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Do you run house AC while on the road

Jframpey
Explorer
Explorer
I am contemplating the purchase of a motor home... class A or Super C. I currently pull a 31’ trailer and am looking to consolidate the living and driving into 1 vehicle, adding conveniences like auto leveling, larger holding tanks, boondocking with solar or generator.

One question I haven’t heard answered so far is: When on the road does the engine powered AC provide sufficient cooling for the entire coach? (I’m looking at 30 - 35’ coaches) or do you run the generator and the coach AC’s?

For simplicity I live in the southeast US and will be traveling in the summer (90’s with lots of humidity).

A related question - while winter traveling is the engine heater sufficient to warm the coach, say down to 35?

Please enlighten me.

Joe
45 REPLIES 45

Sandia_Man
Explorer II
Explorer II
Just like with our 33' toy hauler TT, we run our rooftop AC via Onan genny to keep rig cool while traversing down the road, nothing like arriving to your destination with a pre-cooled rig. In our class A as weather conditions dictate we certainly run our AC units via genny without ever considering costs compared to comfort, if you are not bedding down in a tent or truck bed you are glamping.

Pretty simple really, just do what works for you. Forget fretting about putting hours on your genny, Onans simply love to run and often times issues begin with their stagnation from lack of use. As for fuel costs, I pay more for a cup of coffee than having onboard Onan power our entire rig for a few hours, why have all the amenities an RV provides if you can't use them whenever and wherever.

JC2
Explorer
Explorer
The below list explains when/how we have used the dash ac, coach ac, generator in our mh's.


1. When initially leaving, outside air temps determine if the dash air is turned on.
2. If needed, "always" set dash ac on Maxcool and fan speed of low, med or high.
3. Additionally, most mh's will usually have (2) fans above the windshield which usually are intended for defrosting if needed but we've found these help circulate the ac air when turned on low or med. High seemed to be a little to noisy.
4. When/if outside start going upwards,(90+) we will then turn on the generator and the front roof air to start assisting the dash air. The roof air stat is set to 70 degrees and the fan speed to manual high. Compressor will kick on/off as needed while the fan continually circulates the air throughout the coach. Whe will also use the described fan speed method for the roof air(s) when we are stationary at a park and the outside air is in the 90s. They are made to run; use them.
5. We have occasionally had to turn on a second roof air when traveling if the outside air continue rising upward. Nothing like arriving at your destination in a pre-cooled coach.
6. Fuel usage for us has been usually in the 1/2-3/4 gal range per hour with diesel generators.
7. Our yrly hr usage will regularly be 250-300hrs.
2010 Newmar Dutch Aire 4304,Cummins ISL 425hp,Spartan MM Chassis,2013 Chev Equinox AWD Towed,Ready Brute Elite TowBar/Brake,FMCA #402879,SKP#120487

Ro_n_Joe
Explorer
Explorer
Currently in eastern US where we haven't boondocked much. Ran the AC last week and put the thermostat down to 67 to run a couple of our ACs to exercise the generator. Did it again 1.5 months ago. I emagine we'll run them during the hot days when travelling this summer.
2020 Dutch Star 4328 on FL Chassis
2018 Grand Cherokee Limited
Ready Brute Elite Towbar & Road Master Wiring

dodge_guy
Explorer
Explorer
After traveling for 15 years with a TT in the summer and getting to a destination having the trailer interior at 90+ degrees and taking a couple hours to cool everything down, I’ll gladly run the generator to keep it comfortable for when we get to our destination! Well worth the extra $10 dollars or so a day it costs to run it.
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

Monkeyman_and_L
Explorer
Explorer
Depends. If there's no one in the rear area and the temps are staying comfortable then we don't. I leave the middle door closed and only run the front zone when we travel though.

