Second ac unit - ducted or not?

[Gloftis55]

My new hemisphere 356QBQ just doesn't stay cool throughout with only the one 15000 BTU unit. Having 2nd ac unit put in the front bdrm. My question is should I have it tied into my present duct system and add a second thermostat or just let it be a free flowing roof unit ? My dealer recommends it may not be worth the extra couple of hundred bucks to have it tied in to the present system, but it seems like being ducted in with the existing unit that it would really increase the air flow throughout the entire unit versus just in the bedroom. It was mentioned at the dealer ( in for some minor warranty fixes/ adjustments) that if I left the bedroom door open that the cold air would flow down through the unit. Any thoughts or recommendations from anyone who has installed a second unit either way? Thanks

[dcheatwood]

Pros and cons either way. I was pleasantly surprised to learn that I can run bedroom ac while in the living room and run lr ac while sleeping. Much quieter that way and both units blow thru all vents. Use both to cool down RV faster.

[Steelframer]

The problem with having them both tied into the duct work is that it may not have been designed for two units, so when running both through the ducts it may not be able to push enough volume of air through and your AC units may freeze up. Pros. Like the other poster stated you can run the opp. Unit and it won't be as loud. Or you can dump one while ducting the other if both are needed to cool the TT.

[dcheatwood]

And you can close the vents you don't need to force more air where you want it.

from David's RAZR M.

[jtstromsburg]

I added a 2nd ac to our sabre and ducted it. Love it. As said earlier, when we are in the lr, we can just have the front ac running and it's much more quiet. Course when it's really hot, both run and keep it cool easily. We've been in direct sunlight, 100°, and kept the inside at 72 with both units cycling on and off.

[1l243]

I added a non ducted to the garage of the toy hauler. It was prewired for ac but not ducted. I did it myself did not even consider ducting it. I like being able to close off the garage or in your case the bedroom and have the non ducted AC just for that space.

[BigJohnD]

Thinking about adding a third to ours, and debating to duct or not to duct. 2 just don't keep up in this 40 footer. At least not to my likings. It's been 90-95 on occasion, and you might see 74 in the living room. I still have a few more mods to do for improvement before I take the plunge on a third. Only have 2 ducts in the biggest room (living room). I've added deflectors in each AC to direct the air flow directly into the ducting. This improved air flow. Added scoops to the living room ducts. Definitely helped. Now going to add 2 more outlets in the living room, and baffle off the ends of each duct. Then, we'll see how it does. The "circular" duct system cedar creek does makes no sense at all.

[1l243]

If adding a thrid AC check the amp rating. Assuming you have 50amp service. You may not be able to run all three at the same time but you could be more selective on where and whch ones you run...

[BigJohnD]

You can, but I'd probably only add a polar cub or something like that in the bunk house. Was also considering putting the third on it's own box with 30 amp marinco inlet on the rear. I've seen a few threads and pictures of that. They just utilized the 30 and 50 amp plugs at the CG. Think it was on the Sierra / Sandpiper.