Single 15,000 BTU AC insufficient; 18,000 BTU? high vs. low profile

[fotoman1527]

We are not satisfied with the cooling capacity and noise of the single 15,000 BTU unducted Dometic AC that came standard on our 2012 Flying Cloud 27 FB. From experience this unit is too loud and has to work unsuccessfully, full-time, just to try to catch up when temps are at 90. We live in Florida and anticipate a lot of travel in hot areas this year. The unit has been checked and is operating properly, with about a 17 degree difference in temp between in flow and outflow. The tech said he could clean the coils and get us another 2 degrees, but that won't get us to the level of comfort and hopefully less noise that we want.

The Dometic rep at the RV show in Tampa last week recommended replacing the unit with a Dometic Air Command 18K BTU unit with heat pump, model 15026, and it's plenum, with remote 15021 ($866.48 plus $106.88 + $78 shipping plus $200 labor = $1,251.36 (it was originally an Atwood AC).

There was a string on this unit, but unfortunately it was last updated in 2014, and even then no one responded that they had upgraded to this option.

Have you?

Concerns are whether this unit will truly provide 20% better cooling, and whether it will be less noisy.

Issues have been taken on this forum with the aesthetics of a regular vs. low-profile AC unit on an AS, but I agree with the writer who said the issue is more pronounced with a trailer of less than 23 feet, vs. one that can be bulit with two AC units on top.

Please share your experiences and advice on helping us solve this issue of insufficient, noisy AC.

THANK YOU!

___
Here are the links I consulted:

http://www.airforums.com/forums/f44/...ht-121085.html

http://www.airforums.com/forums/f427...mp-120482.html

[ggreen63304]

Hi,
Some of the things I have read on the forums concerning heat and air conditioning have to do whether your airstream has the awning package installed. Folks have said that package helps quite a bit with the sun/heat.

[wulfraat]

A larger unit would move more air and thus would have a larger or faster fan... seems like it would be louder no? Why not add a second AC unit?

I will say that likely the only way you’ll really ever have piece and quiet inside (relatively speaking) while the AC is running is to make the move to a 2014+ with ducted AC. Much quieter that way vs having a jet engine running over head....that was one of the game changers when I upgraded from a 2008 to a 2017 trailer......

[Glenritas]

We installed a Dometic 15k unit on our '69 Tradewind mid ship . It blows to the rear sides and down great but the return air duct blocks most air to the front and it was loud.

I replaced it with a Colman mach 8 15k unit that blows front to rear only and is quieter.
It cools great but on 105* days in full sun it only cools down to 85* .

If I were to do it again I would go with 2 Colman Mini Mach 8.5k units so I could run one at a time on a Honda 2000i.or both on 50a service

[Rgentum]

1. For greater cooling, get a second AC.
2. For quieter cooling, get a trailer with ducted air.

[DBinSD]

I have heard people complain about their A/C unit when in fact it was they were operating in areas with insufficient power supply.
Before you dump it, make sure the power supply is correct.
With that said, a ducted unit is quieter.

[fotoman1527]

Thank you all so much for responding. Shades do make a difference, but while ducted air and dual A/C's are the gold standard in terms of AC muscle and low noise, we want to try one last upgrade before we give up a trailer with which we are otherwise so happy. We feel like we can put up with the jet engine noise if we can just get sufficient cooling given the warm places we will be traveling this year. Hence, my hope is that I can find someone who has installed the Dometic model referenced above and recommended by a most helpful and knowledgeable factory rep at the Tampa RV show. He said that although the unit is larger, it uses two motors and somehow manages to be more quiet, as well as having 20% more BTU's, than a low profile 15k unit.

[aswell]

Curious fotoman, did you go with the Air Command? If so, are you happy with your decision after using it this summer?

[brick1]

We have dual air in our 2018 Serenity.28 It can make ice cubes on even the hottest days. Last weekend we were at a site that only had 30 amp service. So only one AC. During the day we ran the front 15K AC, and at night the bedroom 13.5K AC. Outside temps were in the low 90’s here in Georgia, not as hot as it has been. During the day we could only get it down to 76F. Nights we dropped a few,, but never cool enough to keep us happy.
You can put the slightly larger air in, and it may be a bit better. But nothing beats ducted twin AC’s. Put the upgrade money towards a newer AS?
brick

[cwf]

our 34' came with ONE AC!!! 30 AMP!!

