Ducted · Concealed in the ceiling · Daikin
Daikin slim ducted (R32)
Only 200mm tall, so it fits shallow ceiling voids. Just the grilles show in the room.
- DC fan motor for low energy use
- Flexible duct runs
- Suits homes, small shops and offices
Ducted air conditioning
Ducted air conditioning: heat and cool every room, see almost nothing
Ducted air conditioning hides the indoor unit in a loft or ceiling void and sends air to each room through ducts. All you see is a slim grille and a controller on the wall. Apex designs and fits ducted systems for whole homes, extensions and offices across Kent, south-east London and central London.
How it works
How does ducted air conditioning work?
The indoor unit, sometimes called an air handler, draws air back from the rooms through a return grille, filters it, heats or cools it, then pushes it out through supply ducts to a grille in each room.
Refrigerant pipes link it to an outdoor unit, exactly as with a wall split. A controller on the wall sets the temperature. With zoning, each room gets its own thermostat and a motorised damper that opens and closes its duct.
Ducted units come in slim versions for shallow voids. Some are only 200mm to 250mm tall, which is why they can often fit above a lowered ceiling in a hallway or landing.
Why the plenum matters
The plenum is the box on the unit where air collects before it splits into the ducts. Get it wrong and some rooms get too much air and others too little, and the system gets noisy. Sized and built properly, it spreads the air evenly and lets the unit work efficiently.
We fit Airzone motorised plenums on ducted systems that need room-by-room control. On a house in Darenth we fitted a Panasonic 7kW ducted system with Airzone controls for each room's temperature and airflow, alongside a 3.5kW wall unit.
Is it right for you?
Who ducted air con suits
- Whole homes and open-plan living, served from one or two hidden units.
- Loft conversions, extensions and refurbishments, where we can plan the ducts in.
- Bedrooms upstairs, with a unit in the loft feeding each room through the ceiling.
- Offices, showrooms and restaurants, where air needs to reach a big area evenly.
- Period and design-led homes where nothing should spoil the walls.
Why people choose ducted
- Nothing on the walls: only grilles and a controller.
- Very quiet, with the unit away from the room.
- Even air through large spaces.
- Room-by-room control with Airzone.
What to plan for
- Needs loft or ceiling space for the unit and ducts.
- Best planned during building work, before ceilings are finished.
- Needs an access hatch to reach the unit for servicing.
Planning the layout
Where does the ducted unit go?
- In the loft. The most common spot in a house. The unit sits on a boarded platform near the hatch, with insulated ducts dropping to each bedroom ceiling. Ducts in a cold loft must be well insulated, or they lose heat and can drip with condensation.
- In a ceiling void. Above a suspended ceiling, a bulkhead or a lowered hallway ceiling. Common in offices, flats and ground floors.
- In a cupboard or plant space. Sometimes possible on the same floor, with short duct runs to the rooms around it.
Wherever it goes, the unit needs a drain for the water it makes when cooling, a power supply and a way for an engineer to reach the filter and fan.
Whole house air conditioning
One big unit, or several smaller ones?
There is more than one way to air-condition a whole house with ducted units. These are real setups from our own jobs:
- One 7kW ducted system with Airzone zoning, serving several rooms from one unit.
- Two 2.5kW ducted units on one outdoor unit, each supplying its own bedroom.
- Two 7kW ducted units on a twin split, for a very large kitchen-dining area.
- A 10kW ducted system for a home, with a Wi-Fi controller.
- A 7kW Daikin ducted system with a Madoka controller for a house in Benenden.
A single zoned unit keeps costs and outdoor kit down. Separate units give each area its own system, so one fault does not stop the whole house.
Compare
Ducted air conditioning vs split systems
Both use the same outdoor units and both heat and cool. The difference is where the indoor unit lives and how the air reaches the room.
Swipe sideways to see the whole table →
| Point | Ducted | Wall splits (single or multi) |
|---|---|---|
| What you see | Grilles and one controller | A unit on the wall in each room |
| Noise in the room | Very low | Low |
| Control per room | Needs zoning (Airzone) | Built in: each unit has its own remote |
| Building work | Ducts, grilles, ceiling openings | One small hole per room |
| Best time to fit | During building work | Any time |
| Cost | Higher | Lower |
If you only need one or two rooms, wall mounted air conditioning is usually quicker and cheaper. For one large open room with a ceiling void, a ceiling cassette is another option.
