25FB / 27FB Ducted AC question w/ 2 AC

[kdkool]

Looking at getting a new 25FB / 27FB but I'm a little unclear about the AC options.

I'm assuming that when you get a single AC unit, the ducted system blows throughout the whole unit, front and back. What about the dual AC system? Does the frontward AC only blow to the front zones and the rearward AC blow to the rear zones? Or does both ACs blow throughout the whole unit?

The reason I ask is because I'd like to run the AC with either a generator or my lithium battery bank (15.6kWh - 5000W inverter) but would ideally only run a single AC when doing so.

I'd lean towards a single AC system if the dual AC systems are zone split. I'd also like 2 ACs for redundancy and extra cooling. :-(

[tbrowne]

Dual air blows throughout the trailer regardless of which unit is operating. Cooling is faster with both units running but AC isn't isolated depending on the AC unit that's in use.

[Warpath]

If you're looking at getting a 27 and plan on camping anywhere that gets hot, a dual ac is mandatory. One ac will not be able to keep up in ur tin foil trailer.

[starlite29]

On a dual AC unit with a CCC2 thermostat, you have two heating/cooling "zones" and two thermostats. Both units blow through the same ducts but my experience is that there is significantly more airflow from the rear when the rear unit is on and vice-versa, for obvious reasons. In practicality, our 25ft unit is too small for "zones" to really be of much use but the ability to control both units independently is there.

If you're traveling exclusively in the north, some members would advocate for having a second fantastic fan in lieu of the second AC. You appear to be in GA however so (as mentioned) the second AC would be pretty much a must-have for summer travels.

BTW is this 1000ah battery bank in the TV? Sounds pretty awesome.

[2012FB]

My 2012 25' only had one AC unit I would never own another 25' without dual AC units. In fact, I went out of my way (Dallas) to find my 2022 25' that had dual AC.

[Eddie B]

I installed a Micro air EZ start on my front (bedroom) AC bedroom of the two ACs as it keeps the sleeping area colder. I have a 25 globetrotter and yesterday during the hottest part of the day started up the small Honda generator to see how long it would take to go from 90 degrees inside to a “comfortable” temperature. It took almost 3 hours to cool down to 80 - but it felt great. I bought 2 acs and never ever regretted it. One ac broke at Palo Duro in July (why was I thinking?) and with one ac we almost didn’t make it. Temperatures were extreme - but great to have that second AC - especially with pets.

[kdkool]

Originally Posted by starlite29

BTW is this 1000ah battery bank in the TV? Sounds pretty awesome.

No it's a battery bank that I have in my current airstream that will move over. It's a 48V system consisting of (16) 3.2V prismatic LiFePO4 cells with each cell rated for 304aH.

[kdkool]

Originally Posted by starlite29

On a dual AC unit with a CCC2 thermostat, you have two heating/cooling "zones" and two thermostats. Both units blow through the same ducts but my experience is that there is significantly more airflow from the rear when the rear unit is on and vice-versa, for obvious reasons. In practicality, our 25ft unit is too small for "zones" to really be of much use but the ability to control both units independently is there.

If you're traveling exclusively in the north, some members would advocate for having a second fantastic fan in lieu of the second AC. You appear to be in GA however so (as mentioned) the second AC would be pretty much a must-have for summer travels.

BTW is this 1000ah battery bank in the TV? Sounds pretty awesome.

Awesome. I just wanted to make sure that if I run a single AC, it'd blow to both ends of the trailer. This makes it a no brainer to do 2 ACs for me regardless of 25 or 27. Thanks!

[daleyocum]

I’ve been happy with a single AC in a 25’ because we seldom camp with hookups. Our single Honda generator and Lithium battery bank + multiplus can power one AC but not two. I also love having the second fantastic fan. I can see the need for two ACs in hotter climates if you tend to stay in places with 50a hookups.

[Atwebs]

We have a 27 with 2 air conditioners, since we got it in 2018 we have never run both at the same time, you can select whichever one you want to run, we select where we want cool air. We do open the windows, turn on the fans and sit outside in the shade when it is hot and we prefer that. The only advantage to having 2 is you COULD run both if you had the power and wanted tomdomit.

