13,500 A/C not enough

[jkollar1]

Thought someone might be able to give a suggestion on what to do. Our 2010 Outback only has 2 ceiling vents in the bedroom for the a/c and on one outing where it got to 110 degrees the bedroom didn't get cooled a whole lot. There is no pre wiring for a second a/c unit and we have no vent fan either. Thinking maybe only solution is to buy a plug in fan and see how that works. Any advice would be appreciated since summer is around the corner, thanks.

[jq1031]

Hey Jim......my motor home (sold) had two 13.5 AC units. In LasVegas back on July 4th 2007 it was 117 degrees! Inside it never got below 85 inside for two or three days.......My new Laredo TT has one 15K unit & under the same circumstances it would be the same. The answer is when it's that hot outside the inside is usually & no more 20 degrees cooler.
Joe

[jkollar1]

Thanks jq1031 I appreciate the feedback, sounds like if at all possible try and stay out of the really hot weather.

[Bob Landry]

Hey Jim......my motor home (sold) had two 13.5 AC units. In LasVegas back on July 4th 2007 it was 117 degrees! Inside it never got below 85 inside for two or three days.......My new Laredo TT has one 15K unit & under the same circumstances it would be the same. The answer is when it's that hot outside the inside is usually & no more 20 degrees cooler.
Joe

The 20 degrees you are refering to is the difference between the discharge air temp and the return air being drawn across the evaporator, also known as Delta T or "split across the coil"

The relationship between the outside ambient temp and the inside temp is determined by the actual temperature, if you are under any shade, the R value of insulation in walls and ceiling, etc, but is not predetermined designed or predictable.

[joseph.feucht]

I had the same problem. Dealt with it for 3 months, then brought it back to the dealer and purchased a 5th wheel with two a/c units. I never could run the A/C and microwave and TV at the same time without it tripping the breaker. Bad design on my part. Seems like this RV was created for moderate temperatures. Good luck.

[f350chief]

Joseph.Feucht Does the two a/c units cool the fifth wheel camper down better than one. I am thinking of adding the second a/c to my fifth wheel and everyone tells me it will still be only 20 degrees cooler than the outside temperature no matter how many a/c units you install

[Bob Landry]

Joseph.Feucht Does the two a/c units cool the fifth wheel camper down better than one. I am thinking of adding the second a/c to my fifth wheel and everyone tells me it will still be only 20 degrees cooler than the outside temperature no matter how many a/c units you install

The people telling you that are giving you eroneous information. As I stated above, the outside temp is unrelated to the 20 degree split that is often refenced in all of the RV forums and does not seterming the temperature inside the trailer. How effective your air conditionrr(s) is/are is determined by the several factors including but not limited to BTU capacity, insulation, ducting, and shade or overhead covering. If you by chance see a difference of 20 degrees between the ambient temperature and the temp iside the trailer, it's merely a coincidence and not a function or property of the AC.

The 20 degree difference is the difference between the discharge air coming out of the unit and that of the return air being drawn back in to be recirculated through the evaporator coil. 18-20 degrees is optimal, a larger split most often is indicative of an air restriction in the ducting or a clogged return air filter. This is noticable by holding your hand directly in front of the discharge. If it feels very cold, but cannot be felt from a short distance away, then the flow is restricted. The general idea is that to cool air, you must move it. No flow, no cool regardlsess of the size of the unit

Also be aware that to run two ACs simultaneously, 50 service will be required.
My guess is that most fivers are probably under cooled with one AC regardless of the BTU capacity

[f350chief]

Bob, Thanks for the reply. I was thinking of adding the second ac unit on the fifth wheel but was going to run it off of the 15/20 amp seperate cicuit on the campground power supply. I was going to install this usinga seperate plug to the camper that went straight to the second ac only. Have you ever heards of someone doing this and do you think it will help?

[Bob Landry]

Bob, Thanks for the reply. I was thinking of adding the second ac unit on the fifth wheel but was going to run it off of the 15/20 amp seperate cicuit on the campground power supply. I was going to install this usinga seperate plug to the camper that went straight to the second ac only. Have you ever heards of someone doing this and do you think it will help?

Yes, I have, it's a commom practice and pretty easy to do. I'm going to do it to my new trailer, not to run a second AC, but to have a power sourcre that is separate from the 30A service to run ceramic heaters during the winter, air compressor, etc. and not load down the 30A system. If you are going to go that way, I would recommend that you spend a few bucks and get an additional marine type breaker panel with a double pole breaker that serves the same type function as the one on your converter that the shore power connects to. The purpose there is to give you a little more protection than the pedestal breaker affords because if you have a problem and the breaker trips, both the hot and neutral legs are broken. A panel with a DP 20A breaker and two or three output breakers would allow you to run a protected circuit for the second AC and also to outlets that could be used for other purposes and would be protected by circuit breakers. The marine supply stores will have what you need. I'm a firm supporter of Blue Sea products as I think they make a really quality product. I do a lot of marine wiring, and I don't think you can have too much protection.

Whatever you do, have a qualified electrician inspect your installation if you are going to do it yourself. I realize that RV builders use the NEC for electrical installations. My background is in the marine industry so when I do something I do it by marine standards. We follow ABYC suggestions and US Coast Guard regulations, which I think are more stringent, so to me, if it's suitable for a boat, it's good for a RV. Others may disagree and I'm not going to argue the point with the code police. It's just my way of doing things for the past 15 years and it works for me. As long as you have a safe installation, that's what counts.

[Terrydactile]

To the OP.. I ran across something on my A/C unit while doing routine maint that you could check. I am assuming you have ducted air, if so, remove the inside cover from your A/C unit and check to see how well the duct work is sealed. Mine was not sealed therefore cool air was being blown into the attic space. I removed the individual vent covers and found the same problem. I also found the the duct tape was coming off the ends of the duct run too. I sealed everything up with a good quality aluminum duct tape and wow what a difference. I have heard of many people that found the same issue with their duct work.

Although this may not completely solve your problem there is no good coming from blowing cool air into the attic.

[f350chief]

Thanks for the additional info. I will check the duct work on the camper but I also like the idea of adding an additional outlet to run ceramic heaters in the winter. Thannks to all for the great feedback.

[hankaye]

Howdy All;

One thing that I have discovered is the bit about Air Conditioners is that they were designed to remove moisture (humidity), from the air.
I grew-up in the Humid East. I now live in arid Utah (little to none on the humidity scale).
Here in Utah (and a large part of the Southwest), the folks use evaporative cooling (swamp coolers to put moisture INTO the air creating cooling. There is ONLY ONE State dryer than Utah and that be Nevada.
AC's function best in humid enviroments. Swamp coolers work best in dry... Something to remember when one starts to bang on the poor machine...

hankaye

[Paddler]

Something else you can look into is managing the amount of radiated heat that is entering your trailer. Here in sunny Floridah, we put the reflective foil material in sun facing windows to reduce the heat buildup along with the vent insulators Camping World sells to block heat from the vent covers. I also insulated and block light and heat from entering the dome over the shower enclosure. All this stuff also works in the winter to help keep the trailer warm.