AC in the heat

We have a 33ft. 5th wheel TH with two 13.5k a/c's (one in the front bedroom; one in the much larger main living area). On a recent 115 degree day (5 percent humidity) the smaller bedroom area would chill out around 72-74 degrees and the main living area would never get below 82-83 degrees. We used a high velocity squirrel cage fan to blow the much colder air from the bedroom area into the main living area (via the hallway). Temps in the main living area improved quite a bit, down to 79-80 degrees. Although we would have preferred a couple degrees cooler, considering the blistering heat outside, 79-80 still felt awfully nice.

Needless to say, the compressors on both a/c units never cycled for most of the day. We estimated we were using about $10 worth of electricity each day (compressors did cycle somewhat at night). The full hook-ups only cost us $17.50 a day.

Our Grand Design 303 RLS in direct heat without humidity will keep about 20* to 25* difference from outside temp with shade and tinted windows insulated with foil bubble stuff. In direct sunlight max difference at about 20*. I am not an a/c expert but my a/c guy at home said you can loose about 30% to 40% cooling efficiency with high humidity cause a/c has to de-humidify also. Worse scenario, go to the pool, shopping or a movie during the hot part of the day! ! ! Good Luck & Be Safe ! ! !

Thanks so much for all the replies. It will be 94 here in DFW today so we have the rig set up and cooling out front. At the duct outlet with the longest run from the units, the air is coming out of there at 59, with 56 at the unit. I suspect the ducts will warm up as the day goes on with no overhead shade, but we are hoping this was more a condition of our surroundings and less about the unit.

Here's to Hope!

I think you have AC problems. Based on your original post, if the outside temp is 97, you can only bring the inside temp down to 85 and that is with running both your AC units. I just don't think that is adequate. If you said those numbers were based on only the 15k unit, then I would believe it, but now with both running. I would have them checked by someone who knows what they are doing before spending big money on replacements.

I have two ACs and I can turn my rig into a meat locker if I want to. I know that shade helps and insulation helps, but I still you have AC problems.

I feel the heat and humid weather way before my wife,So being our 5er has a 15k in the rear and a 13k in the bedrm..We start running the ac as soon as the the outside temp gets to 78. Doing all of the above helps but we bought 2 large fans- one in the livingrm (pedestal type) and the other for the bedrm, and wow do the 2 fans make a big change in how much ac you need to keep cold

tomthyme wrote:
A couple of answers...

. we have all windows covered with reflective bubble stuff
. our roof vents have fantastic fans and vents on them, but we have not put the pillow insulation in yet
. there was no shade

in Destin FL

where we were
. one day we left for a day on the water at 830 and got back around 2. It was 87 outside and 78 inside - no doors had been opened, etc. until we got home
. we have tried the 'quick cool' feature but that doesn't seem to help
. we run a ceiling fan, 1 tower fan and 2 smaller fans all day
. we keep it dark (no lights)
. we don't cook inside when it is hot
. we were on a concrete pad (reflects heat)
. if there is a way for me to add a 3rd air to my already built rig, I would love to hear it

So, all in all, we were disappointed. We are thinking of swapping our airs for 2-15kbtu units from Dometic. We have read good reviews about the new Coleman 15k units too.

Thanks for the ideas and input folks. Hopefully we can figure this one out. We don't full time, but have a

trip to Door County at the end of August

so we will definitely need good AC for the trip.

Thanks again!

Don't be disappointed! You were in Destin, FLORIDA! That's what the problem is not your RV!

I won't sit in an RV with the windows totally blocked for the sake of being cool, but I sure had to come up with answers when I was parked in Florida.

Pick up some 'removable' limo tint from Walmart and put it on the windows. Take your time applying it and it looks like a professional job. I was only going to use it for the time in Florida but I've left it on. Keeps the coach area cool when traveling.

Get those pillow vent inserts.

And they make a insulation cover for RV door windows. Lot of heat comes thru that window. I didn't mind covering just that window.

You won't experience ANY of that horrific type of Florida heat in Door County, WI.

Your RV air conditioning will freeze you out in Door County!! I used to live near there. :W

A couple of answers...

. we have all windows covered with reflective bubble stuff
. our roof vents have fantastic fans and vents on them, but we have not put the pillow insulation in yet
. there was no shade in Destin FL where we were
. one day we left for a day on the water at 830 and got back around 2. It was 87 outside and 78 inside - no doors had been opened, etc. until we got home
. we have tried the 'quick cool' feature but that doesn't seem to help
. we run a ceiling fan, 1 tower fan and 2 smaller fans all day
. we keep it dark (no lights)
. we don't cook inside when it is hot
. we were on a concrete pad (reflects heat)
. if there is a way for me to add a 3rd air to my already built rig, I would love to hear it

So, all in all, we were disappointed. We are thinking of swapping our airs for 2-15kbtu units from Dometic. We have read good reviews about the new Coleman 15k units too.

Thanks for the ideas and input folks. Hopefully we can figure this one out. We don't full time, but have a trip to Door County at the end of August so we will definitely need good AC for the trip.

Thanks again!

tomthyme wrote:
So, what do you expect from your rig AC?

We have a 13k BTU AC in the front/master and a 15k BTU in the living. At present, the main 15k AC is keeping the rig at 10-12 degrees lower than the outside temp, with the bedroom AC running (all ducted). So, is this reasonable to you? We would like 20 degrees cooler and are ready to buy something new. The current 15k unit is 3 ears old, our 2nd on this rig. Maybe that's the price of living n Texas?

We've a single 15k unit on our Monty. Last year we went out to CA and encountered 114 degree (but dry) heat. We consistently got an 18 to 20 degree drop during the day, but this was with all windows and vents blocked with reflective insulation, awning out, but no shade. Since we were visiting relatives, we spent days in a nice air conditioned home and only went back when the sun was down. The AC would actually cut off before daylight after getting the inside temps down to 74. What you are experiencing could be due to humidity, no window insulation, lights & other inside heat sources, and opening & closing the door. I'd also check your ducting to be certain it's working and not blocked.

I think it also has to be said that WHERE you are RV'ing makes a BIG difference how well your AC can keep your RV cool.

For years I only RV'ed in the Midwest and had no problem keeping the coach cool in the summer no matter how hot it got.

THEN I went to Florida. The intensity of the sun in the South is just incredible. Quite frankly I was shocked that my ac could not keep it cool inside the RV without a LOT of help from me. It was a big learning curve for me the first time I decided to stay in Florida in the summer.

It's just part of learning the ins and outs of RV'ing in the Southern heat.

Why do you think the Snowbirds beat feet back up North before summer hits? :B:W

Well can't be too disappointed with out OEM Dometic 15K BTU on our 2005 Copper Canyon, we sit in full sun and at 98 outside we were at 80. We are looking at a second 13.5K unit for the bedroom.