2nd AC size

[kfp673]

We have a 37' travel trailer. For travel trailers and 5th wheels in the 35-40' range, I am curious if most of the second AC units (Bedroom units) are 13.5k or if people opt for the larger 15k. We are pre-wired and looking to add the second soon. Considering we have been living with the single for 4 seasons I suspect the 13.5k will be plenty and possibly a tad quieter, but I'd like to hear from those who have added it and which way you went. Thanks!

[philh]

wanderingaimlessly wrote:
No, I'm not suggesting running two AC units off of a 2000 watt genny, but you can run a single little 9000 btuh AC on the small genny, which is not normally doable with the 15000 unit.

Install microaire ez start and you can run the AC off of a small gen

[Rick_Jay]

Well, when we were ordering our rig back in 2004, I opted to put the same 15k BTU unit in the back as was up front. Our system IS ducted, so that's definitely a benefit. BUT...even if you didn't have ducting, you could put a small floor fan in the bedroom and blow the cooler air up front if need be. Not as convenient, but it'll work.

Another thing to think about is the larger unit can cool a given space in less time, so if you've been on the road all day and the bedroom area is hot, the larger unit should cool it down quicker.

I believe you're from PA. If you stay in the northern part of the U.S., probably any additional cooling would be appreciated. But I can tell you that when we spent July & part of August down in Florida a few years back, there were some days we used every bit of the capacity of both A/Cs. The highs for the better part of a month were 93-98, with high humidity, and the lows at night were mid-80's. We had 5 people and 2 dogs in the rig, so lots of heat generated by breathing bodies! LOL

Lastly, when we were ordering, I figured that by having the same units front & back, that IF the front A/C decided to act up while we were out camping, we could probably swap the working rear A/C for the failed front A/C without having to do a full replacement. That could at least keep us going until we got home. We always travelled with the kids, so we really need a functioning A/C up front. Of course, once you plan for that problem, it never happens. LOL I probably shouldn't say this, but our two units have been pretty much trouble free since new, other than a relay got stuck around the 7 year mark or so.

I've always been of the mindset that it's better to have it and not need it, then to need it and not have it. However, I understand what those are saying IF you do a lot of boondocking and it would be handy to run a unit off a small generator. Which I guess leads us to the question: Do you have a generator? The size of which might help make your decision for you.

Good Luck in your decision.

~Rick

[wanderingaimles]

valhalla360 wrote:

wanderingaimlessly wrote:

valhalla360 wrote:

wanderingaimlessly wrote:
The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

You aren't running 2 air/con units off a 2000 generator.

If you plan to run the air/con off grid, better to jump up to a 3000w generator.

No, I'm not suggesting running two AC units off of a 2000 watt genny, but you can run a single little 9000 btuh AC on the small genny, which is not normally doable with the 15000 unit.

Still better to jump up to a suitable generator (up around 3000w) but a 2000w can usually work if you use a soft start and make sure nothing else is running...but that applies even if you put in a small air/con. It's the startup load that is the challenge for undersized generators.

I asked a question about HOW they camp, and offered that IF they frequently dry camp, they MAY want to look at a smaller AC that a 2000 watt genny COULD RUN.
I'm not trying to spend unlimited amounts of someone elses money.
That is the purvue of others.

[jdc1]

I take it you have a 50A connection? Running 2 AC's on 30A...Hmmmm.... Start there. You may need to consider a slow start capacitor installed on both units if you have 30A connection.

[valhalla360]

wanderingaimlessly wrote:

valhalla360 wrote:

wanderingaimlessly wrote:
The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

You aren't running 2 air/con units off a 2000 generator.

If you plan to run the air/con off grid, better to jump up to a 3000w generator.

No, I'm not suggesting running two AC units off of a 2000 watt genny, but you can run a single little 9000 btuh AC on the small genny, which is not normally doable with the 15000 unit.

Still better to jump up to a suitable generator (up around 3000w) but a 2000w can usually work if you use a soft start and make sure nothing else is running...but that applies even if you put in a small air/con. It's the startup load that is the challenge for undersized generators.

[wanderingaimles]

valhalla360 wrote:

wanderingaimlessly wrote:
The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

You aren't running 2 air/con units off a 2000 generator.

If you plan to run the air/con off grid, better to jump up to a 3000w generator.

No, I'm not suggesting running two AC units off of a 2000 watt genny, but you can run a single little 9000 btuh AC on the small genny, which is not normally doable with the 15000 unit.

[Lantley]

valhalla360 wrote:

wanderingaimlessly wrote:
The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

You aren't running 2 air/con units off a 2000 generator.

If you plan to run the air/con off grid, better to jump up to a 3000w generator.

When off grid 1 A/C may due. Having a lower wattage unit will have an advantage when power is coming from a smaller genset.

[valhalla360]

Super_Dave wrote:
If it is just for the bedroom, a polar cub 9 or 11 would be more than enough and possibly quiet enough to sleep with while running.

Is there something wrong with your air/con? We've always slept with it on. Much easier than sleeping in a pool of sweat.

As far as short cycling...if that happens, just open the bedroom door, so the excess bleeds out extending the cycles.

[valhalla360]

wanderingaimlessly wrote:
The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

You aren't running 2 air/con units off a 2000 generator.

If you plan to run the air/con off grid, better to jump up to a 3000w generator.

[Super_Dave]

P.S. - a big unit for a small space equals a lot of short cycles which isn't good.

[Super_Dave]

kfp673 wrote:
Thanks all! The unit is pre-wired for electric but not ducting. Should have mentioned that originally. So it would be a direct vent for the second. We have a front bathroom which currently has a vent and the bedroom has a vent. The factory vents can only be aimed not closed. So I intend to replace those with vents that can be closed helping cool the main living space and the bunk room more and then open all when we are on 30amp and can only run a single. Most of our camping is <90 F but being east coast it is often very humid. Anyway, sounds like most would for 15k for the bedroom. Maybe I add a box fan during the day to blow bedroom air out into the living space to help.

Thanks again all!

If it is just for the bedroom, a polar cub 9 or 11 would be more than enough and possibly quiet enough to sleep with while running.

[kfp673]

Thanks all! The unit is pre-wired for electric but not ducting. Should have mentioned that originally. So it would be a direct vent for the second. We have a front bathroom which currently has a vent and the bedroom has a vent. The factory vents can only be aimed not closed. So I intend to replace those with vents that can be closed helping cool the main living space and the bunk room more and then open all when we are on 30amp and can only run a single. Most of our camping is <90 F but being east coast it is often very humid. Anyway, sounds like most would for 15k for the bedroom. Maybe I add a box fan during the day to blow bedroom air out into the living space to help.

Thanks again all!

[wa8yxm]

I would recommend the larger 15K... The reason for this is that no matter how hot it is now it's getting hotter and hotter and hotter every year over the last several years has set records for "hottest on record" and you will be needing the added cool.

[wanderingaimles]

The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.