Does a 25RB Twin Need 2 ACs?

[ROBERTSUNRUS]

Originally Posted by Al and Missy

My experience was different, for a different generation of 25. We had a 2001 Safari 25 RB twin with only an 11,000 BTU AC. Sitting in the sun, in my driveway, with 95 degree temperatures it kept the trailer comfortable, but I don't remember the temperature. It wasn't cycling, if I remember correctly, but we were never uncomfortable. It had the mouse fur walls and vinyl ceiling overhead so no exposed aluminum.

Our 2002 Classic 30 is another story. I will probably end up putting a rear unit in it.

Al

Hi, our 2005 Safari has one 11,000 BTU air conditioner and cools our trailer just fine. Like above, our Safari has small windows, mouse fur walls and a padded headliner. Not all camp grounds have 50 amp service and I wouldn't want to fight that huge power cord. Going on 14 years and no air conditioner problems. [must be a new problem]

[Gleverett]

We have 2015 25'FC with single AC. It has been fine but I agree with other comments on its how and where you plan on using the AS. If I bought anything bigger than a 25' I would definitely go with 2 AC's but using our 25' has been fine and we have traveled to GA, FL, TX, NM, Oregon, Washington state, and all states going and coming from our home in North GA over the last 4 years.
If I was full timing and lived in FL, deep south, or out west, dual AC's it would be. Good luck with your purchase.

[drbrick]

What is an AC for??? We live in the Great White North (Canada) where we run the furance in July

[Rgentum]

How about some objective evidence?

In our experience with our FC 27 FB, our one AC will cool the trailer about 15 degrees under outside ambient temperature. If you want more cooling, you'll need two ACs.

In our case, we're in the NW and are heatophobes, so we don't spend time in southern CA, AZ, or Mexico in the summer, so one AC (and the 30 amp cable) works for us. If southern latitudes in the summer work for you, I'd suggest twin ACs.

[Inholdings]

Just got back from the beach at Topsail Hill Preserve in our 1994 34' Classic to test out our new Atwood 15K heatpump. Did just fine with the outside temp at 88. Ran it on low and my wife asked me to make it warmer. She was cold.
I've had all the other a/c's except Coleman and this is a wonderful quiet unit that does not use a lot of amps. Highly recommended by a real user with experience.

[RidingmyRV]

If you are going to get a single AC see if you can upgrade to a 16000 btu vice the factory installed 13,500 btu. I’m hearing people with that AC don’t have a problem. I have a single 13,500 and on hot days it’s warm in the trailer. But the trailer cools quickly at night. One more thing and please remember this. Make positively sure your shore power connection is firmly connected to the male connector at the trailer, then tighten up the ring on the female end of the shore power cord. This will keep from having those connectors from heating up and possibly melt the female end. And never drop the female connector because that ring will break. Like mine. I dropped it on concrete while winding it up to put away.

[GeoBrite]

We own a 2023 Flying Cloud 25RB Twin and Live in Texas. The problem is not that the Airstream doesn't have decent insulation, the problem is there is no thermal break between the inner and outter skins. Both are riveted to the same aluminum frame. The inner skin tends to be ice cold in the winter and very hot in the summer. It radiates heat or cold.


If you plan on parking in direct sun with temps above 90, you will definitely need both units running to cool down the interior. You will need 50 amp service for both AC's without soft starts. We can run both on a 30 amp gen with Microair soft starts for a little while. It taxes the gen pretty hard.


Now, on a lighter note, with our trailer under the carport, It can be 100 and the small 13k will keep the interior cool. If you plan on using your trailer in mostly cooler areas, you can get by with a single 15K. However, if you plan on camping in warmer areas, it won't be a pleasant experience.


You'd think, since Airstream prides themselves as the best (and most expensive) travel trailers they would address this issue. How about a thermal break between the skins and the frame? How about closed cell spray foam in the wall cavities?

[gypsydad]

Originally Posted by RidingmyRV

If you are going to get a single AC see if you can upgrade to a 16000 btu vice the factory installed 13,500 btu. I’m hearing people with that AC don’t have a problem. I have a single 13,500 and on hot days it’s warm in the trailer. But the trailer cools quickly at night. One more thing and please remember this. Make positively sure your shore power connection is firmly connected to the male connector at the trailer, then tighten up the ring on the female end of the shore power cord. This will keep from having those connectors from heating up and possibly melt the female end. And never drop the female connector because that ring will break. Like mine. I dropped it on concrete while winding it up to put away.

That "connector" you reference is "NOT" recommended for an RV anymore let alone using it in weather, outside...even though most older RV's have them. Note: Airstream uses the Smart Plug on the newer models now.