This was quickly resolved by AC Deux. and upgrade to 50 AMP... My wife can make bedroom as cool as she likes...

When we travel and temps mid to upper 80's then stop for the night, it will take a couple hours to get the inside comfortable for my wife... In TEXAS, you are lucky if you can maintain 80 degrees inside with all the awnings out..

So, I did a ceramic coating/sealant on the roof... I can drop temps now.. even in the upper 90's... unless I have a broadside to the sun and can't deploy the awnings. We also put the 'reflectix' in all the windows when traveling and leave in after we park.. at least until the AC starts cycling.

[aswell]

Bus Kote is on order, and based on research should help keep the temps down considerably.

The reason for the Air Command inquiry is related more to noise level than cooling capacity. Our 34' has a dying Penguin, and based on the noise coming from the Penguin II in my brother's 2015 Serenity, we will not be taking that upgrade path.

Will be ordering either an Air Command or Blizzard, just wanting to get feedback from people who have used them in an Airstream.

A Dometic support rep said any AC in an Airstream will be louder due to the metal construction, which makes sense, but they also said the Air Command is without question the quietest they sell. Pretty much convinced at this point...

[fotoman1527]

No, aswell, I did not I go wth the Air Command. A technician determined that even though our existing unit had been blowing cold air, it was not reaching factory specs in terms of the difference in temp between intake and outflow air. Several folks spoke to the negative aesthetics of moving away from a low profile unit. I couldn’t find anyone at the tine who had successfully made the switch to this unit, which was not reassuring. In the end we replaced the ac with the same one With factory spec air flow, and despite the fact that we have been in hot weather since April, we are actually happy we made that move, stayed on 30 amp and kept our great trailer.

[aswell]

Understand fotoman. Sounds like it all worked out for the best. Good a technician was able to resolve your situation.

I too am having difficulty finding people who have installed an Air Command on their Airstream and are happy with that decision. After reaching out to several people who have discussed Air Command AC's on this forum, two have responded with negative feedback.

In addition to not being anything close to low-profile, apparently there are issues integrating the furnace with the thermostat on non-ducted units, and the condensation hookups are not easily integrated with stock Airstream drain tubing, which Dometic warned me about.

Then there is the other issue of the fan running constantly, which apparently can be overcome using a separate generic thermostat and high-voltage relay, but that brings up the question of potentially damaging the electronics if the AC power is toggled too frequently.

So, it seems that a Dometic AC may be a better option, in terms of interfacing with the existing thermostat wiring, furnace, and condensation drain.

Thanks again for your feedback.

[pteck]

This is great and useful feedback.

I've been scheming plans in preparation for next summer. Need to change out my 13.5k unit on my 27FB, as that most certainly is undersized.

For those that have had the A/C professionally changed, how much do they typically charge?

I'm been planning to get a 15k Blizzard NXT. And rent a scissor lift and attempt to install on my own.

[fotoman1527]

Solid analysis aswel. Good luck!

[Silvertwinkie]

This is curious to me because back in late 2003, I had a back and forth with the factory about upgrading to a 15k unit in a 25' Safari (from the 13.5k)and they and the dealer (or just the dealer playing both sides) hemmed and hawed about it for a few weeks, saying things like it's only 25', etc, etc, etc.



My response was, you put it in the 25' Classic and they finally agreed. In fact I think my 25' Safari was/is the only factory installed 15k unit for 2004 that is actually on the list of options installed for my VIN #. It was s $250 upcharge. After that 15k started showing up in a lot more units. Coincidence?!



If your 15k unit can't cool a 26-27' trailer, something is very wrong. I can hang meat in my trailer it can get that chilly-- in full sun with the awning deployed. I would make sure you don't have any significant air leaks going on and/or that the main entry door is sealing correctly. Many times the door doesn't fully seal and laws of thermodynamics kick in where heat and cool transfer where they meet and the door is often times the biggest culprit.


Back in '03 there were a number of folks here trying to talk me down from the 15k unit saying it would cycle too much, the humidity would be out of control. Nothing of the sort happened, and it works as expected, and maybe even better than expected. If there is such a beast (18k A/C unit w/heat pump), I'd do it. In fact it it were an option back in 03, I'd have done it.


Today, 15k units are common place, and in even more recent times, Airstream is putting 2 A/C units in a lot more sized trailers. At a minimum, 2 A/C units puts the cooling at 27k, far more than a single 15k unit.