Looking To Replace Dometic Duo Therm 991721729 AC Unit
Updated 03/24/2026 | Published 03/17/2026
Question:
Hi I’m looking to replace my domestic duo therm 991721729 air conditioner do you know what unit replaces this?
asked by: Austin M
Expert Reply:
Hello Austin, thanks for reaching out. We can help you replace your Dometic duo therm 991721729 AC unit. With that older Dometic Duo-Therm 991721729, there unfortunately isn’t a true plug-and-play replacement anymore. At this point it’s a full system swap, meaning the rooftop unit, ceiling assembly, and thermostat all get updated together. The upside is once it’s done, you’re not dealing with mismatched components or chasing compatibility issues later.
That said, here’s what I’d recommend:
Advent Air RV Air Conditioner System - Single Zone - 15,000 Btu - White - R32 # ADV92SR
This gives you a complete, matched system out of the box so everything works together the way it should. The 15K BTU output is solid, so you’ll have no problem keeping things cool, and airflow is typically better than the older units. It’s designed to work with both ducted and non-ducted setups, so it keeps things flexible depending on how your current system is set up.
As far as install goes, it still uses the standard 14x14 roof opening, so you’re not cutting into the roof or doing anything crazy there. Most of the work is just swapping components and tying into your existing 120V power.
End result, you go from an aging setup with limited support to a clean, reliable system you can count on when it’s hot out, without having to second guess it later.
What RV do you have? Where are you headed after you get the AC up and running?
(click to enlarge)
Ed
3/19/2026
I bought an Advent air in the fall of 24 Works great. A little bit of a bear to install. Once in it worked fine
Jesse M.
3/19/2026
Paul C.
3/19/2026
Hooked up fine never could make heater in camper to work
Dan D.
3/20/2026
Installed one last tear and have been happy with it it was an easy swap out
Jesse M.
3/24/2026
Product Page this Question was Asked From
Advent Air RV AC System w/ Wall Thermostat - 15,000 Btu - Ducted/Non-Ducted - White - R32
- RV Air Conditioners
- Complete AC System
- Cool Only
- 15000 Btu
- Standard Height
- Single Zone
- Rooftop
- Ducted
- Non-Ducted
- White
- Advent Air
more information >
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Austin M.
3/18/2026
So what thermostat and I would need to replace both units correct?