I attended a seminar on this topic in July at the AS International rally and was surprised to hear the negative/danger of the existing plugs most of us have on our older AS's. Speaker said the existing older connector was never designed for use out doors in weather...not sure why/how they became so popular with RV manufacturers if that is the case. If interested, watch this video. https://youtu.be/sI0euVc-R3Q I sat thru Mikes seminar at the Ralley in July. There are [/I][/U]other Youtubes on this topic if interested.

https://www.youtube.com/watch?v=VTafJQGw4Fg

I talked with the WY Airstream dealer recently about this, and he said the conversion to this Smart Plug was not difficult and all the parts needed with instructions were included making the task pretty straight forward. A bit costly, but I am ordering mine this week. Amazon has them also.

[gypsydad]

Originally Posted by GeoBrite

We own a 2023 Flying Cloud 25RB Twin and Live in Texas. The problem is not that the Airstream doesn't have decent insulation, the problem is there is no thermal break between the inner and outter skins. Both are riveted to the same aluminum frame. The inner skin tends to be ice cold in the winter and very hot in the summer. It radiates heat or cold.


If you plan on parking in direct sun with temps above 90, you will definitely need both units running to cool down the interior. You will need 50 amp service for both AC's without soft starts. We can run both on a 30 amp gen with Microair soft starts for a little while. It taxes the gen pretty hard.


Now, on a lighter note, with our trailer under the carport, It can be 100 and the small 13k will keep the interior cool. If you plan on using your trailer in mostly cooler areas, you can get by with a single 15K. However, if you plan on camping in warmer areas, it won't be a pleasant experience.


You'd think, since Airstream prides themselves as the best (and most expensive) travel trailers they would address this issue. How about a thermal break between the skins and the frame? How about closed cell spray foam in the wall cavities?

Two AC's for sure in Southern states during summer. AS is at best, a "3 season" trailer, even though several owners use them during winter and take them to the snow...many posts on this; (but if you've ever stayed in snow in your AS, you understand the challenges, including propane use!)

My first 3 25' AS's only had single AC units. Took "awhile" to get cool for sure with single units. My 28' has 2 AC's and it cools down much quicker, and then you can select which unit you want to use to maintain the temps and reduce noise.

Recently I installed 2 new "aircraft" type vents I purchased from Vinnie while at the International Rally in July. These vents allow you to direct the air while providing no restriction to the airflow...cools down the area, real fast with the air volume they allow, compared to the AS vent covers! What a difference in cooling these make! Highly recommend if your looking for even faster, more efficient cool down! I only installed the 2 units I purchased, up front area, since that's the 15000 AC unit...which puts out more volume. Very happy with results.

One other comment about staying comfortable when camping in your AS...when in southern states, the "other" big deal is having a dehumidifier! Night and day difference in comfort...day and night. Stay cool!

[rodsterinfl]

This is an ongoing topic IMO, similar to tow vehicle stuff. I share my learned experience for whoever is interested.

First, I do not work in the HVAC industry but I had a good friend who did at Haines Heating and Cooling in Bonita Springs, FL. He gave me excellent advice on AC that applies in any situation.

Calculated BTU need for 25' Safari
There is a formula for calculating the BTU requirements in any given space. It accounts for insulation factor, people, volume, ambient temperature, window area, appliances, etc. All of that applies just as well to an Airstream. It is very detailed. I calculated mine (took me a long time) for a 25' Safari. It came out to 10ish BTUs with two people. My Airstream came stock with one Dometic Penguin 11K unit.

My friend shared with me that one of the worst mistakes people make, builders or owners, is oversized AC in homes. It causes all kinds of issues. A telltale sign is fast cool down (temperature drop) and dampness that leads, on hot days, to sweating inside and a clammy feeling that then leads to mold, etc. He further explained that it is better for an AC unit to run more than less as it has to run a cycle long enough to draw the humidity out of the space. So, even a unit smaller is better than one too big. He told me this on my house unit when I was going to close in my porch and cool it and wanted to check if my ac was adequate.

On an Airstream, we have less insulation and, depending on the model, the uninsulated window area is a major factor. A Safari has less window area than most models so, the BTU requirement would be higher and, most models no longer come with 11K BTU units but 13K or 15K- this would most surely compensate for any added window area.

After speaking with my friend I went to Radio Shack and bought a Clock, Thermometer with a Relative Humidity reading for the house. It was invaluable. When I bought the Airstream I bought one for it as a wall clock. I still have the Radio Shack model. The trailer clock was replaced a year ago.

When camping I plug in the Airstream and turn on the AC in the south east. It was in the 90's with high humidity this summer and all other summers since I have camped. I have been in direct sun in a field-style campground and in shade- all in 90's and always high humidity. The little AC runs and cycles and inside I am cool and dry with average humidity in the lower 40's and the temp inside varying from 76-80 degrees usually. Understand too that 76-80 is cool with low humidity- southwesterners know this.

