Opinions on new air conditioner

[skag101]

I have a 98 Windsport. It has two air conditioners but being a 30 amp rv i can only run one at a time. Pretty sure the ones I have are 13,500 BTU. We traveled to FL this spring and the air just didn't cool enough. We usually make two trips a year there.
Would it make enough difference to change to a 15,000BTU ? Cost for the unit is around $700-$800 for a ducted unit. Just wondering if it would make that much difference. What are your thoughts?

[Fulltimer50]

I would use the money to upgrade the electric to 50 amp.

[revjeffrey]

Originally Posted by Fulltimer50

I would use the money to upgrade the electric to 50 amp.

I would add something like this... you can then keep it and use anywhere.Attachment 10673

[Beau388]

My suggestion would to use a Coleman Mach 1 PS (11,000 btu) in the rear and a Mach 3 PS (13,500 btu) in the front. The Mach 1 PS draws 9-11 amps and the Mach 3 PS draws 10-13 amps. Even at 95 degrees ambient temps you would only be drawing 19 amps @ 115 volts. Even at 115 degrees your draw would be 24 amps @ 115 volts. I find this setup works well in Texas in the summer in my coach.

[Chance]

Originally Posted by skag101

I have a 98 Windsport. It has two air conditioners but being a 30 amp rv i can only run one at a time. Pretty sure the ones I have are 13,500 BTU. We traveled to FL this spring and the air just didn't cool enough. We usually make two trips a year there.
Would it make enough difference to change to a 15,000BTU ? Cost for the unit is around $700-$800 for a ducted unit. Just wondering if it would make that much difference. What are your thoughts?

Great points have been made already, but in my opinion a little more information is needed.

Is your generator a 4-kW (most likely), and do you ever cool the coach from only the generator instead of shore power?

How big is your motorhome, and how many slides if any?

Are you pretty sure both existing A/Cs are working OK. I’d guess they probably are if you can cool at all with only one at a time, but I’d confirm before sinking money into any upgrade.


I would not spend funds to replace a 13,500 that is working well with a 15,000 if I could only run one at a time. There are other options that should give you better results for the investment (bang for the buck).

[brucev]

The best idea here is to look into upgrading to 50 amp service, something else that may work is to have one of the acs wired to it's own receptical outside the coach and plug in separately when you need it. There was another post by a guy that did that, do a search and ask him how he did it.

[Laco]

I did essentially what bruce describes on my Gemini. Added a second matching roof AC for the front, wired to a separate 30 amp receptacle next to the existing one. I use a Y connector from the two 30 amp receptacles to a single 50 amp cable and just plug into the parks 50 amp service. The only downside to that setup would be the inability to run the front ac with the generator, but while underway, with the dash air I would never need that, and we virtually always camp where electrical is available.

[Chance]

Originally Posted by brucev

The best idea here is to look into upgrading to 50 amp service, something else that may work is to have one of the acs wired to it's own receptical outside the coach and plug in separately when you need it. There was another post by a guy that did that, do a search and ask him how he did it.

Yes, unless he needs to run both off 4-kW Onan, which then may not be enough.

If A/Cs are older like motorhome, they are likely not as efficient as newer A/Cs, and while they will certainly run on 50-Amp service, they won’t run on standard generator. He should expand on expected operation IMO.

[Bob Denman]

I think that I'd upgrade to a pair of more efficient AC unis, and forget about all of the fancy wiring options.

[gmtech16450yz]

Why does everyone think the "newer" a/c's are more efficient? They haven't changed the design in like 30 or 40 years!

If you need better efficiency while driving, you can most definitely improve on the efficiency or amp draw of any RV roof air. Not a whole lot you can do when parked.

[Pete'sMH]

Before doing any of this pull the inside cover off of your existing units and check the baffle. Since both the output and return share a common 14x14 opening the airflow is kept separate by a fiberboard baffle. These things are just friction fit in the housing and many are displaced. Mine was nearly horizontal having been displaced by the wiring. After straightening it up and securing it with metal duct tape the in and out air flow is 100% isolated. It made a HUGE difference in the overall effectiveness. Only takes a few minutes and it’s a good time to clean your filters as well.

[SuperD]

For about $20 you can install a rotating vent in your inside ac cover. Much more air output and you can direct it where you want it. I have dual ac’s and used to run both, after installing the vents I now usually only run one.

[revjeffrey]

The rotating vent made all the difference in the world in our unit. As shown in the photo super easy mod. $8.00 game changer!

[Laco]

Originally Posted by gmtech16450yz

Why does everyone think the "newer" a/c's are more efficient? They haven't changed the design in like 30 or 40 years!

If you need better efficiency while driving, you can most definitely improve on the efficiency or amp draw of any RV roof air. Not a whole lot you can do when parked.

Correct the roof AC's are not at all efficient, compared to what is available for residential. There are limits, since they must run on 120 volts. If efficiency was to be increased meaningfully they would have to run on 220 volts, which is not available from any of the pedestals that I know of in any RV park I have been to.

[gnach]

Originally Posted by revjeffrey

The rotating vent made all the difference in the world in our unit. Ash shown in the photo super easy mod.

3x rotating vent, hands down winner.

[Pete'sMH]

Originally Posted by gnach

3x rotating vent, hands down winner.

Why does the rotating vent help? It’s just right next to a vent opening that already exists.

[revjeffrey]

Max unrestricted cold air flow Floods the Unit. Without seems restricted flow.

[SuperD]

Originally Posted by Pete'sMH

Why does the rotating vent help? It’s just right next to a vent opening that already exists.

The vent mounts directly under the AC blower and reduces restrictions on air flow. The existing vents require the air to make a 90 degree turn into a narrow opening. Having the rotating vent directly under fan increases air output significantly!!!

[Bob Denman]

Originally Posted by SuperD

The vent mounts directly under the AC blower and reduces restrictions on air flow. The existing vents require the air to make a 90 degree turn into a narrow opening. Having the rotating vent directly under fan increases air output significantly!!!

https://www.youtube.com/watch?v=NBh895KdXAU

[Chance]

Originally Posted by Pete'sMH

Why does the rotating vent help? It’s just right next to a vent opening that already exists.

In air conditioning, moving more air doesn’t always help because cooling capacity is limited for the most part by compressor and heat exchangers capacity. Blowing more air across the evaporator will mostly feel good if you’re standing near the vent so it blows on you (like the effect of a fan), but it won’t increase the thermal cooling capacity of an A/C appreciably. The right amount of air is needed to reduce humidity.


The problem here is that we’re missing NEEDED information to diagnose what’s really happening.

Why does a large motorhome have 2 A/Cs if they can only run one? That’s rare.

Even if you can squeeze 5 or 10 percent more out of a 13,500, is that enough? I doubt a vent will help much, but even if it could a little, it’s not enough to cool a large RV with ONE 13,500 or 15,000 A/C. Not in hot humid Florida summer.

In my opinion, the drop-in-a-bucket approach is unlikely to work in this case. We can guess one A/C is in bedroom and other in living room, and unless they are willing to completely segregate RV during day and night, it’s going to be tough to cool with one A/C at a time on a hot humid day. Nighttime should be easy, but 3 PM on a single unit not so much.


Just my 2 cents ....