Why Are Most Roof Top AC Units Not Compatible w/ a Dometic Duo Therm

Updated 05/22/2025 | Published 05/19/2025

Question:

Why do most of the roof top AC units say that there not compatible with a Dometic Duo Therm? If I am replacing the whole unit does it make a difference?

asked by: Amber H

Expert Reply:

That's because most of them are not compatible, especially if it's a different manufacturer. If by whole unit you mean the AC unit that sits on top and the diffuser box on the inside then no it won't matter. If you're just wanting to replace the AC system, I'll need to know what model it is so I can make sure it's going to work with your air box.

If you could comment below a part number off of your Dometic Duo Therm, I would be happy to recommend a replacement AC unit or entire system if that's what you're wanting to do.

expert reply by: Jerred H

Amber H.

5/22/2025

I have model number 57915.531 and I would like to replace the entire ac unit

Jerred H.

5/22/2025

@AmberH There are no plug in replacements for the Dometic Duo Therm 57915.531, so you'll need to replace your entire AC system. I recommend the Advent Air RV Air Conditioner System item # ADV23SR. This is a 13,500 Btu AC system that includes a new air box, AC unit, start capacitor, and necessary wiring to replace your old Duo Therm.