[solomon.m]

We have a 27' with two A/Cs and usually run both when we initially arrive and plug in at a resort to get the initial cooldown. After that we run the one further away from where we are using the rig. In daytime when we are in the lounge we run the front AC. The ducted venting delivers cool air to the front and rear of the trailer and the noise stays in the front. At bedtime we turn off the front AC and use the rear to again keep the noise out of bedroom but still deliver cool air throughout. One note, the thermostat is installed in the bedroom and a remote probe under the TV in the lounge. This lounge probe gets some influence from the refrigerator and sun shining into the lounge. I usually have a look at the "current" indicated temperature of each zone and set the target temp a few degrees up or down from that reading rather than getting hung up on a particular desired temperature.

[DewTheDew]

We have a 27' with ducted dual ACs. As noted here, both work about the same (one is slightly larger but I always forget which when I am staring at the controls!) and one blows front and back. When it isn't baking hot and we only need one, we use the one over the bedroom during the day and the one over the dinette at night just to keep noise down. Similar to solomon (just read that post).

Your battery set up sounds awesome!

[Jeff Bittner]

2021 25FBT International with 2AC's and 2 Softstarts. With 2 ACs they each don't have to work as hard and I can run both on 30A, one AC with my Honda 2200, or one on housepower with a quality ext cord. Just set temps to what feels good as thermometers do read different font and back as above.

[Wross]

Our 25 ft RB has one AC, it has no ducts. It has 2 fantastic fans and the AC is between the Stove and Refrigerator in the center "hallway". We live in Austin, TX and it works OK in the 100 degree days if you have it on all day, but cooling down when ariving to a new site in the afternoon requires a process:

1) exaust the hot air with Fantastic fans while you start up the A/C,
2) Close the fans
3) close the curtan/door to the bedroom, the bath so you are only cooling the front lounge of the trailer,
4) drive to the store, shore, bar, or whatever for 45 minutes or longer, enjoy the A/C in your tow vehicle
5) drink a cold beverage as you hang in the front longe of the trailer, and then after 1-2 hours,
6) open the doors/curtains to start cooling the rear bedroom.

The A/C has vent controls to direct the air towards the front or the back. It has no ductwork. For sleeping we direct all the air to the bedroom area

I added a micro-air easy start, and can run off the Honda 2200 with no issues, but we typically have hookups at the state parks and most places we stay. We go to music festivals and many have no electrical hookups.

In summer we head north, or to higher elevations. I drive from Austin, and the next day I am typically at four corners, entering Colorado from New Mexico, no A/C required

[brick1]

As others have noted, both AC units blow through the front and back air outlets. In addition to having redundant AC’s, you also get the benefits of 100 amp (2 X 50) total electrical capacity. You won’t be popping breakers when you try to run both AC’s a hairdryer, microwave and pretty much everything in the AS.

[Eddie B]

Jeff - I have been tempted to try and start my ez-start/micro-air equipped AC with 110 shore power, but haven't been that brave. I am guessing you do it regularly with no wear and tear on the airstream A/C? I have the propane 2000 honda - but sometimes at a harvest host I will have 110 available - it would be nice not to have to run the generator. Thanks, Eddie B.

[Fortemd]

27FBT with 2 AC units. Like the ducted air. Note that there’s are 6 vents in the galley, one in the vanity/toilet, but only two in the bedroom.
Both AC units dump into the common plenum, so the bedroom is always “wife-hostile “. The solution is to close a couple of the galley vents in order to force more cold air into the bedroom.
Just left 98 degree weather in Hurricane, UT. My wife froze me out of the unit.
With an EZstart on each AC unit, I can run both units (and refrigerator) on my 30 amp 7.2kw F150 generator.

[2012FB]

Our 2022 FC 25' RBT has 4 vents in the bedroom and it can get pretty cold which is to my liking with my wife complaining about needing a second blanket.

We just returned from the Vineyards campground on Grapevine Lake outside Dallas. Wow! what a very nice park indeed. It was in the high 90s with 60%+ humidity. We headed out midday and I left only one AC unit on, the center coach unit, to keep our German Shepherd cool while we were gone. We came back later in the afternoon and the temp was 79 and it was running continuously. After that, I kept both on.

[Jeff Bittner]

Re: 1 AC on 110. The quality of the site power matters. My surge protector has popped a few times but usually I'm just looking for a quick test of things or a quick cooldown before hitting the road. Most Harvest don't mind the quiet Hondas. We camped at Rick Cut last weekend with temps in the upper 40s and it was nice running 2 heat pumps on 30A with Soft Starts instead of using propane. Nice setup.