Hide Internal AC Units (Custom Louvered Cabinets)
A custom louvered cabinet can make an indoor AC unit less visible, but it must not restrict the unit’s airflow, drainage, controls, or service access. Start with the exact model’s installation instructions, then size and place the enclosure around its requirements. A removable, independently supported cabinet is only suitable if the manufacturer permits it and testing confirms normal operation.
An indoor unit can interrupt a carefully planned room, especially when it sits on a prominent wall. A tailored cabinet may soften its appearance, but a grille that looks open can still restrict airflow. The design challenge is to hide the equipment without making it harder to run, clean, or repair.
I plan the cabinet around the AC, not the other way around. That means confirming the model’s requirements before choosing the cabinet depth, louver layout, finish, or hardware. There is no universal clearance or louver size that works for every unit.
Plan around the exact AC model
Before drawing a cabinet, identify the unit and read its installation and service instructions. Those documents set the requirements for clearance, airflow, filter removal, and access. Local rules also matter: adopted code and amendments may differ by location, so confirm them with the relevant building authority.
Find the unit’s instructions
The model number is the starting point for a safe design. Look for the nameplate on the unit or check the owner’s documents. Use the installation and service manuals for that exact model, not a manual for a similar-looking unit.
The governing principle is to follow the equipment’s listing and instructions. IRC M1307.1, IMC 304.1, and NEC 110.3(B) address installation in line with manufacturer requirements, subject to the editions adopted locally. These references do not create one set of cabinet dimensions for all AC units.
Record the required clearances at the top, sides, and front. Also note where air enters and leaves, how the filter comes out, and which covers or connections need service access. If the instructions do not explain whether an enclosure is allowed, ask the manufacturer or a qualified HVAC professional before building.
Map airflow and service access
A louver is a grille made of angled slats that lets air pass while screening a view. Its visible face size does not tell you how much air can flow through it. Check the louver maker’s published net free area, meaning the area actually open to airflow after the slats and frame are accounted for.
Mark the unit’s intake and discharge on a simple elevation or sketch. Then show the filter-removal path and the space needed to reach service panels, electrical covers, drain connections, and controls. The cabinet must not push on the unit, pipes, or wiring.
Size the louvers and preserve clearances
A cabinet’s air openings must match the AC’s actual airflow needs and path. Use manufacturer data for the required airflow and permitted inlet-face velocity; do not guess a louver percentage. Keep the intake and discharge separated as the manual requires, so discharged air does not loop back into the intake.
Calculate net free area
If the AC manufacturer provides the required airflow, Q, and maximum permitted inlet-face velocity, V, calculate the required net opening area with this formula:
A = Q ÷ V
Use consistent units. For example, if airflow is stated in cubic feet per minute and velocity in feet per minute, the result is in square feet. Then check the louver’s published net free area, not just its outer dimensions. If either Q or V is missing, request guidance from the AC manufacturer or a qualified HVAC professional rather than filling in a value.
| Design item | What to verify | Why it matters |
|---|---|---|
| Cabinet clearance | Model-specific top, side, and front minimums | A general rule cannot replace the manual |
| Louver area | Published net free area | Face size may overstate the air opening |
| Air path | Intake and discharge direction and separation | Prevents blocked flow and air recirculation |
| Filter access | Full removal path with cabinet open | Allows routine cleaning without dismantling the AC |
| Service access | Required space at panels and connections | Keeps inspection and repair practical |
Avoid short-circuit airflow
Short-circuit airflow occurs when air leaving the unit gets drawn back into its intake. A cabinet can have a large grille and still cause this problem if the openings are poorly placed or the interior is too tight. It may affect performance or lead to abnormal operation.
Lay out the grille to serve the actual intake and discharge locations. Do not assume one large opening will work for both. If the manual does not show a permitted cabinet arrangement, get manufacturer guidance before proceeding.
Build a removable, independent enclosure
The cabinet should be supported by its own framing, not by the AC unit, its drain, or its refrigerant lines. Use removable panels where needed for cleaning and service. Keep all framing, finishes, and fasteners outside the clearances listed for the exact model.
Support the cabinet without loading the unit
Plan the frame and fixings so that the enclosure stands independently. The AC should not carry cabinet weight, and the framing should not pinch pipes or the condensate drain. A condensate drain carries water away from the unit; its route and connections must remain protected and serviceable.
