Can Mini Splits be Installed on Interior Walls?

Mini-split air conditioning systems have become increasingly popular in recent years due to their flexibility, energy efficiency, and ease of installation. One common question that arises is whether these systems can be installed on interior walls. The answer is yes, mini-splits can be installed on interior walls, but it requires careful planning and consideration of several technical factors.

Line-set Run to the Outdoor Unit

The line-set, which consists of the refrigerant lines and electrical wiring, must be properly routed to connect the indoor unit to the outdoor unit. This can be achieved in two ways:

  1. Concealed Line-set Run: The line-set can be run within the wall cavity to the exterior where the outdoor unit is located. This requires cutting a hole through the interior wall and carefully routing the line-set through the wall. Proper insulation and sealing are crucial to prevent air leaks and maintain the thermal efficiency of the system.

  2. Considerations: Ensure the wall cavity has sufficient space to accommodate the line-set without compromising structural integrity. Coordinate with a professional to determine the optimal routing path and size of the wall penetration.

  3. Tools Required: Stud finder, drywall saw or rotary tool, insulation, sealant, and line-set cover or chase.

  4. Exposed Line-set Run: Alternatively, the line-set can be run externally along the wall to the nearest exterior wall or directly to the outdoor unit. This approach is often more straightforward but may require additional aesthetic considerations.

  5. Considerations: Ensure the line-set run is secured properly and protected from physical damage. A decorative line-set cover can be used to conceal the exposed line-set and maintain a clean, finished appearance.

  6. Tools Required: Level, drill, screws, anchors, and line-set cover or chase.

Regardless of the line-set routing method, it’s essential to follow local building codes and manufacturer’s instructions to ensure a safe and compliant installation.

Condensate Management

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Proper condensate management is a critical consideration when installing a mini-split indoor unit on an interior wall. Condensate, the water that collects during the cooling process, must be effectively drained to prevent water damage and maintain the system’s efficiency.

  1. Gravity-Assisted Condensate Drainage: If the indoor unit is positioned near an exterior wall, the condensate can often be drained using gravity. The condensate line can be routed through the wall and outside, where it can be directed to a suitable drainage area.

  2. Considerations: Ensure the condensate line has a consistent downward slope to facilitate efficient drainage. Avoid any low points or traps that could cause water buildup.

  3. Tools Required: Drill, PVC or copper piping, fittings, sealant, and insulation (if necessary).

  4. Condensate Pump: If the indoor unit is located farther from an exterior wall, a condensate pump may be required to actively remove the condensate. The pump can be installed near the indoor unit and connected to a drainage line that leads outside or to a designated drainage area.

  5. Considerations: Ensure the condensate pump is properly sized for the system and installed according to the manufacturer’s instructions. Provide a dedicated power source for the pump and consider backup power options in case of power outages.

  6. Tools Required: Condensate pump, PVC or copper piping, fittings, sealant, and electrical wiring components.

Proper condensate management is essential to prevent water damage, maintain system efficiency, and comply with local building codes.

Access for Line-set Connections

When concealing the line-set within the wall, it’s crucial to provide easy access to the connection points between the indoor unit and the line-set. This allows for future maintenance, repairs, or modifications without the need to cut open the wall.

  1. Access Panels: Strategically place access panels or hatches at the line-set connection points. These panels should be large enough to accommodate the necessary tools and provide sufficient clearance for technicians to work.

  2. Considerations: Ensure the access panels are easily accessible, well-sealed, and aesthetically pleasing. Coordinate the panel size and placement with the overall design of the space.

  3. Tools Required: Drywall saw or rotary tool, screws, sealant, and access panel or hatch.

  4. Removable Wall Sections: In some cases, it may be possible to create a removable wall section or panel that can be easily taken down to access the line-set connections.

  5. Considerations: Ensure the removable section is securely fastened and can be easily removed without compromising the wall’s structural integrity or appearance.

  6. Tools Required: Drywall saw or rotary tool, screws, sealant, and framing materials (if necessary).

Providing easy access to the line-set connections simplifies future maintenance and repairs, reducing the need for invasive wall modifications.


In summary, mini-split air conditioning systems can be installed on interior walls, but it requires careful planning and consideration of several technical factors. The key aspects to address are the line-set run to the outdoor unit, condensate management, and access for line-set connections. By following best practices and adhering to local building codes, homeowners and HVAC professionals can successfully install mini-splits on interior walls, ensuring a functional, efficient, and aesthetically pleasing system.


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