Adding 2nd AC Questions?

[DLM1965]

We have a 2017 Thor Quantum WD31, which comes with a 15,000 BTU AC unit. Not enough cooling for our Southwest heat. There are other threads that address second AC units in general, but I am looking for more specific information. I was told by our dealer that we can add a second 13,500 BTU AC unit, mounted over the rear bedroom, using the existing exhaust fan roof opening. They just pull the existing fan, and drop in what they call a "chute" design AC unit. It does not tie into the existing ductwork - couldn't handle the extra air flow in any case. Rather, a directional chute points the cooling airflow, usually down the center aisle toward the front of the coach. They would add a separate 120-volt circuit to power it, adding an exterior plug-in. They estimated $2,500 turn-key cost. I am interested in thoughts from more experienced RV'ers who may have done something similar.

[blw2]

that pretty much sums up what I've seen other folks post that they've done.

I can't add anything to it really, except to say I sure do wish they made a smaller ac unit...like in the 5,000 to 6,000 btuh range. I feel like that would be just about the right amount of cooling capacity to add, and it wouldn't require the second shore power drop...giving a much neater install IMO. I looked for one a while back toying with the idea of doing it for my 32 Ft. The only thing I found even close was a little unit sold in the european market.

Anyway, I've read posts by others that have done what you are proposing and are happy with it. Hopefully some of them will post here.

Oh, I will add this thought for brainstorming.... if I were going to do this, I think I might look into heating options for the 2nd unit...a heat pump or perhaps a unit with electric heating....just to give another option for heating when I didn't want to run the furnace.

[16ACE27]

Given the cost of a 13.5 BTU AC is under $600,
https://www.amazon.com/Dometic-B5791.../dp/B00SQ2GEJA

they want $1900 labor to do the install?

Wait, maybe only $1800. Gotta account for the extra wire and plug.

[16ACE27]

Or you could add a 9000 BTU mini-split system with heat pump for a few dollars more:

https://www.amazon.com/PIONEER-Air-C...ir+conditioner

[halfprice]

Originally Posted by Tfryman

Given the cost of a 13.5 BTU AC is under $600,
https://www.amazon.com/Dometic-B5791.../dp/B00SQ2GEJA

they want $1900 labor to do the install?

Wait, maybe only $1800. Gotta account for the extra wire and plug.

Plus $100 more for the lower inside unit



Jerry

[halfprice]

Originally Posted by DLM1965

We have a 2017 Thor Quantum WD31, which comes with a 15,000 BTU AC unit. Not enough cooling for our Southwest heat. There are other threads that address second AC units in general, but I am looking for more specific information. I was told by our dealer that we can add a second 13,500 BTU AC unit, mounted over the rear bedroom, using the existing exhaust fan roof opening. They just pull the existing fan, and drop in what they call a "chute" design AC unit. It does not tie into the existing ductwork - couldn't handle the extra air flow in any case. Rather, a directional chute points the cooling airflow, usually down the center aisle toward the front of the coach. They would add a separate 120-volt circuit to power it, adding an exterior plug-in. They estimated $2,500 turn-key cost. I am interested in thoughts from more experienced RV'ers who may have done something similar.

I did exactly what you are looking to do. I did the install with a friend. Took the good part of the morning and afternoon to do.

Getting the ac on the roof and mounting the lower unit to it took about 1 hour.

Running the wire through the wall, under the bed, out the floor, along the frame in conduit, and then to a new 30 amp plug took several hours

There was lunch and a couple breaks also.

Overall not a difficult job to do if you have the tools, which my friend has, and definately not $1500-1800 worth in labor

It works great. I use a 50 amp to two 30 amp dogbone adapter

Jerry

[Beau388]

I highly recommend a Coleman Mach 8 cub or a Mach III PS. Both draw little current. I can run my Mach 15 and Mach 8 cub on the Onan 4000 in the Texas summer heat with no problems If you have a good electric knife, you can cut the Styrofoam to work with the existing ducts, but you will need another thermostat and lower A/C duct work for cut ducts. The Mach 8s have three motors: compressor condenser fan and evaporator fan, so they are quieter than the standard Mach III or Mach 15.

[Long & Winding road]

I agree to what they said above but I dont see any reason that you cant hook it up to the air channels (Ducts) already cut into the foam in the ceiling. They go from the front of the RV all the ways to the back.

They run down the center of the RV so unless your exsiting bedroom vent is off center it should be no problem using this duct work.

Some have used the existing 30 amp power supply to run TWO ac units (but some dont recommend it either .... so do your research first). You can only start one up at a time and maybe allow 10 mintues or so between them on startup.

Plus you could not run both AC units and the microwave (or hair dryer) at the same time (while on 30 amp) so you will have to shut one down for a short time and actively manage your power consumption and count on your other family members or guest to do the same. But this would allow you to run both AC units on your Generator .....otherwise with the way you mentioned abouve the 2nd unit could only be plugged in at the camp ground.

