Ceiling Cassette Air Conditioning

A ceiling cassette is an indoor air conditioning unit that sits inside the ceiling, with only a flat panel showing. It draws air in through the centre of the panel and blows it out through louvres around the edges, usually in four directions. Cassettes are common in offices, shops and restaurants, and they suit some homes too, especially open-plan kitchen-diners and extensions.

How a Cassette Works

A cassette is part of a split system. It takes the place of a wall unit, and an outdoor unit does the work outside, connected by refrigerant pipes, a cable and a drain. The pipes run through the ceiling void, so nothing shows in the room apart from the panel and a controller. Cassettes heat as well as cool.

Cassettes usually have a built-in pump that lifts the condensate water up to a drain, which gives more freedom over where the drain pipe runs.

Types of Cassette

• Compact four-way cassettes are made to fit a standard 600 × 600 mm suspended ceiling tile, so they drop into an office ceiling grid.

• Larger four-way cassettes have bigger panels and higher outputs for large open spaces.

• One-way and two-way cassettes blow air in one or two directions. They suit narrow rooms, corridors and positions along a wall.

Where Cassettes Work Well

• Offices, shops, salons and restaurants with a suspended ceiling. See office air conditioning.

• Open-plan living areas and kitchen-diners, where a cassette near the middle of the ceiling spreads air more evenly than a unit on one wall.

• Extensions and new builds, where the cassette can go in before the ceiling is finished.

• Rooms with little free wall space, such as rooms with lots of windows or tall units.

What Space Does a Cassette Need?

The body of the unit sits above the ceiling, so you need a ceiling void deep enough to take it. Many compact cassettes need around 250 to 300 mm, and slimmer one-way models need less. In a home, the joists, the direction they run and anything else in the ceiling, such as lights, pipes and cables, all affect where a cassette can go. We check all of this at the survey.

The filter sits behind the panel, so cleaning and servicing are done from inside the room.

Advantages

• Discreet, with only a flat panel showing, flush with the ceiling.

• Even airflow in several directions, which suits larger and open-plan rooms.

• Frees up wall and floor space.

• Individual louvre control on many models lets you direct air away from desks or seating.

Disadvantages

• More installation work than a wall unit, especially in a plastered ceiling, where an opening has to be cut.

• It needs a deep enough ceiling void.

• It usually costs more than a wall unit of the same output.

• The filter has to be cleaned from below, so you need a step ladder. See how to clean your air conditioner.

Cassette, Wall Unit or Ducted?

If there is a suitable ceiling void and you want the unit out of the way, a cassette is a good middle ground. It is more discreet than a wall unit and needs less building work than a fully ducted system. If you want nothing on show except grilles, a ducted system goes further. If budget comes first, a wall unit is the simplest choice.

What Does It Cost?

As a guide, one room typically starts from around £2,500 and multi-room systems usually range from £5,000 to £10,000+. A cassette usually costs more than a wall unit, and the final price depends on the ceiling, the pipe route, the outdoor unit position and the electrical work. We give you a clear written quote after a free survey.

Frequently Asked Questions

Can a ceiling cassette go in a plasterboard ceiling?

Often, yes, but the joists decide where. A compact four-way cassette is wider than the gap between the joists in many homes. The joist layout affects where it can go, and whether a slimmer one-way model would fit better. We check this at the survey.

Are ceiling cassettes noisy?

The noisiest parts, the compressor and the main fan, are in the outdoor unit. Indoors you hear the fan, which is quiet on its lower settings.

Can one cassette cool a whole open-plan floor?

It depends on the size of the space and how much heat it gains. Large open spaces often need two or more cassettes so the temperature is even.

Do I need planning permission?

Usually not for a house in England, as long as the outdoor unit meets the permitted development limits. Flats, listed buildings and some conservation areas follow different rules. See our planning permission guide.

Call 01772 288651 or use the form below to book a free survey. We will measure the room, recommend the right system and give you a clear written quote.

Last updated: November 2026.