Cooling the back of the RV while driving

[randomguy]

Originally Posted by nctox

Hey! Let's get our priorities straight here. That wine has to stay cool.
Run the genny.

This right here is what convinced me. Running the generator it is.

[Thor29.3inAZ]

Pretty much anything over 100"F outside temps, we have difficulty keeping the inside under 90'F. It seems like most have more than one AC unit and that might make a difference. I did have the dealer go through the ducting to make sure all were sealed. We do start early to keep things cool but it catches up with us as the temps get higher. One of our travels thru Needles, CA was 122"F outside and we had a tough time keeping the inside under 100'F. With a gas engine class A and the unit being a 15000 btu, we thought it would be enough. I guess the next step is to install a second 15000 btu AC unit in the back. But that means we will have to make sure the chassis can except a 50 amp circuit and a bigger Onan..... That won't be cheap.......

[jonesdg]

Run the generator. All of your equipment is healthier when used. If you don't run the generator you will just start having trouble. Keep the rig cool. When you park and set up you will want to come back in to a cool rig. God bless and safe travels 😎😎😎

[Crasher]

Originally Posted by Thor29.3inAZ

Pretty much anything over 100"F outside temps, we have difficulty keeping the inside under 90'F. It seems like most have more than one AC unit and that might make a difference. I did have the dealer go through the ducting to make sure all were sealed. We do start early to keep things cool but it catches up with us as the temps get higher. One of our travels thru Needles, CA was 122"F outside and we had a tough time keeping the inside under 100'F. With a gas engine class A and the unit being a 15000 btu, we thought it would be enough. I guess the next step is to install a second 15000 btu AC unit in the back. But that means we will have to make sure the chassis can except a 50 amp circuit and a bigger Onan..... That won't be cheap.......

You might improve the cooling effect if you were to insulate the upper part of the front cap. Most companies do not put much insulation up there. It wouldn't cost you much more than your time. Bet you would notice the difference.

[George Schweikle]

We have not insulated the front cap, but use these in the roof vent recesses. https://smile.amazon.com/Trailer-Cam...vent+insulator
Also, place aluminum bubble wrap in the skylight over the shower.

Originally Posted by Crasher

You might improve the cooling effect if you were to insulate the upper part of the front cap. Most companies do not put much insulation up there. It wouldn't cost you much more than your time. Bet you would notice the difference.

[JC2]

Originally Posted by rayzor

When driving in these 90-100+ days, I pretty much have to run the generator full time to run the AC in the back to keep the MIL and kids cool. Not to mention the wine.

Is there a way to keep it cool back there without running the generator? We close all of the blinds, have tried the ceiling vent fan, crank the front AC up to 4 and point it straight down the middle.

I was thinking of getting driver/passenger fans, but those only would seem to benefit those up front. We tried a fan in the back and it helps if it isn't direct sun, or at about 85 degrees, but MIL starts complaining after that.

Here are the steps we pretty much use when we travel in our mh:
1. Start the generator approx. (2) hrs before leaving and turn on the "residential fridge". It will/ should be at/close to operating temp in that time frame. A rv fridge will need to be turned on 18/24 hrs before leaving on the average and can run off the batteries or inverter if their in good condition.
2. We then turn on the front roof air, set the fan to run on high instead of auto and set the thermostat temp to 70. If you have a 2nd roof air, you can repeat the same steps if/ when the outside temps go up noticeably later in the day. We've found that putting the roof ac fan in manual high mode will keep the inside coach air circulation more constant and comfortable throughout. When you arrive at your stop, then the ac fan(s) can be switch back to auto mode if desired. We have found that after stopping and outside temps are in the upper 80's-90's, we will sometimes leave one of roof ac fan(s) in manual mode and switch the other to auto mode for improving air circulation. Might want to experiment with this at your leisure as the fan noise might be objectionable.
3. When using our dash air, we will run it in max-cool mode 99% of the time which I've found works much better to cool the front 6-10 feet of the coach than regular ac mode does.(Brings in outside air which has to then be cooled)
4. Lastly, I will use the windshield overhead fans(defroster assist) in low fan speed mode on occasion to help further circulate the air. Some are more noisy than others so your call on this.
5. Pay close attention to your ac filter(s) and keep them clean.

Hope some this info is helpful.

[triplewide]

Originally Posted by Thor29.3inAZ

Pretty much anything over 100"F outside temps, we have difficulty keeping the inside under 90'F. It seems like most have more than one AC unit and that might make a difference. I did have the dealer go through the ducting to make sure all were sealed. We do start early to keep things cool but it catches up with us as the temps get higher. One of our travels thru Needles, CA was 122"F outside and we had a tough time keeping the inside under 100'F. With a gas engine class A and the unit being a 15000 btu, we thought it would be enough. I guess the next step is to install a second 15000 btu AC unit in the back. But that means we will have to make sure the chassis can except a 50 amp circuit and a bigger Onan..... That won't be cheap.......

We experienced the same issues with our coach. We tried most of the suggestions we found on IRV2 to help cooling with some effect but still cooling was lacking.

Looked at changing out generator to 5.5 KW from 4 KW, but do not think it will fit in the current gen location. Also a very pricey alternative.

