.

My dash a/c is a 60k. BTU unit, why would I turn it off so I can burn more gas to run a 15k. rooftop unit?

[olustee bus]

Thanks Murf, I will try that.

[DogNPonyshow]

Murf2 I drive a 29 foot Class C...running my house AC makes total sense for the well being of my dogs since the chasis AC alone cant keep their area which is directly behind the passenger seat, cool enough when the exterior temp is over 80. I also use refletix in all the house windows and sky light and vents.

[Murf2u]

That's strange, although my unit is a few feet shorter, I have no problem keeping the rear portion cool in weather well into the 90's while travelling.

My dogs like to lie on the rear corner bed and they're plenty cool back there

[DogNPonyshow]

Your chasis AC must have a better blower than mine. Mine cant keep up . My dogs are heavily coated and there are 6 crated for everyone's safety. I fun fans on each crate to ensure good air circulation for them, and a sweater for me since Im.more comfortable at 80 😀

[96 Wideglide]

Originally Posted by Murf2u

You can't make a blanket statement like that. In a larger Class A it might make sense, but for those of us with a Class C on a Ford or Sprinter chassis in particular, it makes no sense at all.

My dash a/c is a 60k. BTU unit, why would I turn it off so I can burn more gas to run a 15k. rooftop unit?

Do you have anything to back that up?

I find it pretty hard to believe your dash air puts out the same BTU as 4 15K rooftop units !!

[JC2]

Just curious but do you have the dash air knob on your C set to the max cool mode? If not, try that as it does not bring in outside air but will continually re-cool the inside air of the rv. Also, if you know, what is the temperature of the air coming out of your dash vents when using the ac?

Originally Posted by DogNPonyshow

Your chasis AC must have a better blower than mine. Mine cant keep up . My dogs are heavily coated and there are 6 crated for everyone's safety. I fun fans on each crate to ensure good air circulation for them, and a sweater for me since Im.more comfortable at 80 ��

[DogNPonyshow]

Yes set to Max Air Mode, I dont know temp it comes out at, but if I blast it I freeze in the cab area but it cant keep up with main house if outside temp is much over 75. I shut my door that closes off bath/bed spaces from living/kitchen .

I have zero overall mpg difference driving at 60 mph running my Generator vs not so Dont mind running it.

[Murf2u]

Originally Posted by 96 Wideglide

Do you have anything to back that up?



I find it pretty hard to believe your dash air puts out the same BTU as 4 15K rooftop units !!

Science. It's setup for a 3.5 pound charge and runs a huge compressor.

BTW, a little Ford Focus has an 18,000 BTU a/c system. A typical SUV has a ~35k a/c system, slightly higher if it has a rear heat / a/c system too.

[Murf2u]

Originally Posted by DogNPonyshow

Yes set to Max Air Mode.......

And THAT is why you are freezing and the back of the coach is too warm.

Max a/c closes off the fresh air intake from the cowl vents and takes return air from the passenger foot well. This is forcing the cold air to stay in the cab area and there is nothing to push it down the back.

If instead, as was stated above, you leave the AC on normal and open the rearmost vent you will draw the air out of the cab area and into the back of the coach.


BTW, a typical 4K generator running an AC unit will consume approximately 1/2 to 3/4 of a gallon of gasoline per hour of running time.

If we're talking about a typical Class C that gets ~8 mpg then at 60 mph it's burning ~7.5 gallons per hour, therefore if you used another 0.75 gal / hour it would be a 10% increase in fuel mileage, not zero.

[DogNPonyshow]

I average 7.8 mpg at 65 mph Generator or no generator... I average 8.3 going 60...ive carefully compared and tracked over 50,000 miles . There is no appreciable difference.

Btw have also tried the vent no max ac trick...no appreciable temp difference there either. I keep a temp alert alarm set .

But thanks for all the interest and ideas! 😀

[Murf2u]

Originally Posted by DogNPonyshow

I average 7.8 mpg at 65 mph Generator or no generator... I average 8.3 going 60...ive carefully compared and tracked over 50,000 miles . There is no appreciable difference.

Btw have also tried the vent no max ac trick...no appreciable temp difference there either. I keep a temp alert alarm set .

But thanks for all the interest and ideas! 😀

I must say you're Motorhome is quite an anomaly.

My generator burns quite a bit of gas, not none, and the rear vent open keeps the back of my coach at least 10 deg. F. cooler. Same with everyone else I know.

[Mich F]

I usually run with the generator on and my roof air running, without the dash air running. I find that my dash air normally increases my engine temperature 5 or 6 degrees. I've read that the SAE says that running your dash air decreases gas mileage by 5-10%. The generator which uses around a 1/2 to 3/4 a gallon per hr., is much more efficient, at somewhere around the equivalent of 100 mpg.

[mel s]

Originally Posted by klschams

Hi everyone, I am new to this forum and new to RVing. I have a 2007 fleetwood Tioga, 26 ft. Can I run the air while driving? I did not need to before but, it is really getting hot now. They day 97 on Thurs and I will be on the road.

klschams
Yes you can.
You can run the dash air while driving... and if needed you can also run the roof air(s)... (but only if you have, and run, a generator).
Mel
'96 Safari