Keeping it cool?

[roostonu]

How do you keep the inside of a large class C cool while driving long distances in hot weather? I'm thinking the cab A/C isn't going to do much for the House. Do you run the generator and roof top A/C?

Just curious.

[pnichols]

The approach of leaving a rear vent open to help suck cool cab air throughout the motorhome would be unacceptable to us: We travel with all vents and windows closed and the cab A/C on "MAX AIR" so that the A/C doesn't bring outside air in - it only continuously recirculates air inside the motorhome.

The cab air conditioning is a lot more efficient at cooling this way (because the cab A/C is no longer having to continuously cool hot new outside air). But here's the big reason for why we do it this way - you don't get outside air continuously flowing through the motorhome from the front air intake (usually somewhere around the front fenders) and then on back to exit through an open vent in the rear ... WHICH MEANS ... the inside of the motorhome stays a lot more free of dust and dirt that otherwise would be carried in from the outside air. This also helps make the more efficient cab A/C cool the entire coach area even better. We use the same approach in our car to help keep it's interior cleaner longer.

On RV trips we also stop to shop, eat lunch, and dry camp off and on - so of course we're very generous about using the generator and rooftop AC to keep the interior of the motorhome cool as required when we're not traveling. We have even run both the rooftop air and idle the V10 for cab air when parked for a fast lunch cool-down if we have been out and about away from the motorhome walking or hiking in scorching temperatures.

[Expyinflight]

JaxDad wrote:

Expyinflight wrote:
Why sweat and be uncomfortable when traveling, and arriving at your destination???

In terms of cooling capacity the dash A/C in a Ford Class C is FAR more powerful than any rooftop unit is, its ability to move that cold air around is its shortcoming. Opening the rearmost roof vent solves that.

I’ve tried it both ways and my dash A/C will keep my coach as cool all the way to rear as the rooftop and generator can.

The dash A/C is also a LOT quieter than a rooftop unit.

No sweating involved.

Great....if that works for you. But I can assure you, on 100 plus degree days in the Arizona summer....leaving a roof vent open...not so much for us. As soon as you shut the engine off....the rear of the coach is going to heat up reeeeeealllly quick. No thanks. We run the gen and roof a/c non stop. Could care less if it uses a bit of extra fuel. We travel in cool comfort. 🙂

[greyhook]

We ran the rooftop A/C with the genny while going through Death Valley at 115 degrees. We also found that foil on some windows helped too.

[Dusty_R]

If the sun is shinning on your wind shield it will heat the glass and that heat will radiant back into the coach. So I run the cab air conditioner on defrost.

[JaxDad]

Expyinflight wrote:
Why sweat and be uncomfortable when traveling, and arriving at your destination???

In terms of cooling capacity the dash A/C in a Ford Class C is FAR more powerful than any rooftop unit is, its ability to move that cold air around is its shortcoming. Opening the rearmost roof vent solves that.

I’ve tried it both ways and my dash A/C will keep my coach as cool all the way to rear as the rooftop and generator can.

The dash A/C is also a LOT quieter than a rooftop unit.

No sweating involved.

[Expyinflight]

The generator and roof air conditioner need regular use and exercise to maintain their good and reliable running condition. Use them!!!! That's what they are there for.
In the overall grand scheme....the 1/2 gallon of fuel per hour used is cheap...cool...comfort. Why sweat and be uncomfortable when traveling, and arriving at your destination???

[PSW]

I agree with Desert Captain. The vehicle AC keeps the whole coach cool and I always just open the vent in the bathroom to create a little suction of the air towards the back. I do this frequently on 100+ days and it works fine going down the road. I can think of only once or twice when I have kicked on the roof air and generator. Those were exceptional days going full blast across the Southwest with temps way above 100.

Paul

[pianotuna]

Hi Phil,

I use the Magnum inverter which is wired to run the "whole house" to run the air conditioner in fan only mode.

I can use the inverter to run the roof air for some time, but I worry about damaging the alternator, so I observe a strict 20 minutes of run time (1/3 duty cycle, so 40 minutes OFF) and monitor the starter battery. If the starter battery "hits" 12.3 volts, then I turn off the loads.

If cooling is not needed I'll sometimes use the water heater on the electric setting.

pnichols wrote:

pianotuna wrote:
Hi,

I've had some success by running the roof air on fan only. This seems to help distribute the cab air to the rest of the RV.

On a hot day I will run the roof air via a generator for an hour before I stop.

Don ... just curious: How does one run the air conditioning system's circulation fan when going down the road without running the generator ... or are you assuming an inverter is involved and feeding the RV's air conditioner circuit breaker while driving?

[S1njin]

Desert Captain wrote:
If you crack open a rear vent, especially if you can run the fan on a low "air out" setting, or window in the back of your coach and run the dash AC on high {aim the vents straight back and not in the face of the passengers}, it will go a long way toward cooling the coach.

In all but the most extreme temps this often will be all that you need. On a large Class C, 32' + obviously this won't be as effective as one that is 32'or less but it can often eliminate the need to run the generator to feed the roof AC. Running your generator will work but is going take at least half a gallon an hour and often more than that which will hit your mileage/wallet.

:C

I agree 100%.

[pnichols]

pianotuna wrote:
Hi,

I've had some success by running the roof air on fan only. This seems to help distribute the cab air to the rest of the RV.

On a hot day I will run the roof air via a generator for an hour before I stop.

Don ... just curious: How does one run the air conditioning system's circulation fan when going down the road without running the generator ... or are you assuming an inverter is involved and feeding the RV's air conditioner circuit breaker while driving?

[pianotuna]

Hi,

I've had some success by running the roof air on fan only. This seems to help distribute the cab air to the rest of the RV.

On a hot day I will run the roof air via a generator for an hour before I stop.

[roostonu]

Thanks for the quick replies.

[Desert_Captain]

If you crack open a rear vent, especially if you can run the fan on a low "air out" setting, or window in the back of your coach and run the dash AC on high {aim the vents straight back and not in the face of the passengers}, it will go a long way toward cooling the coach.

In all but the most extreme temps this often will be all that you need. On a large Class C, 32' + obviously this won't be as effective as one that is 32'or less but it can often eliminate the need to run the generator to feed the roof AC. Running your generator will work but is going take at least half a gallon an hour and often more than that which will hit your mileage/wallet.

:C

[gbopp]

Start your generator and turn on the roof A/C while driving. It won't hurt anything.