RV A/C Mod - custom duct routing layouts

The problem: 

From the factory, RV A/C units aren’t directly connected to your vents. Instead, they dump cold air into a hollow ceiling space (the plenum) and hope it finds its way to the ducts.

• Air swirls and escapes inside the plenum

• You lose air pressure

• You lose cooling efficiency

That’s why your vents often feel weak, even when your A/C is running at full power. From the factory, RV A/C units aren’t directly connected to your vents. Instead, they dump cold air into a hollow ceiling space (the plenum) and hope it finds its way to the ducts.

Important Note:
This model provides individual airflow adapter components only.
It does not include ducting and does not prescribe any specific airflow configuration.
Users are responsible for designing and installing their own ducting or tubing solutions appropriate for their application.

This model consists of modular airflow adapters intended for custom HVAC experiments and user-defined layouts. The adapters are designed to interface with a variety of vent sizes and ducting types, allowing users to configure their own solutions based on individual installation needs. This is not a complete HVAC system or plenum assembly.

Works on the Dometic, Coleman, Furrion, and others. Increases airflow, whisper-quiet RV A/C Mod. Requires ducts; non-ducted ACs are not supported. 

Suggested material: ABS or PETG for temp stability.  No supports are needed when printing (supports are needed on short-depth vent adapters). 

Print settings: 3 walls/15% infil. 

Unmatched Vent Compatibility
Unlike competitors who limit their designs (dragonfly2.net, rvairflow.com, etc), I support every vent size possible.

This is also the only component solution that doesn't require insertion inside the A/C output, offering a cleaner and more efficient installation.



Supported Models *models in testing

Dometic

• Brisk II

• Brisk (original)*

• Fresh Jet

• Duo-Therm (use Brisk II file)

• Atwood

• B579/ B595/ B591/ 520/ 540

Coleman/Airxcel

• Mach 1

• Mach 3

• Mach 3 Plus*

• Mach 3 Roughneck*

• Mach 8*

• Mach 8 Plus*

• Mach 10

• Mach 15

• Mach 15 Roughneck*

• Q

• Marine

• Maxxair Mach series* - - use coleman mach 8 file

• All Airxcel models*

Furrion

• All models including the 13SA, 14SA, or 15SA

GE/Recpro

• All GE models*

• GE Low Profile models

• Recpro 13.5K/15K*

Update log:

Dec 2025
Instructions updated

August 2025
New - Coleman Mach Series 6"x5.3" with 4" depth

Updated all models. If you've downloaded any models before Aug 2025, get the new files fixing angles, printing quality, and dimensions

July 2025
Testing GE Low Profile Models!
Added 2.75x7 Vent
Added Dometic Brisk Original/Duotherm non-hole version
Added Furrion 13S 14S 15S version 3
Updated supported list

April 2025
Added new Dometic II angled vents for Dometic installs with vents in front vs to the sides

March 2025
We now support the Furion 13SA, 14SA, and 15SA!! - the world's first to support these models
Added a 20° angled Coleman Mach 1, 3, 10, 15, Q, and Marine Y-Splitter for tighter spaces

Jan 2025
Added 2x8 short vent adapter
Added 2.75x8 short vent adapter

Aug 2024
Added Dometic Fresh Jet beta support
Added short-depth vents for extremely tight spaces, used rarely. 
Added 2x6 vent adapter

July 2024
Added Coleman Mach 1, 3, 3 plus, 3 Roughneck 10, 15, 15 Roughneck, Q, and Marine beta, Version 2 files
Added Furrion beta Version 2 file
Added GE Appliances beta Version 2 file
Added version 4 vent adapters with smoother adapter edges.
Added version 4 wider vent version for 7 ¾" wide vents
Added Single splitter beta file for Dometic - comment request
Added Coleman Mach 8 plus and partial-brim beta file
Added Dometic Brisk One (the OG) beta file - comment request
Added Coleman Maxxair Mach series beta files

June 2024
Published
 

Items you will need for installation:

• Foil Tape

• Philips screwdriver

• 10mm socket and wrench (for the cover bolts)

What files to use?

Most vent sizes are 1.5" X 7".  Measure your vents.

Full Brim vs Partial Brim profile: The brim for taping is missing on one side of the “Partial Brim” version for fitting in spaces where vents are close to the edge. 

For vents that are less than 6" away from the cold air output, use the “Low Profile” version

Choose the Y-Splitter for the make/model of your A/C

 

Step 1: 

Remove the AC cover, air filter. Pay close attention to the power box and any connecting wires; use care not to pull on anything or put tension on temperature control wires. 

Take pictures. Document the “before” for re-installation. 

Remove the screws holding the filter assembly on. 
 

Remove the steel bracket holding the power box. Remove the screws holding the power box in, let the box hang under the weight of the wires; use care not to pull on the wires. 4x 10mm bolts hold the steel bracket to the AC. 

Coleman example:
 

Step 2: 

You may need to remove the air dam to install the Y-splitter - this may be a foam piece or metal separating the hot intake and cold output. 

Coleman example Air dam: 
 

Step 3: 

Once everything is removed, close up any gaps in the vent openings with foil tape. Seal any opening, gap, hole, etc that could let cold air or hot air not be directed properly. 

 

Step 4: 

Install the Y-Splitter. Note that the Y-splitter is shorter on one side. Place the shorter side of the Y-Splitter on the side with limited space.  



 

Use foil tape to seal around the y-splitter, ensuring a good seal. 
 

Step 5: 

Install the vent adapters. They should be printed in "mirror" on the slicer, ensuring alignment with the Y-Splitter. 

Ducting, tubing, and airflow routing methods are not included and are intentionally left to the user to accommodate different vehicles, layouts, and preferences.

Use foil tape, ensuring a good seal. Tape will keep it secure and seal it from air leaks. 

  

Step 6: 

Reinstall brackets, secure power cables, boxes etc, exactly as you found it. The air dam or separator does not have to be reinstalled. 

Designed as a modular, non-integrated adapter solution, allowing users to design their own airflow paths without modifying the air conditioner’s internal assemblies.

Original Design - verified by Prusa Research content specialists in Aug 2024
This is an entirely original work and design, inspired by the original work of Simon Leung. While other products on the market may look similar (rvairflow.com, koolrv.com, dragonfly2.net), this is the only solution available for the Coleman Marine series, Mach Plus, Mach low-profile, Mach Roughneck, Furrion 13,14, & 15SA, and now the GE Low Profile models. Additionally, Layers For Life LLC is the only provider worldwide offering single-vent solutions.

You shall not share, sublicense, sell, rent, host, transfer, or distribute in any way the digital file or 3D printed versions of this object, nor any other derivative work of this object in its digital or physical format (including remixes of this object).