Hot in the South

[Bama Fan]

Has anyone ever had an additional ac unit installed in a Precept 35S? If so, did you have to have a layout showing where the ac ducts were located? I own a 2017 model and have been places where the ac units struggle to keep up. Actually, while in Arizona, had to leave the slides in until dusk. OR, does anyone know of a better way to get additional cooling?

[Foretm]

Never have added a second unit, but do have a few questions and suggestions. Is your unit a 15K BTU unit? Have you pulled your inside cover and made sure your unit is sealed properly and your ducting is taped good to maximize the efficiency of the unit? If not, I highly recommend starting there and then look into RV Airflow. This unit is designed to channel cold air to the ducting in a more efficient manner and can help the efficiency of your unit. Do you have something to shade the windows to keep the heat out in the first place? Magnashades or something similar? Best cure is prevention.

If you did all of that and you still cant keep it cool, I would then research by contacting Jayco to see if your RV was structurally deisgned for a second AC. Ask for the roof schematics, they'll need your VIN. Also consider a portable room AC for those times when you do camp in the heat.

[Bama Fan]

Yes, I have done all of the above. I have two units in the precept 35s; one is a 15,000 BTU and the other a 13,000 BTU. Spoke with a jayco rep yesterday who advised the 15,000 BTU unit is designed to cool to approximately 30 degrees below outside temp and the 13,000 BTU is designed to cool approximately 20-25 degrees below the outside temp, which is about what they’re doing. Thinking of adding a third unit (which I’m seeing more of on larger coaches) for areas with extreme heat. Rep said they could not recommend after market units or installation, but is supposed to be sending me the roof plan. Thanks for responding.

[norty1]

Have you looked into the portable units with an exhaust pipe? I have read about them used to cool in rv’s

[Foretm]

ok gotcha... sorry i'm not familiar with the 35s. I guess you could always swap out the 13 for a 15. In that case, i think the issue you're going to face is the lack of structural roof openings for an AC. I've attached my roof schematic, but you can see that the roof is only structurally designed for 2 ACs. If you try to put a 3rd, you'll need a place that has the 14" cutout and structural members to handle it.


I think looking for a portable AC that you can put in and out would be the best option.

[Bama Fan]

Good advice. Thanks again

[Grumpy]

Originally Posted by Bama Fan

Yes, I have done all of the above. I have two units in the precept 35s; one is a 15,000 BTU and the other a 13,000 BTU. Spoke with a jayco rep yesterday who advised the 15,000 BTU unit is designed to cool to approximately 30 degrees below outside temp and the 13,000 BTU is designed to cool approximately 20-25 degrees below the outside temp, which is about what they’re doing. Thinking of adding a third unit (which I’m seeing more of on larger coaches) for areas with extreme heat. Rep said they could not recommend after market units or installation, but is supposed to be sending me the roof plan. Thanks for responding.

Somebody is handing you a line. An air conditioner will only drop the ambient air temp by 15 to 20 degrees across the coil and that even applies to a house unit and RV units are not as efficient. There is no correlation between outside and inside temps.

How much can an air conditioner drop the temperature in your home? Air conditioners are designed to lower the temperature of your home's air by about 20 degrees. So if the air in your home is 85 degrees, for example, your air conditioner can lower your air's temperature to about 65 degrees.

[Bama Fan]

Originally Posted by Grumpy

Somebody is handing you a line. An air conditioner will only drop the ambient air temp by 15 to 20 degrees across the coil and that even applies to a house unit and RV units are not as efficient. There is no correlation between outside and inside temps.

How much can an air conditioner drop the temperature in your home? Air conditioners are designed to lower the temperature of your home's air by about 20 degrees. So if the air in your home is 85 degrees, for example, your air conditioner can lower your air's temperature to about 65 degrees.

That’s for the info. Much appreciated.

[RogerR]

Instead of adding more AC capacity consider using Reflectix foil covered bubble wrap. Designed for wrapping around AC ducts to insulate them it also works very well to reflect heat from coming in windows. I bought it to prevent fading during storage (works well for that) but found it's insulation properties also worked well in cold weather in Sept. in the Rockies and very hot weather, Arches in July.

Window film may also help with both cold and heat but Reflectix works for us.

If you do want more AC capacity and are thinking of a portable go with a 2 hose model. The single ones draw inside air and use it to cool more inside are. This pulls in air from outside somewhere else which just isn't practical in an RV

[Bama Fan]

Thanks, it’s definitely worth considering.

[Mike-NM]

Are you using anything to keep the heat out from the windshield? I live in a hot climate and travel to AZ often in the summer. Tombstone AZ is hot and without covering the windshield with reflective insulation my two AC's struggle. Once I put up the insulation windshield, driver and passenger side windows it is a world of difference and the AC's do the trick.

[Bama Fan]

That was on my list. All of my windows are dark tinted, except for the windshield. They also have pull down solar screens as well as pull down shades, with the exclusion of pull down solar screens on the cab windows and windshield. Been looking at the magnetic screens which appears to be easy to install and remove. Thanks for your input.

[Foretm]

Yea, I mentioned prevention in my first response: "Do you have something to shade the windows to keep the heat out in the first place? Magnashades or something similar? Best cure is prevention." You said: "Yes, I have done all of the above", so I assumed you had some type of window shades and not the ones that come with the unit. Internal shades still allow the heat in (greenhouse effect) by heating the shade itself, you have to stop it before it comes in, so external shades/reflecting material are the best to make sure the heat never enters in the first place.


You can't imagine the difference an external shade can provide on the windshield until you put one on. Its night and day difference, just make sure whatever you get block all or most of the UV rays. Magnashades are very good, expensive, but good. I have the ones for the windshield and cab windows.

[Bama Fan]

I had a snap-on solar screen on my previous coach and yes, it did work wonders. Was hoping to be traveling near an RV Rally Event, one day, and get a magnashade or something similar Installed on site. Thanks again

[Foretm]

Originally Posted by Bama Fan

Was hoping to be traveling near an RV Rally Event, one day, and get a magnashade or something similar Installed on site. Thanks again

Magnahades are custom made to order, and they will install at their facility if you make an appointment. Not sure where you're located, but they are in NC. They do seem to be at an event in Az in the near future, but you would need to check with them to see if they will install at an event. My guess would be no, but worth asking. The installation is not hard at all, I did mine myself with the help of my wife.

[Bama Fan]

I live LA (Lower Alabama). Just looked it up and they are approximately 600 miles from my location. Sounds like a good excuse for a road trip��. I’m definitely interested. Thanks for all the help.

[Foretm]

Big RV show in Tampa in January... I would buy now and make the trip to let them do it and/or check to see if they can do it in Tampa

[Bama Fan]

Awesome, thanks