Cost
How much does ducted air conditioning cost?
Published UK guides put ducted systems for several rooms at roughly £5,000 to £15,000 or more (Selectra, Ideal Home and MyBuilder, 2026). That is a wide range, because every ducted job is designed for the building. The main things that move it:
- The number of rooms and the total kW needed.
- One zoned unit or several separate ones.
- Duct runs, grilles and any bulkheads or ceiling work.
- Zoning: the number of zones and the type of thermostats.
- Access to the loft or void, and where the outdoor unit goes.
We survey, design the layout and give you a fixed written quote. Our running costs guide explains what it costs to run.
Commercial
Ducted systems for businesses
Ducted units suit offices and showrooms because the air reaches a big floor evenly and the ceiling stays clean. We have fitted 16 ducted indoor units across a commercial floor in the City of London, and seven ducted units heating and cooling a developer's marketing suites. We also repair older ducted units, including a fan motor replacement on a Daikin ducted unit.
More on commercial air conditioning, including maintenance and TM44 records.
WhatsApp a floor plan
A floor plan or a few photos of the loft help us give a first idea.
Ranges we fit
Ducted units we fit
Ranges we fit include these. Makers update their models often, so we recommend the current one that suits your room and budget at the survey.
Ducted · Concealed in the ceiling · Mitsubishi Electric
Mitsubishi Electric PEAD-M
A ceiling-concealed unit only 250mm tall, with a drain pump built in.
- 250mm high
- Wide range of duct pressures
- Drain pump as standard
Ducted · Concealed in the ceiling · Mitsubishi Electric
Mitsubishi Electric SEZ-M
A low, light ducted unit designed for offices, restaurants and shops.
- Low noise
- 7-day programmable timer
- Group control for up to 16 units
Also in the range
- Panasonic ducted (Panasonic) Concealed in the ceiling. Hidden in the ceiling or loft, and pairs with Airzone dampers for room-by-room control.
Real Apex jobs
Ducted systems we have fitted
Real job photo 
Real job photo 
Real job photo 
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Other types of system
Wall-mounted systems
The most popular choice for bedrooms and living rooms.
Find out moreFloor-mounted systems
Low on the wall, ideal for lofts and replacing radiators.
Find out moreCeiling cassettes
Even airflow for offices, shops and open-plan rooms.
Find out moreAirzone zoning
Room-by-room temperature control for ducted systems.
Find out moreBrands we fit
Daikin, Mitsubishi Electric and Panasonic.
Find out moreQuestions
Ducted air conditioning questions
Can ducted air conditioning be retrofitted?
Yes, if there is room in the loft or a ceiling void for the unit and the ducts. Upstairs rooms are the easiest, because the ducts drop through the ceiling from the loft. Downstairs rooms usually need a bulkhead or a lowered ceiling. It is simplest during a loft conversion, extension or refurbishment, when we can work with your builder.
Can each room be a different temperature?
Yes, with zoning. On a standard ducted system, every room gets air at the same set temperature. Add Airzone zoning, with a motorised damper and a thermostat for each room, and you can set each room on its own, or switch rooms off when nobody is using them.
Is ducted air conditioning noisy?
It is one of the quietest options, because the unit sits away from the room in the loft or ceiling void. Only air moves through the grilles. A well-built plenum and ducts sized for the airflow keep the air speed, and the noise, down. Undersized ducts are the usual cause of a whistling ducted system.
Does ducted air conditioning heat as well as cool?
Yes. The ducted systems we fit are heat pumps, so the same unit warms the house in winter and cools it in summer. Warm air comes from ceiling grilles, so in high rooms we angle the grilles and set the fan to push heat down to where you sit.
Does ducted cost more than wall units?
Usually yes, because of the ductwork, grilles and building work. In return you get nothing on the walls and several rooms served from one hidden unit. Our cost guide explains what drives the price, and we give you a fixed written quote after the survey.
Does ducted air conditioning need servicing?
Yes, once a year like any system. We clean or replace the filter at the return grille, check the drain and pump, clean the coil and fan, and test the controls and zones. A clogged filter starves every room of air at once, so in dusty homes you may need to rinse it between services.
Get a quote for a ducted system
Talk to Olly directly. He quotes and fits the jobs himself.
Quickest way to a price: send on WhatsApp
- A photo of the room and the outside wall
- Your town and what you need
- For a repair, the unit's label and any error code
Free survey and a fixed written quote for new systems. No obligation.