Eventually added a second 11K BTU AC "Power Saver" to the rear. The 4 KW gen set runs both AC's with out issue as long as no other 120 volt loads are on. Water heater and frig on gas. No microwave, etc.

Have not been in 100+ temps yet since adding AC. But so far so good. At 122 degrees we would probably be doing good to have interior in the 90's with both AC's and dash air on.

Top 3 of 50+ mods I have done so far:

1. Insulating underside of cockpit floor and doghouse - major noise/heat reduction

2. Adding rear track bar - major handling improvement

3. Adding second AC - major comfort improvement

[triplewide]

Originally Posted by rayzor

When driving in these 90-100+ days, I pretty much have to run the generator full time to run the AC in the back to keep the MIL and kids cool. Not to mention the wine.

Is there a way to keep it cool back there without running the generator? We close all of the blinds, have tried the ceiling vent fan, crank the front AC up to 4 and point it straight down the middle.

I was thinking of getting driver/passenger fans, but those only would seem to benefit those up front. We tried a fan in the back and it helps if it isn't direct sun, or at about 85 degrees, but MIL starts complaining after that.

IMHO:

1. Run the genny -wear and tear $.10/hour

2. Run the genny - fuel cost: $1.25/hour

2. Cold wine and happy MIL and kids: PRICELESS

[Sweetbriar]

During the high heat of summer I cover the bedroom windows, roof vents and shower skylight with reflective insulation. Helps keep the heat down in the rear of the coach and darkens the room for late morning sleeping. Works for the colder times of the year to retain heat. I have sheets of it for the front windows in the living area but haven't use them as yet for summer cooling but have for winter heating. Also have a sheet up inside the top of the front cap.

As other's have mentioned you need to stay ahead of the heat curve. Everything in the coach needs to be cooled down. Floor, walls, ceiling, furniture and such before you'll notice the effect. Start early with cooling even if it means dropping the thermostat temp below your normal daytime temp setting prior to departure. I'm a Glamper not a camper and will use every feature of the coach to maximize my comfort, well actually the Navigator's comfort, when out on the road.

[OldDoggy]

We run the genny and keep it cool with our roof AC when the heats up outside. I have not really noticed a mileage slip with it on or off when motoring.

[bruceisla]

Originally Posted by Thor29.3inAZ

Pretty much anything over 100"F outside temps, we have difficulty keeping the inside under 90'F. It seems like most have more than one AC unit and that might make a difference. I did have the dealer go through the ducting to make sure all were sealed. We do start early to keep things cool but it catches up with us as the temps get higher. One of our travels thru Needles, CA was 122"F outside and we had a tough time keeping the inside under 100'F. With a gas engine class A and the unit being a 15000 btu, we thought it would be enough. I guess the next step is to install a second 15000 btu AC unit in the back. But that means we will have to make sure the chassis can except a 50 amp circuit and a bigger Onan..... That won't be cheap.......

It's cheaper to change your route

[Murf2u]

Originally Posted by rayzor

Is there a way to keep it cool back there without running the generator? We close all of the blinds, have tried the ceiling vent fan, crank the front AC up to 4 and point it straight down the middle.

Pointing the A/C down the middle doesn't do much unless you open the rearmost roof vent to create a vacuum and pull the cold air down the back and the hot air out.

The weakest part of the chassis A/C is the fan, it just doesn't move the volume of air required to fully exploit its cooling capacity.

[offtosleep]

Originally Posted by JC2

Here are the steps we pretty much use when we travel in our mh:
1. Start the generator approx. (2) hrs before leaving and turn on the "residential fridge". It will/ should be at/close to operating temp in that time frame. A rv fridge will need to be turned on 18/24 hrs before leaving on the average and can run off the batteries or inverter if their in good condition.
2. We then turn on the front roof air, set the fan to run on high instead of auto and set the thermostat temp to 70. If you have a 2nd roof air, you can repeat the same steps if/ when the outside temps go up noticeably later in the day. We've found that putting the roof ac fan in manual high mode will keep the inside coach air circulation more constant and comfortable throughout. When you arrive at your stop, then the ac fan(s) can be switch back to auto mode if desired. We have found that after stopping and outside temps are in the upper 80's-90's, we will sometimes leave one of roof ac fan(s) in manual mode and switch the other to auto mode for improving air circulation. Might want to experiment with this at your leisure as the fan noise might be objectionable.
3. When using our dash air, we will run it in max-cool mode 99% of the time which I've found works much better to cool the front 6-10 feet of the coach than regular ac mode does.(Brings in outside air which has to then be cooled)
4. Lastly, I will use the windshield overhead fans(defroster assist) in low fan speed mode on occasion to help further circulate the air. Some are more noisy than others so your call on this.
5. Pay close attention to your ac filter(s) and keep them clean.

Hope some this info is helpful.

What he said.

[brokenrule]

We have a single roof 15BTU unit and run it off the gen set and use the dash air when it is 100 outside. We put a 120v fan on the floor just behind the dog house and aim it toward the rear. This keeps the dog cool - just as important as the beer or wine.

Once at the campground I put the 120v fan, on high, outside under the MH and aim it up at the engine/trans so the heat does not radiate into the MH. That helps a lot to avoid heating everything up inside. I'll let it run until sunset.