This summer my school (I teach) got a new portable for my classroom. I went over in July/August to set up. It was in the high 90s. The AC was on 60 as they tried to cool it for me. It was stuffy, clammy and I was sweating inside. I took my Radio Shack meter over and the humidity was 72% in the room! Cool and damp. I got my dehumidifier out of the garage and took it to the portable. Two hours later it was 46% humidity and freezing in the room. I set teh thermostat to 77 degrees and it is now very pleasant. The AC is too big for the space.

Suggestion:
All this to say, your intended model is the same size as mine perhaps with more windows. If it has a 13500 BTU it has probably been calculated to compensate for windows and for two people. Get a Time, Thermometer, Humidity (weather clock) and monitor your inside humidity even if you get a 2 ac unit. Keep it between 35-50% humidity- that may mean running one ac. Also the awning package will help keep sun off of windows and a small fan can aid in circulation of ac air if not ducted. One unit works fine for me.

[Silver Ship]

I would recommend the 50 Amp option with 2 ACs. Although I live in the mostly cool Pacific Northwest in Tacoma, not far from Puget Sound, (the upslope breeze is great!) it can get very hot on some days, and I used "Maxine" to escape the heat on a 100 degree day with both AC running. It was a great place to escape the heat as my Brick home tends to become an oven after extended hot spells. Also it cools down much faster in a hot climate when you have a 50A service. A bonus is all of that 50A power that you can use to keep all systems running as you desire. After you get your trailer cooled down, turn one off. Another bonus is that you can run the unit that is farthest away from where you are in your trailer, be it the sleeping area or the dinette, thereby less noise and commotion for the best "Stream" experience that we all desire. ....J

[GeoBrite]

You are absolutely right. The stock AS registers block 50% of the air flow. No kidding! Even with the register completely open, the plastic backer blocks half of the air flow. Either this is a ridiculous design error or maybe purposeful. I know that home central air handlers require a certain amount of back pressure or the blower motor will over rpm and burn up. We're not talking about home AC here, though. Basically, the RV AC is a sideways window unit built to 1980's specs. Unfortunately, there aren't any federal mandates for SEER rating on RV units. They are extremely inefficient and take way too much power to run. Anything we can do to increase cooling capacity or reduce current draw is certainly worth trying.

[Bill M.]

It is 4 years later now. Maybe the OP could tell us which one he got and how he likes it?

[waninae39]

IMHO, 1 AC is fine- that way you get two fans. that is what we have and we use 1 fan to pull air in and the other top blow air out

with 2 AC , you lose 1 fan

most of the time, the fans is much better and far more silent that running the AC

[mikeinca]

Originally Posted by gypsydad

That "connector" you reference is "NOT" recommended for an RV anymore let alone using it in weather, outside...even though most older RV's have them. Note: Airstream uses the Smart Plug on the newer models now.

I attended a seminar on this topic in July at the AS International rally and was surprised to hear the negative/danger of the existing plugs most of us have on our older AS's. Speaker said the existing older connector was never designed for use out doors in weather...not sure why/how they became so popular with RV manufacturers if that is the case. If interested, watch this video.

I talked with the WY Airstream dealer recently about this, and he said the conversion to this Smart Plug was not difficult and all the parts needed with instructions were included making the task pretty straight forward. A bit costly, but I am ordering mine this week. Amazon has them also.

Thanks for posting the video. This is an upgrade I should do as I've always had concerns about the viability of that old style connector in bad weather. When I expect rain, I've taken to wrapping the connection with plastic wrap which provides some measure of "waterproofing".

[ROBERTSUNRUS]

Hi, the biggest problem that I have seen with the original 30 Amp RV plug system is that people don't twist the connector and sometimes don't use the ring nut. If it was a weather thing, I would be more concerned with boats.

[Mollysdad]

It's not always about heat.
1. It's good to have a spare.
2. If you run the bedroom A/C while using the living area, there's less noise.
3. Two A/C's means 50 amp service. That's 12,000 w. at your fingertips instead of the 3600 w. from 30 amps service.
4. You no longer need to pick and choose. "Can I run the water heater and the microwave together? "YES!"
Why not?

[gypsydad]

Originally Posted by rodsterinfl

This is an ongoing topic IMO, similar to tow vehicle stuff. I share my learned experience for whoever is interested.

First, I do not work in the HVAC industry but I had a good friend who did at Haines Heating and Cooling in Bonita Springs, FL. He gave me excellent advice on AC that applies in any situation.

