Clean walls. No ceiling chase. Just the diffuser shows.
Bulkhead systems hide the indoor air conditioning unit inside a plasterboard soffit — typically above a hallway or wardrobe — and deliver air through a slim linear diffuser flush with the ceiling. The architectural middle ground between a visible wall split and full ducted reverse cycle.
Installed bulkhead system
The bulkhead reads as part of the ceiling architecture — only the slim slat grille gives it away. No wall presence, no visible equipment, no compromise on the room.
Three levels of visibility — bulkhead is the middle ground
Air conditioning has three main visibility tiers in a residential setting. Each has trade-offs around cost, install complexity and how much the equipment shows in the room.
Wall split
Indoor unit mounts directly on the wall. Lowest cost, easiest install, but always visible. Best for single rooms where wall presence isn't an issue.
Bulkhead
Unit hides in a plasterboard soffit, usually above a hallway. Only the slot diffuser shows. Cheaper than full ducted, much more discreet than a split.
Fully ducted
Equipment lives in the ceiling cavity, vents flush with the ceiling. Whole-home coverage, highest install cost, requires accessible ceiling space.
It's the right answer when two things are true
Bulkhead systems shine in specific situations. If both of these apply to your home or project, this is usually the format we'd recommend.
You want clean walls
A wall split unit would be visually intrusive — open-plan living, hero rooms, designer interiors, or any space where you'd rather not see a plastic box mounted at eye level.
Ducted isn't practical
Full ducted reverse cycle needs accessible ceiling space and is the most expensive option. If the ceiling cavity is shallow, the house is single-storey on a slab, or budget is tighter, bulkhead is often the better fit.
You're already building or renovating
Bulkheads need to be designed into the build — they're not a quick retrofit. If you've got walls open and ceilings accessible, this is the moment to specify them properly.
Targeted room coverage
Living spaces, master bedrooms, hero rooms. You don't need ducting throughout — just the key zones treated discreetly. One outdoor unit can run multiple bulkhead heads.
What you need to know before specifying it
Bulkhead systems are a great solution for the right project — but they're not a swap-in option late in a build. The plasterboard work, structural framing, condensate drain and access for service all need to be planned at design stage.
If the trade-offs don't fit your project, we'll guide you to a wall split or full ducted system instead.
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Bulkhead system questions answered
How much of the ceiling does the bulkhead actually drop?
Typically 250–350mm, depending on the indoor unit size and the duct path to the diffuser. We usually run it along a hallway, wardrobe line or kitchen edge — somewhere the dropped section reads as a deliberate architectural feature rather than a compromise. In rooms with high ceilings, the local drop is barely noticeable.
Is a bulkhead system the same as ducted air con?
Not quite. Ducted reverse cycle uses a single large unit in the ceiling cavity with ducts running to multiple ceiling vents throughout the home. A bulkhead system uses smaller indoor units hidden in a localised soffit, with short runs to one or two slot diffusers per unit. Bulkhead is somewhere between a split and full ducted in scale and cost.
Can one outdoor unit run multiple bulkhead heads?
Yes — most installs use a multi-head outdoor unit that can run several indoor bulkhead units from a single compressor. This keeps outdoor equipment to a minimum and lets each room run its own temperature setting. For larger or more zoned homes, we sometimes specify a residential VRV system instead.
Does it heat as well as cool?
Yes — all our bulkhead systems are reverse cycle, meaning they heat in winter and cool in summer using the same equipment. They're an efficient electric heating option, especially when paired with smart controls that pre-warm rooms before you wake up.
How is it serviced if everything's hidden?
We design in a service access panel (typically 600×600mm) in the bulkhead, usually positioned somewhere visually neutral like above a wardrobe door. Filters need cleaning every few months and the unit itself gets a full service annually. The panel is painted to match the ceiling and is almost invisible when closed.
Can it be retrofitted to an existing home?
Sometimes — but it's significantly easier and cheaper to specify during a build or major renovation. Retrofitting means opening ceilings, framing the bulkhead, running refrigerant lines and condensate drains, and re-plastering. If your home is already finished, a wall split or a fully ducted retrofit is often a better path.
How noisy is it compared to a wall split?
About the same — modern indoor units run at 25–35 dB, quieter than background conversation. The bulkhead enclosure can dampen sound slightly, but the dominant noise is the airflow through the diffuser, which is similar across formats. The outdoor unit is the louder component in any system and needs sensible siting.
What brands do you install?
Daikin, Mitsubishi Electric, Fujitsu, Toshiba and Samsung are our most common bulkhead-system brands. We recommend based on the room layout, capacity needed and budget — not based on whichever brand we have stock of. Every brand we install has full Australian warranty cover.
Building or renovating and want discreet AC done right?
Book a free assessment and we'll review the architecture, recommend the right bulkhead layout, and coordinate with your builder on the plasterboard and framing detail.