Replacement AC System for a Dometic Duo-Therm Penguin model 620526.321
Updated 09/08/2026 | Published 09/02/2026 >
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Question:
Needing to replace a Duo-Therm 620526.321 on a Prevost Featherlite conversion. I would like to use the old controller if possible. Recommendations?
asked by: Bart S
Expert Reply:
Welcome back Bart, and thanks for the information! To replace your 13,500 btu Dometic Duo-Therm Penguin model 620526.321, I recommend the Advent Air RV Air Conditioner System item # ADV87QR for a ducted setup or item # ADV77QR for a ductless orientation.
There's no way to just replace your Dometic AC unit and reuse your old controller, you'll need to replace all your AC system components. This is due to the EPA changing the regulations on the refrigerant in the AC units at the beginning of 2025. They've been upgraded to R32 and your Dometic Duo-Therm has the now obsolete 410a refrigerant. None of the 410a components are compatible now with the newer systems. You will be able to use the existing wiring to power the AC system and connect the new thermostat if yours has one.
The Advent Air item # ADV87QR is a 13,500 btu system that includes, a white AC unit, an air distribution box for a RV with air ducts, and a new wall mounted thermostat. The louvers on the air distribution box can be opened to allow air to vent directly from it. This kit is also available with a black AC unit item # ADV59QR.
If you decide to go with one of the ducted Advent systems, I highly recommend picking up the Bluetooth Remote Controller for Advent Air RV Air Conditioner Thermostat item # ADV67QR. It'll allow you to control the settings on the thermostat from anywhere in your RV.
The Advent Air item # ADV77QR is also a 13,500 btu system that includes, a white AC unit and a air distribution box that is designed for ductless layouts. The controls are built into the air distribution box so this system does not include a thermostat. This system is available with a black AC unit as well item # ADV27QR.
What area or room in your Prevost are you replacing the AC? Feel free to answer this and throw in any other questions you have, where it says Add Comment.
Product Page this Question was Asked From
Advent Air RV Air Conditioner System - 13,500 Btu - Single Zone - Ducted - White - R32
- RV Air Conditioners
- Complete AC System
- Cool Only
- 13500 Btu
- Standard Height
- Single Zone
- Rooftop
- Ducted
- White
- Advent Air
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Bart S.
9/8/2026
it's the forwardmost unit of the 3 roof airs that has failed. It is a ducted system. and I am contemplating replacing all 3 units for uniformity. Is there a blue tooth system that can control all 3 from 1 laptop or smart phone? Also. I'm thinking 15,000 btu each.