Discover how Expella’s new Shadowline Diffuser AC range integrates with ducted air conditioning to clear the visual graffiti of conventional grilles and vents.
For Alexander &CO Principal Architect Jeremy Bull, conventional air conditioning and ventilation grilles are one example of infrastructure becoming a visual interruption.
“In design, we're trying to avoid exposing the working components of the infrastructure,” says Jeremy. “If there's an air conditioning grille on the ceiling and it's a large plastic grille, what we're really trying to do is remove this graffiti.”
Expella’s popular Shadowline Diffuser ventilation range now extends into air conditioning grilles. With their new Shadowline Diffuser AC collection, and their Shadowline Diffuser ventilation collection, the systems still perform, but visually, it can become almost impossible to distinguish the grilles from the architecture around it.
For Jeremy, that is the point.
“I can see how this is going to be a total game changer,” he says. “It's incredible to remove all of the graffiti you usually have to add to your ceiling or to your bulkheads to manage air conditioning. Now it has become invisible.”
Expella's Shadowline Diffuser Pro creates a near invisible exhaust grille in these bathrooms at Nomad House (left) and Pacific House (right) by Alexander &CO.
Making air conditioning disappear
Air conditioning is still essential to comfort, but its visual expression now doesn't need to be.
Conventional grilles can add visual noise to ceilings and walls, particularly in highly resolved interiors where lighting, joinery, and materials have been carefully coordinated.
The Shadowline Diffuser AC Pro can be positioned at the wall-to-ceiling junction to create a near-invisible opening, or integrated within the ceiling to create a discreet slot. For spaces where a circular expression is more appropriate, the Shadowline Diffuser AC Round sits flush with the ceiling.
Jeremy has specified Expella products for more than a decade, and says Expella's approach to discreet infrastructure has consistently delivered.
“We get a more coordinated design. It feels purpose-built, and you're not seeing all the plastic accoutrements that come along with your operating infrastructure hanging out of your ceiling or hanging off your walls.”
A natural fit for Ember
At Ember, a rural retreat in Mudgee, the Expella range suited the project’s minimalist brief. Designed by architects Derek Scholes, Associate Principal at Woods Bagot, and Alyssa Murasaki Saltzgaber, a Senior Associate at Henning Larsen, for their own family and friends, the restrained palette and carefully framed connection to the landscape made unobtrusive comfort paramount.
Purchased in 2022, Ember is sited beside an existing hay shed, with an established tree helping anchor the new building within the paddock. Externally, the building is wrapped in dark Vacoa, a thermally modified timber cladding that gives the house a deep, almost charred appearance.
On entering, a small alcove for removing shoes and jackets reflects Alyssa’s Japanese background and the ritual of leaving the outside world behind. Concrete floors, Blackbutt, grooved wall linings and dark insertions create a warm, restrained palette.
The result is an interior where the architecture is intended to read as a calm, continuous whole. This made the mechanical services an important part of the design conversation.
The ventilation solution was selected with this sense of visual calm in mind. "Internally, we wanted to avoid unnecessary interruption, and Expella’s Shadowline Diffuser air conditioning and ventilation range provided a discreet way of achieving the required ventilation without compromising the simplicity we sought,” says Derek.
Ember is wrapped in dark Vacoa, a thermally modified timber cladding.
The Shadowline Diffuser AC Round sit discreetly on the bedroom ceilings at Ember.
The materials are carefully selected at Ember, views are deliberately framed and light is controlled.
Comfort without the visual noise
The approach to comfort at Ember extends beyond mechanical air conditioning.
The house incorporates solar power, tank water and onsite wastewater treatment, alongside natural ventilation, heavy insulation, double glazing and other passive strategies designed to improve thermal performance.
The philosophy is simple: use the building itself to create comfort wherever possible, and introduce technology where it genuinely improves the experience.
The Shadowline Diffuser range of grilles and Expella's inline fans fit into this philosophy by providing essential climate control without adding another visual layer to the interior.
The architecture is restrained. The materials are carefully selected, views are deliberately framed and light is controlled. And the infrastructure required to make the home comfortable is hidden.
Concrete floors, Blackbutt, grooved wall linings and dark insertions create a warm, restrained palette.
Shadowline Diffuser Pro is installed discreetly in the bathroom skylight at Ember.
Designed to be forgotten
For Jeremy, good infrastructure is ultimately measured by how little attention it demands once it is installed.
“The objective isn't necessarily to remove everything from view. It is to make sure that the elements required to make a building operate don't unnecessarily compete with the elements which give it character,” he says. “When I specify Expella's products. We don't talk about it. It goes into the specification, and it never comes up as a problem.”
This reliability is particularly important with concealed systems, where coordination between the diffuser, plasterboard and finishing trades needs to happen early.
For a practice working predominantly on high-end architectural projects, Jeremy sees the additional coordination as worthwhile, because when everything works seamlessly, and the infrastructure disappears, the architecture can be seen in its truest expression.
“If there's an air conditioning grille on the ceiling and it's a large plastic grille, what we're really trying to do is remove this graffiti.” - Alexander &CO Principal Architect Jeremy Bull.
