Ducted (concealed) air conditioning is the ultimate trend in modern homes and hotels. The unit hides in the ceiling void and air travels through ductwork, exiting from elegant linear grilles.
But one central unit + one thermostat = zero autonomy. If you want cooling in the bedroom, the empty living room freezes too. How do we solve this air-duct puzzle?
Converting a central ducted unit into a multi-zone system requires a "surgical" installation inside the ceiling void. It consists of three key components.
At the unit's outlet sits a special metal box (Plenum). From it, separate ducts branch to each room. At the start of each duct, a motorized damper is installed - a metal or plastic disc with an electric motor that opens or blocks airflow.
Each room gets its own independent thermostat (often wireless, touch-type or even touchscreen). Each thermostat controls exclusively its own duct damper - no interaction with other rooms.
A central PCB (like the renowned Airzone systems) collects commands from all thermostats and "orchestrates" the dampers, fan and air conditioning unit in harmony.
The HVAC engineer calculates each duct cross-section so air velocity stays below 3-5 m/s (silent operation). Pressure sensors are placed in each duct and the controller is calibrated accordingly.
Let's say you've set the bedroom to 25°C and the living room to 27°C (summer). What happens step by step?
The bedroom reaches 26°C (setpoint 25°C). Its thermostat sends a "cooling needed" command to the central controller.
The controller opens the bedroom damper. Simultaneously, it sees the living room (27°C ≤ setpoint 27°C) needs nothing - its damper stays hermetically sealed.
The controller sends a digital command to the central AC unit to start (via Gateway). All the chilled air now goes exclusively to the bedroom!
Once the bedroom hits 25°C, its damper closes. If no room is calling, the controller shuts down the AC unit entirely. Zero energy waste in empty spaces.
Here lies the biggest trap in budget or DIY installations. Imagine a unit designed to blow air for 4 rooms simultaneously.
You close 3 dampers (no cooling needed). The entire air volume tries to squeeze through just one duct to the 4th room! Static pressure skyrockets - air blasts out like a hurricane.
Air whistles through the duct and grille. Noise can exceed 55 dB - enough to ruin sleep. In hotels, this means guest complaints and negative reviews.
The AC unit's motor strains dangerously. Elevated static pressure causes overheating, shortened lifespan, or even compressor burnout.
No zoning system should operate with more than 70% of dampers closed simultaneously, unless proper pressure management is installed (see below).
For a damper system to work properly, there must be perfect harmony between controller and AC unit. The controller (e.g. Airzone) has a dedicated Gateway that communicates with the unit's PCB.
When 3 of 4 dampers close, the controller simultaneously tells the Inverter fan to drop to minimum speed. The unit produces only the airflow the 1 open room can handle - absolute silence.
In older or non-Inverter units, a "blind" duct (Bypass) with a weighted damper is installed. When pressure rises dangerously, the damper opens mechanically and dumps excess air back to the return.
The best systems (Airzone, Daikin BRC, Mitsubishi PAC) offer digital communication with the AC unit via Gateway. The controller "sees" outlet temperature, COP and faults, adjusting automatically.
Air zoning with motorized dampers is the "Rolls-Royce" of air conditioning. Elegant aesthetics, total autonomy, zero waste in empty rooms. It does require proper HVAC engineering and certified controllers.
🏠 Motorized Dampers + Gateway + Inverter = Concealed AC with full room-by-room control. Without proper pressure management, whistling and equipment damage are real risks - always insist on a controller with Gateway communication.
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