Air conditioning advice

[CarlV]

I have a 2019 Thor Four Winds 31E. Last summer, coming back from the west coast we stopped overnight in OK. The first week of July. It was HOT. The AC unit was a joke. It barely kept the camper at 80. It has worked fine since in less extreme temperatures. I am pondering replacing it with a 15k BTU unit. (Currently is 13.5k original, unsure of brand). Do I add another 13.5k unit in the bedroom? This would be wired to run off of shore power by a 15amp circuit and not connected to the 30amp shore power. Or I could install the old 13.5k unit in the bedroom and a brand new 15k in the kitchen.
Just looking for advice from people that have added a second unit to their rigs.
Thanks in advance!

[CarlV]

Update, I have a Coleman Mach unit, 13.5btu currently installed in the kitchen.

[WarHorn79]

I'm looking to add a 2nd unit but might replace the original due to the age and overall look versus waiting to see it fails. Thinking about 2 13.5 BTU units for the lower amperage draw and sound. I think it depends on do you think you'll run the 15k and just use the 13 to supplement or run both normally.

I have ductless so anticipating running both simultaneously at a moderate rate since the wife gets cold. With both running I don't think I need one unit bigger than the other but I guess could also be good if one fails.

[TandW]

Years ago I added an AC unit above the bedroom in the Allegro 31IA. Never had a problem running both units at the same time. But when I did run them at the same time the fan speeds were kept on low. This with 30 amp service onboard. Of course, nothing else could be running at the same time. No electric hot water, microwave, toaster, or electric skillet. No, no, no!

[Mudfrog]

Looks like the OP's rig is around 32 feet in length, has a full wall slide, and a 7 foot high interior ceiling. That's a lot of cubic feet to keep cool.

Our 28 foot fig with small slide has a 14.8k btu unit that does ok in lower 90s temps but struggles when temps get closer to the century mark. Imo, two 13.5s would be the way to go.

[2cyber71]

A 30 amp circuit will run 2 13.5BTU units.
But, remember if you turn on the microwave or electric hot water it will shed a AC.

I have a. 50 amp all electric RV with 3 AC
If they are all running on high, in hot weather it will shed the AC if I turn on my induction cook top, my microwave, my washer and dryer or if my electric hot water kicked in. So if you’re in hot weather and want to do the wash, be ready for a warmer RV.

[TXiceman]

Frankly, that size RV needs two 13,500 BTUH units to survive summers in the south and west. Those units are poorly insulated and need lots of A/C.

Alternates to keeping cool are parking in the shade and/or keeping the sun off the sides and windshield. Putting up a layer of Refltix in all the windows will help a bunch. Also adding solar screens to the outside of the windows will help.

By going to a 15,000 BTH over the 13,500 BTUH unit you will pick up 1.500 BTUH more capacity which is not a lot.

I would look at adding a second 13,500 BTUH unit that is high efficiency and putting soft-start kits on both of them. You may get by running them both if you watch the energy usage and not run the microwave, keep the water heater and fridge on gas (not electric).

Ken

[twinboat]

Originally Posted by TandW

Years ago I added an AC unit above the bedroom in the Allegro 31IA. Never had a problem running both units at the same time. But when I did run them at the same time the fan speeds were kept on low. This with 30 amp service onboard. Of course, nothing else could be running at the same time. No electric hot water, microwave, toaster, or electric skillet. No, no, no!

First you say you never had a problem running 2 A/Cs, then you list all of the problems with doing it.

" Of course, nothing else could be running at the same time. No electric hot water, microwave, toaster, or electric skillet. No, no, no..."

[SteveJ.]

A Houghton from RecPro or a Dometic Atwood Air Command would be good A/C units to consider as they draw less current than others, have their own control setups, and they are much, much quieter. I installed an Air Command 13.5K about a year and a half ago in our Trek. It works a treat. And did I say it was/is quiet?

There are cheaper units out there but you do get what you pay for, usually.

[ChrisDParise]

I've got a 30.5' Class C with 1 13.5 AC. Your inside air temp is about right for 100 degrees outside.

I have a couple tiny office fans I use to move air in and around the rear bedroom. I don't always use them.

Last year I bought a cordless fan that nicely hangs from the bedroom doorway header and its adjustable to point right at the bed. Has more than enough battery to run all night before needing a recharge and it's quiet.

I like your plan on the 2nd 15 amp circuit for the added bedroom ac as long as you have shorepower. Ac noise right over the bed would need getting used to but I require fan noise to sleep the best anyway.
There are some detailed plans out there on adding a bedroom ac that way which is always a plus.

[TandW]

Originally Posted by twinboat

First you say you never had a problem running 2 A/Cs, then you list all of the problems with doing it.

" Of course, nothing else could be running at the same time. No electric hot water, microwave, toaster, or electric skillet. No, no, no..."

I can take a cheap shot now and then. Sorry you've forgotten about power management. Something seasoned RVers practice out of hand.

[edge68474]

[Cassy]

Definitely start with the windows reflectix &/or black curtains

[Capt Steve]

If you are getting 20 degrees of cooling that is about as good as it will get unless you employ additional cooling techniques {shady parking, DC fans additional insulation/Reflectix etc.}. A 32 foot Class C with just one 13.5 BTU AC is seriously under cooled especially with large slide{s} and you should wonder what else the manufacturer cheaper out on.

If you have a gasser you have the additional option to run your dash air {which typically has more cooling than your roof unit} while the coach idles {don't try this with a diesel}.

After 9.5+ years of living in Arizona and doing a 2 month cross-country trip the worst heat we have ever had to endure was in southern Illinois {in June} hiding out from the tornados in a small park carved out of the cornfields. Even running the dash air along with our 13.5 roof unit {24' Class C} was no match for the brutal humidity and near triple digit temps.

When the higher summer temps arrive here in Arizona we just head to the higher elevations for relief as anything above 6 to 9,000' typically will not necessitate AC which is a nice option to have.