If you could switch back and forth (both on 30 amp and run on Genny, then when at camp ground split the system like you mentioned) that would be the best of both worlds?? That wouldnt be that hard to do (IMO).

Something to think about anyway.

[halfprice]

On the 29m the rear vent is already set up to be ducted. Just need to buy a ducted ac unit

i didnt want to use the ducting. When we are at a temp we like We found the bedroom ac will keep the entire coach cool. Plus the noise level in the living room is low. At night we switch that. Living room keeps bedroom cold without the noise. Works great and neither ac is over worked

Jerry

[Ron1Z]

I just started doing the wiring for my second A/C unit in the bedroom yesterday and will finish it today.
Still waiting for the Mach 15 to arrive. I went with the 15 because it is the same as the front A/C unit, I also ran a seperate 20 amp circut for the rear A/C unit.
Coleman Mach 15 = 654.00 (includes delivery)
Inside grill for unit -54.00
optional electric heater = 29.00
Wiring, plug, etc = 50.00
Total= 787.00 All parts came from ebay. Electrical from Lowes

After I get unit installed then I want to take the Fantastic fan that I removed and swap it out with the cheep fan in the bathroom.

[The Gritz Carlton]

This will turn into a huge thread so I'm in real quick and out with my .02. Your initial suggestion is the best, most simple way to go. The choice is whether you DIY or pay the dealer. Write the check and don't look back. The ducting in some of the bigger units is not foam. I saw this during my factory tour. The "looped ducts" in my 35' are made/welded into the aluminum frame as a closed unit. Yours may be this way also. For the most part, one A/C will work but for the heat of the day, plugging into a second 120V wouldn't be much of a problem. It would also give you the option of using that unit with a small table top fan instead of the factory 15K, eliminating the need for 30/50A service. In some boondocking situations, you could use a small inverter generator to run the added unit like the Champion 3100 or 3400. Or, in circumstances (family driveways) you can just plug in to a 120V outlet and have A/C. Your initial idea gives you the most power options...I'm all about options. There's so many options here and tons of knowledge...mostly validated. Personally, Thor should never build a MH over 28' without pre-wired options for 2 A/C's.

[Long & Winding road]

Well im waiting for this new Proair 12v, 20K BTU AC to hit the market!!

Check out youtube, RV fit and look for "Interesting Finds on our Coachmen Class B Factory Tour!". Fast forward to around 13:50.

I dont know how to post links yet.

https://www.youtube.com/watch?v=4T3vTdoKBiA

12volt!!! Very quiet, 50 - 60 amp of power needed?, serviceable (not a throw away unit like the Colman).

This could be the answer for most of us. Wont have to run the gernerator while driving down the road to keep the whole RV cool. Should be able to run a few hours with a couple of batteries? They said an "additional 2 hours with lithium".

[Beau388]

Originally Posted by The Gritz Carlton

Personally, Thor should never build a MH over 28' without pre-wired options for 2 A/C's.

Prior to Jan 2017 Thor Motorcoach did not offer two A/C in any coach under 32 feet. After Jan 2017 any plant 750 coach could be be ordered with 50 amp power center, 5500 Onan and and second A/C for $6,600 dealer cost. The reason - cost and the fact that most of the class A of less than 32 feet do not need a second air conditioner 95% of the time unless you live in the 9 most southern states. Even then one A/C works well if you are camped under a tree or running the engine A/C.

[The Gritz Carlton]

Originally Posted by Beau388

Prior to Jan 2017 Thor Motorcoach did not offer two A/C in any coach under 32 feet. After Jan 2017 any plant 750 coach could be be ordered with 50 amp power center, 5500 Onan and and second A/C for $6,600 dealer cost. The reason - cost and the fact that most of the class A of less than 32 feet do not need a second air conditioner 95% of the time unless you live in the 9 most southern states. Even then one A/C works well if you are camped under a tree or running the engine A/C.

Depends on how well insulate you are. Plus, whether you live in the 9 most southern states or not, probably 90% of all RV's make it here at one time or another for extended stays. One day down here without adequate A/C will start divorce proceedings. From what I read, most Class A's need generators running all day while underway to keep things comfortable, as the dash unit is worthless.

[Beau388]

Originally Posted by The Gritz Carlton

Depends on how well insulate you are. Plus, whether you live in the 9 most southern states or not, probably 90% of all RV's make it here at one time or another for extended stays. One day down here without adequate A/C will start divorce proceedings. From what I read, most Class A's need generators running all day while underway to keep things comfortable, as the dash unit is worthless.

Never had a problem with a 30 amp coach traveling in the spring or fall through the US and Canada for 17 years when we were living in Western Kentucky. I did get trapped in Topeka the first week of August during a 108 degree heat wave. We found a tree at a campground and waited it out until midnight and then headed back to KY. Moving to San Antonio, TX 18 months ago, it became evident to spend any time in West and South Texas from June through September we need two A/C, as the heat is oppressive and trees big enough to shade a coach were seldom found.