Air Conditioning Indoor Unit Types Compared

By the AirCon Doctor team · Updated 30 October 2026

Most people picture air conditioning as a white box high on a wall. That is the most common type, but there are several others, and the right choice depends on the room, the ceiling, how much you want to see and how the air needs to move. Many outdoor units work with several indoor styles, so in a multi-split you can mix types from room to room.

This guide explains each type in plain terms. When we survey, we suggest the type that suits the space, not just the one that is quickest to fit.

Wall-mounted

The standard split system. The indoor unit sits high on a wall, usually an external wall or one close to it, and blows air across the room. It is the simplest to install and service, and the widest range of models and sizes is available.

Suits: bedrooms, living rooms, home offices, small offices.
Think about: wall space above head height, the pipe route, and whether you’ll mind seeing it.

See wall-mounted air conditioning.

Floor-standing and console

Floor and console units sit low on the wall, roughly where a radiator would go. Some are designed to be recessed into a wall. Because they discharge warm air low down, many are good at heating, so they suit rooms where the system will be used as a heat pump in winter.

Suits: loft rooms with sloping ceilings, conservatories, rooms with little high wall space, homes where heating is the main use.
Think about: they take up floor-level wall space and need clear airflow in front.

Ceiling suspended

A ceiling suspended unit is fixed flat to the underside of the ceiling and blows air along it. It doesn’t need a ceiling void, which makes it useful in spaces with solid or high ceilings.

Suits: shops, restaurants, open-plan offices, workshops, large rooms without a suspended ceiling.
Think about: it is visible and fairly large, so it suits commercial spaces more than living rooms. It is also straightforward to reach for filter cleaning, which helps in busy premises.

Want it done properly? AirCon Doctor installs, repairs and services air conditioning and heat pumps across London and the South East, from our base in East Grinstead. We’re an F-Gas certified company and NICEIC approved. Get a fixed-price quote.

Ceiling cassette

A cassette sits in the ceiling void with only a square grille visible. It usually blows air in several directions, which gives even coverage in larger rooms. Many come with a built-in condensate pump.

Suits: offices, shops, open-plan living areas, rooms with a suspended ceiling or enough depth to build one.
Think about: you need ceiling depth and access, and the grille is still visible.

See cassette air conditioning.

Ducted

A ducted unit is hidden completely in a ceiling void, loft or bulkhead. Ductwork carries air to discreet grilles, and one unit can serve more than one area. Only the grilles and a controller are visible.

Suits: new builds, major refurbishments, homes where appearance matters most, larger offices.
Think about: it needs space for the unit and ducts, careful design for noise and air balance, and access for filter cleaning.

See ducted air conditioning and our ducted guide.

Quick comparison

Type	Visibility	Needs a ceiling void	Typical use
Wall-mounted	Visible	No	Homes, small offices
Floor / console	Visible, low down	No	Loft rooms, conservatories, heating-led rooms
Ceiling suspended	Visible	No	Shops, restaurants, large rooms
Cassette	Grille only	Yes	Offices, retail, open-plan rooms
Ducted	Grilles only	Yes, or a loft or bulkhead	Whole floors, new builds, premium homes

Mixing types and choosing

With a multi-split, one outdoor unit can run different indoor types, as long as the manufacturer lists them as compatible. A common arrangement is wall units in bedrooms with a cassette or ducted unit in an open-plan kitchen and living area. If looks are the priority but a wall unit is the only practical option, design-led models are an option; see our guide to design air conditioning units.

Our prices start at £1,200–£2,200 + VAT for a single room split. Cassette, ducted and multi-room systems are priced after a survey, because the ceiling, ductwork and pipe route make the difference.

Quick answers

Which indoor unit is the quietest?

It depends on the model and installation more than the type. Ducted systems can be very quiet in the room if the ductwork is designed well. Compare the manufacturer’s published sound levels.

Can I have a cassette without a suspended ceiling?

Only if there is enough depth above the ceiling, or a section is dropped to make space. Otherwise a ceiling suspended or wall unit is usually easier.

Are floor units better for heating?

Because they release warm air low down, they often suit heating well, which is why they’re popular in rooms used mainly in winter.

Can one outdoor unit run different indoor types?

Often, yes, with a multi-split, as long as the manufacturer lists the combination as compatible.

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More advice

This guide is general information, checked against the sources linked on 30 October 2026. It isn’t legal, tax or financial advice. Rules, grants and product ranges change, so check the current position before you rely on it.