How much AC is needed?

Above 25 foot in length, I have NEVER had a customer come back in 40 years and state I wasted their money on the 2nd AC I insisted they needed above 90 degree heat. I HAVE had customers complain about the single AC that could not keep their 25 foot and larger RV cold enough in 90 plus heat. As others stated, you NEED 50 amp service for 2 AC units. UNLESS, you have a factory installed 30 amp EMS system that uses 2 low amp Colemans to run on 30 amp. Jayco uses such a system on certain 30 amp models. You need to look at RV's that come with 50 amp service. That way you can upgrade to a 2nd AC if needed without spending a lot of money adapting the electrical for that 2nd AC. Doug

BeerBrewer wrote:
I should have mentioned that the trailer manufacturer (Grand Design) claims that the trailer is well insulated. They state that it has R-40 in the roof, R-11 in the floor and R-9 in the walls in their brochure. The manufacturer also claims that the 15K BTU AC unit should work just fine and they have not gotten any complaints.

As for adding a second AC unit I was just curious and I was mainly interested in the actual AC unit install on the roof itself and all that goes with that, like sealing the roof and securing the AC unit its self. I wasn't that worried about the electrical aspect of the install and I don't mean to minimize that aspect of the install, its just that I'm an engineer and I've worked with electricity (AC and DC) my entire career, so I'm sure I could figure that out. All that said, I honestly don't think I'd ever do it. Seems rather crazy to plan on adding a second AC unit to brand new trailer. It would make more sense just to buy another trailer if the 15K BTU unit can't do the job.

You mentioned camping in summer in Texas and Florida. Not sure about Texas, but summer camping in Florida is hot and I'm very glad I had the dealer install the bedroom AC. It is most likely already wired for the AC. They offer two versions, one controlled by a thermostat which is more expensive, and one that just has the controls on the panel - no auto on/off.

wrgrs50s wrote:
From friends with 2 Acs, the positives are:

Use the bedroom Ac when watching television since the living AC is so loud, and use living room AC at night so the bedroom is quiet. Have them run your living room AC and turn on your TV, you will notice that that can be a problem.

If one goes out you have a backup. Ask someone who has had that happen.

Most important: Never bank on what a manufacturer or salesman tells you when they are attempting to make a sale. Do more research and you will find that even a lot of the higher end rigs have difficulty in maintaining a comfortable temp when the outside temps reach near 100.

. X2. Having 2 AC units is definitely a bonus for these reasons. On hot days we run both.

Short answer NO.

Suggestion: put a 2nd 15000 BTU on it. ceiling controls (if you can reach the ceiling) that way it only needs 120 volt. I like Coleman's here for other reasons (They suck which in this case is a good thing. makes the condenser easier to clean. most others blow Way more work).

Run a 12ga line to a handy spot inside where you can install a SINGLE BREAKER switch. (note they make 20 amp breakers that mount in a standard wall box) from there to a 20 amp inlet on teh "Services" side of the RV and a 20 amp cord to the parks' 20 amp outlet from there.. fully independent of RV it will be so it won't trip a GFCI like a cheater box would.

BeerBrewer wrote:
I should have mentioned that the trailer manufacturer (Grand Design) claims that the trailer is well insulated. They state that it has R-40 in the roof, R-11 in the floor and R-9 in the walls in their brochure. The manufacturer also claims that the 15K BTU AC unit should work just fine and they have not gotten any complaints.

As for adding a second AC unit I was just curious and I was mainly interested in the actual AC unit install on the roof itself and all that goes with that, like sealing the roof and securing the AC unit its self. I wasn't that worried about the electrical aspect of the install and I don't mean to minimize that aspect of the install, its just that I'm an engineer and I've worked with electricity (AC and DC) my entire career, so I'm sure I could figure that out. All that said, I honestly don't think I'd ever do it. Seems rather crazy to plan on adding a second AC unit to brand new trailer. It would make more sense just to buy another trailer if the 15K BTU unit can't do the job.

I'm an electrical engineer also on Long Island. The cost difference of doing it if you already have 50 amp service versus only having 30 amp currently is significant. That would be my only hesitation.

In Texas you will want a second A/C on that size RV. End of discussion.

From friends with 2 Acs, the positives are:

Use the bedroom Ac when watching television since the living AC is so loud, and use living room AC at night so the bedroom is quiet. Have them run your living room AC and turn on your TV, you will notice that that can be a problem.

If one goes out you have a backup. Ask someone who has had that happen.

Most important: Never bank on what a manufacturer or salesman tells you when they are attempting to make a sale. Do more research and you will find that even a lot of the higher end rigs have difficulty in maintaining a comfortable temp when the outside temps reach near 100.

You will not be unhappy with too much but will be unhappy with too little.

I should have mentioned that the trailer manufacturer (Grand Design) claims that the trailer is well insulated. They state that it has R-40 in the roof, R-11 in the floor and R-9 in the walls in their brochure. The manufacturer also claims that the 15K BTU AC unit should work just fine and they have not gotten any complaints.

As for adding a second AC unit I was just curious and I was mainly interested in the actual AC unit install on the roof itself and all that goes with that, like sealing the roof and securing the AC unit its self. I wasn't that worried about the electrical aspect of the install and I don't mean to minimize that aspect of the install, its just that I'm an engineer and I've worked with electricity (AC and DC) my entire career, so I'm sure I could figure that out. All that said, I honestly don't think I'd ever do it. Seems rather crazy to plan on adding a second AC unit to brand new trailer. It would make more sense just to buy another trailer if the 15K BTU unit can't do the job.

I'll throw in that some makes of ACs work better than others so it depends.