Can Dometic Ducted AC Unit With No ADB Be Replaced With A Furrion AC With Typical ADB?

Updated 04/24/2026 | Published 04/17/2026

Question:

I have a 2020 heartland big horn with a duck system. There is no box in my ceiling. It’s all ductwork. I would like to get rid of the dometic unit I have a cc thermostat. I do not wish to run wiring. What do you think

asked by: Dan

Dometic Ducted Ceiling Register
(click to enlarge)

Expert Reply:

Hey Dan, thanks for reaching out. So with those ducted AC systems that don't use a typical distributions box, they can only be replaced with an identical AC system. There isn't an easy or clean way to replace it with a Furrion system that uses a typical ADB. So it is possible to replace your AC, but only with another identical unit. That's the only way to keep the ducts, thermostat, and wiring unchanged.

expert reply by: Jesse M

Roger H.

4/24/2026

Not true Jesse, I have replaced both my Dometics with Furrion Chill HE units and added a third. I live in Texas and it gets hot here. I took the coleman coleman conversion kits and drilled holes in the blocks that come in the kit and lag bolted them to the frame of the ac opening in the roof. I placed then upside down so the threaded hole were facing up. Then I drilled out the threaded nuts in the ac unit itself (where the bolts would normally thread in from the bottom) so I could put the bolts in from the top down. My old Dometic didn't have a traditional control box so I had to order a units with a control box and thermostat. The Dometic thermostat is not compatible. I have 3 Furrions on top of my RV now and they keep my place cool even on the Texas Gulf coast. Hopes this helps.

Jesse M.

4/24/2026

@RogerH Oh nice! Good to know there is a way to make it happen even if some modifications are needed. This is very helpful. Thanks for sharing!

Roger H.

4/24/2026

@JesseM If the dometic that is being replaced has the separate control box and not a built in controller, then the wiring harness supplied with the Coleman/Dometic conversion kit should just plug in and not require a new control box and thermostat. I wasn't that lucky and the control box was built into my Dometic AC units. The wiring you need is in place in that case but you have to wire in a new control box and thermostat. The last one I did on my RV was actually the 4th install I have done on these units. I did one on my daughter's rig. We are full timers.

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