POLL: AC BTUs, Trailer Size, and Climate

[Shiloh]

So my 43 year old ac has died. I have to get a new one and quick. I was up half the night looking for information on BTUs and trailer size, and I found A LOT of conflicting opinions, a little on home BTU requirements, but nothing conclusive for use in an airstream. (insulation issues, cough, cough)

So here is the poll:

What is the size of your trailer? (expressed in linear feet, mine is 30)

What brand/model AC do you use?

How many BTUs is your AC?

What are the warmest temperatures you typically see?

Do you feel that your AC is adequate for the size of your trailer and the climate in which you use it?

If enough people answer this maybe we can get some useful data. I don't really trust the AC companies, and from everything I've read it seems an airstream is a unique application... Thanks in advance!

[richinny]

get a 15k btu unit.

[jkcru]

I agree with richinny

[TinLoaf]

I have a 25 foot trailer with the 13,500 BTU DuoTherm Penguin. It is more than sufficient 95% of the time, but of course it can't keep up when it's 90+ degrees and parked in the sun. It still cools, but it will run continuously and not get down to the set point.

[vswingfield]

I have a Carrier 15,000. It's not big enough.

Yes, I'm painfully aware that there are no larger units made.

It doesn't get miserable in 100+ full sun provided you wear shorts and sit in front of a fan, but you wouldn't call it comfortable either. Closing off the rear of the trailer helps some, but a second unit would be better—just not in the budget right now.

Since Carrier has exited the RV business, I would not buy a Carrier now.

[tpi]

I have 25' trailer w/ 11K btu used in southwest. If I had to replace the air conditioner I'd put a 15K on it.

[Secguru]

I have a 34' equipped with two A/C's. Up front 15K, in back 13K. South Texas gets pretty hot in August, but this combo keeps up with it.

[Jammer]

What is the size of your trailer? (expressed in linear feet, mine is 30)

30 feet

What brand/model AC do you use?

I have two Dometic Penguins, one in the rear bedroom, one in the main area

How many BTUs is your AC?

I believe they are both 13,500 but I'm not sure because I haven't had them apart to check and the factory sales order isn't clear.

What are the warmest temperatures you typically see?

Typically 95 degrees, sunny, and humid.

Do you feel that your AC is adequate for the size of your trailer and the climate in which you use it?

The bedroom unit is sufficient but the unit for the front of the trailer is not.

[Olie]

I have a Duo-Therm 13,500 which is totally inadiquate when temps are above 90 F. We travel a lot along the Gulf coast and west on I 10, up to northern New Mexico. A lot of time is spent around Las Cruces area as we have family there. If we camp in the shade the AC does a "just bearable" job.

If I were replacing mine I would go with a 15,500.

What about electrical wiring gage if you go to 15,500? Will the existing wire for 13,500 support a 15,500?

[vswingfield]

Originally Posted by Olie

I have a Duo-Therm 13,500 which is totally inadiquate when temps are above 90 F. We travel a lot along the Gulf coast and west on I 10, up to northern New Mexico. A lot of time is spent around Las Cruces area as we have family there. If we camp in the shade the AC does a "just bearable" job.

If I were replacing mine I would go with a 15,500.

What about electrical wiring gage if you go to 15,500? Will the existing wire for 13,500 support a 15,500?

Yes.

[Gene]

Shiloh,

We have a 25' with 13,500 BTU DuoTherm. It works fine until the temp hits 90˚ and then it struggles. By 100˚, the temp inside is around 80˚. If we are traveling in high temps, it can take long, long time to cool the inside. It helps to have the awning out if the sun is on that side, close the blinds and curtains and put Reflectix on the windows.

If you have to seal yourself in, the A/C and insulation is certainly inadequate.

I suggest the biggest unit you can get, or two units. And try to go to the mountains or up north.

Gene

[MervM]

We have a 28' 2009 Flying Cloud . We live in SE Saskatchewan , our temps can reach 80 degrees plus F. Our A/C is a 15,000 BTU , we find it adequate for our needs. Using the Fantastic fan in the bedroom and the A/C in the front area together are a good combination.

[lewster]

Remember that any RV roof air conditioner is only rated for a 20*F temp. drop from the ambient air in the trailer. This means that the air coming from the unit thru the evaporator (cold air) will only get 20*F colder than the air going into the unit thru the air return/filters.

Knowing that the aluminum skin of an Airstream has almost as much heat absorption as a black skinned trailer (the white roof does help a bit), I would use 2 units if you have the capacity to do so, or at least a single 15K unit. I see many motor homes that have 3 roof units now (mostly all 13.5K units).

If I had a 30' Airstream and was going to be using it in very warm areas, I would use a 15K for the main living area and a 13.5K for the bedroom. Using 2 units at the same time will require 50 amp service though, and you may have to re-wire your trailer for this capacity.

If you have a 13.5K unit now, it is an easy replacement for a 15K upgrade. The 20 amp circuit breaker and wiring will be the same either way.

[stowaways]

I'll take a shot. We full-time in the DFW area in a 2007, 27' Safari with one 15K unit. We're restoring a 30' '69 Sovereign and plan to install two 15K units -- but here's the option we chose. Rather than re-wiring for 50 AMP, we are choosing to have a 110 plug for the second unit which connects directly to the shore power. Currently, in the '07, when the temps reach 90-100, we're lucky if we can maintain 76 degrees inside -- and that's in the shade with fans circulating the air. I say nothing under a 15k if you're in Texas! Good luck.

[JFScheck]

30 Foot 2011 Classic, two A/C units, 13,500 in bedroom & 15,000 in front above galley.

[Shiloh]

Well, I am glad I decided to do a little research and not take the (very nice, well-meaning) repair man's word for it. He wanted to put in a 13500 but I didn't think that would work. It will probably be at least 90 the majority of the summer... Thanks everybody for contributing!

[pattonsr]

Lew,

If Airstream would entertain (big if) an upgrade to a 15k unit on a new Interstate, would the on-board Onan generator start a 15k? Is there much difference in starting a 13.5 versus a 15k? I was told by a dealer that the 13.5 unit is ac only (not a heat pump). I am not sure if that makes any difference. It gets hot in Texas.

Barry

[Gene]

The 13,500 BTU unit in ours has a heat pump. It's possible that in the newer ones they didn't include that option.

Gene

[pattonsr]

Gene,

I am talking about a 2011 Airstream Interstate class B which comes with a 13.5 a/c unit without a heat pump. Sorry I didn't make that very clear. The Interstate is so expensive but most everything is included and of a higher quality than the usual Airstream choices.

Is there a downside to having a 13,500 BTU heat pump? Possibly a larger startup draw which the on-board Onan generator couldn't handle or is this the usual Airstream decision which defies logic?

The same questions come up regarding the 15,000 BTU heat pump. Lew said the wiring is ok to go to a 15K from a 13.5K. So why doesn't Airstream always offer an upgrade to a 15,000 BTU unit? I doubt that the Interstate is any better insulated than the Airstream trailer line.

I may be wrong but I would like to hear from anyone that has an Interstate that is comfy with a 13.5K unit sitting in full sun on a typical 102 degree day in Texas.

Barry

[tpi]

You can check page 3 for some specs on Dometic Penguin.

http://www.dometic.com/b3056cd0-1a5b...2d4ac84d.fodoc

I don't know how much spare capacity the built in generator on the Interstate has. The capacity varies due to temp and elevation.

The 13.6 vs. 15K btu are within about 10% of each other. They are not night and day different.