Use a rigid access panel that can be removed without shifting the equipment. Choose fasteners that are easy to reach and suited to the cabinet construction, but do not assume a universal hardware load rating applies. If the proposed design depends on an unusual support or attachment, have it reviewed by an appropriate building professional.
Keep access practical
A cabinet is not truly functional if it hides the filter or blocks a service cover. Before finalizing the design, confirm that the filter can come out along its full path and that a technician can reach the required panels and connections.
Keep controls and sensors visible or usable as the manufacturer specifies. Do not conceal electrical connections that must remain accessible, and do not route cabinet parts across the unit’s service area. A hinged or removable front can help, but only if it opens far enough to provide the access the manual calls for.
Learn from two cabinet design scenarios
These scenarios show how the same design goal can lead to different decisions. They are planning examples, not measurements or performance claims for a particular AC model. In both, the exact unit instructions determine whether the proposed enclosure can proceed.
Scenario: a wall unit with a front intake
A homeowner wants a shallow, painted cabinet to blend with a feature wall. The first design places a solid panel close to the unit, with a decorative grille across the front. Reviewing the manual reveals that the filter needs a clear removal path and that the unit requires specific space at its front.
The cabinet is revised to provide that space and a removable front. The louver layout is checked against published net free area and the manufacturer’s airflow details. If those details cannot confirm a suitable opening, the homeowner pauses the build and seeks guidance rather than relying on the grille’s appearance.
Scenario: a unit near a corner
In another planning scenario, the unit’s discharge points toward a nearby return path that could send air back toward its intake. Adding side panels may make the cabinet look more finished, but could also worsen recirculation or reduce access to connections.
The design review maps intake and discharge before choosing the panel layout. The cabinet proceeds only if the manufacturer’s requirements can be met and the drain, electrical access, and service panels remain reachable. If not, a less enclosed treatment may be the better solution.
Test the cabinet before calling the job complete
Commissioning means checking the equipment in its finished installation. Test with the cabinet closed, since that is how the unit will normally operate. Compare its operation with the enclosure open or removed where practical, and investigate any clear change in airflow, noise, vibration, or drainage.
Check operation and service access
With the cabinet closed, run the AC in the relevant operating modes. Look for blocked airflow, signs that discharge air is returning to the intake, unusual noise or vibration, and condensate leakage. Stop and seek qualified help if operation appears abnormal; a unit running is not, by itself, proof that the enclosure is suitable.
Then open or remove the access panel and confirm that the filter, electrical covers, drain connections, and service panels can be reached as required. Repeat the check after any cabinet adjustment. Keep the installation and service instructions with the project records.
Conclusion and frequently asked questions
A well-planned louvered cabinet can reduce the visual impact of an indoor AC unit while preserving its function. The reliable path is to identify the exact model, design from its instructions, use verified louver free-area data, and test the finished enclosure. If any requirement is unclear, pause and ask the manufacturer or a qualified professional.
Can I put an indoor AC unit inside a cabinet?
Only if the manufacturer’s instructions permit the arrangement and the cabinet preserves required clearances, airflow, and service access.
How much clearance does an AC cabinet need?
There is no universal clearance. Use the minimums listed in the installation manual for the exact model.
How do I size cabinet louvers?
Use the unit’s airflow requirements and permitted inlet-face velocity to calculate net opening area. Check the louver maker’s published net free area.
Is the louver’s face size its free area?
No. The frame and slats reduce the open area. Use the published net free area, not the grille’s outer dimensions.
Can one grille serve both intake and discharge?
Do not assume so. Follow the unit’s airflow path and separation requirements to avoid blocked flow or recirculation.
Can I use a solid cabinet door?
A solid door may block airflow when closed. Use an arrangement approved for the model, and keep required openings clear during operation.
Does the cabinet need to be removable?
The enclosure must allow the access required for filter removal and service. Removable panels can help, but their placement must suit the unit.
Can I attach the cabinet to the AC unit?
Do not use the AC as cabinet support. Build an independent enclosure that does not load the unit or pinch its piping or drain.
What if the manual does not mention cabinets?
Ask the manufacturer or a qualified HVAC professional whether the proposed enclosure is allowed. Do not infer approval from a similar model.
How do I know the finished cabinet works?
Test the unit with the cabinet closed. Check airflow, recirculation, noise, vibration, drainage, and access. Investigate abnormal operation before accepting the design.
(This article was written by one of our staff writers, Michael Donovan. Visit our Meet the Team page.)