Our class A has an auxiliary heater that is a huge heater coil in the bedroom area with a fan. When we travelled in the spring overnight we ended up learning what that switch does. Kept the coach warm without running the generator.
Monkeyman, Lady and little chimp
2018 Newmar Baystar 3414
2022 Ford Escape Hybrid TOAD

Jframpey
Explorer
Explorer
Yup, forgot to convert 120 volts to 12 volts - I’ll just suck it up and run the generator

Cocky_Camper
Explorer
Explorer
I live just south of you across the state line. The answer is yes! We have to run it to keep our 35ft class A cool. The window asks like a huge oven and the front A/C never stands a chance, even with a curtain placed just behind the front seats.
2004 Sea Breeze by National RV - 8341

Former Coaches:
2006 Keystone Zeppeline 291 - TT
2000 Aerolite Cub F21 - Hybrid TT
1991 Coleman Pop Up

Formerly known as: hybrid_camper

dodge_guy
Explorer
Explorer
1 AC unit will pull 9 amps when running, startup it pulls 20 amps. a soft start kit would alleviate that issue, but running AC off of an inverter and batteries would require at least $15k in equipment. the thought is great, but Ill just run the generator!
Wife Kim
Son Brandon 17yrs
Daughter Marissa 16yrs
Dog Bailey

12 Forest River Georgetown 350TS Hellwig sway bars, BlueOx TrueCenter stabilizer

13 Ford Explorer Roadmaster Stowmaster 5000, VIP Tow>
A bad day camping is
better than a good day at work!

DrewE
Explorer
Explorer
Jframpey wrote:
Some of these rigs have big inverters, battery banks and solar... does anyone try to use an inverter to power the AC - and pull power from an alternator? And solar?

I guess anything is possible, but practical? Each AC would be 1500 watts - 15 amps running. That doesn’t seem like a big load to add to an alternator.

I’m not worried about fuel use, just hrs of generator use.


That's 15A (or a bit less) at 120V; the load on the alternator would be closer to 150A (assuming a 12V system; half that if you happen to have a 24V system). It's definitely a big load to add to most alternators. That being said, it might be practical on some rigs, at least for a single roof air conditioner. (You'd have to make sure the battery combiner/isolator circuitry and wiring is up to the job, besides just the alternator itself).

way2roll
Nomad III
Nomad III
Jframpey wrote:
Some of these rigs have big inverters, battery banks and solar... does anyone try to use an inverter to power the AC - and pull power from an alternator? And solar?

I guess anything is possible, but practical? Each AC would be 1500 watts - 15 amps running. That doesn’t seem like a big load to add to an alternator.

I’m not worried about fuel use, just hrs of generator use.


I think Mr. Mark once said he had his Prevost built with a massive Li Ion battery bank large enough to run his AC. Like 24 batteries or something. If I recall the cost was about $10k for the batteries.
2023 FR Sunseeker 2400B MBS

Jframpey
Explorer
Explorer
Some of these rigs have big inverters, battery banks and solar... does anyone try to use an inverter to power the AC - and pull power from an alternator? And solar?

I guess anything is possible, but practical? Each AC would be 1500 watts - 15 amps running. That doesn’t seem like a big load to add to an alternator.

I’m not worried about fuel use, just hrs of generator use.

Larrysr1957
Explorer
Explorer
Yes we run the generator so the passengers can see television and the a/c’s are running.

chuckftboy
Explorer
Explorer
For Memorial Day weekend I traveled from north Florida to central Florida and back during the heat of the day, 90 plus. Just me and the wife, we only used dash air and were quite comfortable sitting up front. It got warm in the back but we never felt it up front. If had passengers the roof a/c's would have been on
2019 Horizon 42Q Maxum Chassis w/tag
Cummins L-9 450 HP / Allison 3000
2006 Jeep TJ and 2011 Chevy Traverse Tows

DC_MC
Explorer II
Explorer II
If we are driving while it’s hot we get up and go really early. Even running the roof air doesn’t get forward enough to help the driver much. We also put a large fan in the hallway blowing forward to help the AC get forward
2006 Mandalay 40E motorcoach
2017 Ram PU
2017 Harley Road King
Home base Yuma AZ