Calculated BTU need for 25' Safari
There is a formula for calculating the BTU requirements in any given space. It accounts for insulation factor, people, volume, ambient temperature, window area, appliances, etc. All of that applies just as well to an Airstream. It is very detailed. I calculated mine (took me a long time) for a 25' Safari. It came out to 10ish BTUs with two people. My Airstream came stock with one Dometic Penguin 11K unit.

My friend shared with me that one of the worst mistakes people make, builders or owners, is oversized AC in homes. It causes all kinds of issues. A telltale sign is fast cool down (temperature drop) and dampness that leads, on hot days, to sweating inside and a clammy feeling that then leads to mold, etc. He further explained that it is better for an AC unit to run more than less as it has to run a cycle long enough to draw the humidity out of the space. So, even a unit smaller is better than one too big. He told me this on my house unit when I was going to close in my porch and cool it and wanted to check if my ac was adequate.

On an Airstream, we have less insulation and, depending on the model, the uninsulated window area is a major factor. A Safari has less window area than most models so, the BTU requirement would be higher and, most models no longer come with 11K BTU units but 13K or 15K- this would most surely compensate for any added window area.

After speaking with my friend I went to Radio Shack and bought a Clock, Thermometer with a Relative Humidity reading for the house. It was invaluable. When I bought the Airstream I bought one for it as a wall clock. I still have the Radio Shack model. The trailer clock was replaced a year ago.

When camping I plug in the Airstream and turn on the AC in the south east. It was in the 90's with high humidity this summer and all other summers since I have camped. I have been in direct sun in a field-style campground and in shade- all in 90's and always high humidity. The little AC runs and cycles and inside I am cool and dry with average humidity in the lower 40's and the temp inside varying from 76-80 degrees usually. Understand too that 76-80 is cool with low humidity- southwesterners know this.

This summer my school (I teach) got a new portable for my classroom. I went over in July/August to set up. It was in the high 90s. The AC was on 60 as they tried to cool it for me. It was stuffy, clammy and I was sweating inside. I took my Radio Shack meter over and the humidity was 72% in the room! Cool and damp. I got my dehumidifier out of the garage and took it to the portable. Two hours later it was 46% humidity and freezing in the room. I set teh thermostat to 77 degrees and it is now very pleasant. The AC is too big for the space.

Suggestion:
All this to say, your intended model is the same size as mine perhaps with more windows. If it has a 13500 BTU it has probably been calculated to compensate for windows and for two people. Get a Time, Thermometer, Humidity (weather clock) and monitor your inside humidity even if you get a 2 ac unit. Keep it between 35-50% humidity- that may mean running one ac. Also the awning package will help keep sun off of windows and a small fan can aid in circulation of ac air if not ducted. One unit works fine for me.

I disagree. 13500 AC on a 25 is "marginal" in summer, and just plain not enough cooling in the south, IMHO. All 3 of my 25' AS,s the 06' Safari, the 08 FC, and the "new" 2014 model we had got in 2014 all did not have "ducting" and only a single 15000AC unit. If you stood below the single unit, you could direct the vents to cool you down, and it would eventually cool the trailer to a tolerable level after a while. Could also maintain temps, but took a long time in hot weather. These units were noisy when full on, and took/take a long time to cool in many hot locations...always had to keep them running when in TX or southern states, because the AS is not insulated very well.

The 28' we have now has 2 AC's, ducted. The ducting done by AS, circulates the AC or heat pump air a bit better than the non ducted units on older models, but still the, it is restricted airflow so it is more comfortable to use both AC's to get it cool faster and maintain comfortable temps. Cools faster in living area with the 15000AC then does the 13500AC If you have a choice, live in areas where it gets "hot" in summer do yourself a favor and get 2AC's....(and a also get a dehumidifier if it is humid in your area.) You can sit around and "calculate" all you want, but do it in a more comfortable environment...besides, 2 AC units have better resale! (oh, and suggest you see the earlier post showing the improved ducting vents I installed from Vinnie; amazing difference in volume of air for cooling!)

[gypsydad]

Originally Posted by Mollysdad

It's not always about heat.
1. It's good to have a spare.
2. If you run the bedroom A/C while using the living area, there's less noise.
3. Two A/C's means 50 amp service. That's 12,000 w. at your fingertips instead of the 3600 w. from 30 amps service.
4. You no longer need to pick and choose. "Can I run the water heater and the microwave together? "YES!"
Why not?

True this post!

[Keys Dave]

We live in South Florida and mostly camp in the south. We recently purchased a 2 year old FC25FBQ. I wish it had a second a/c. The Unit now can only hold about 80 degrees in full sun at 93 or so out side. I will probably add one in the near future. If I do I will most likely add a second 30 amp plug and panel dedicated to the front unit. That may be unusual but it's much simpler and if I have only one 30 amp available I can just supply the main panel. IF I have a 50 amp available I can split it at the pedestal.