If you’ve been googling types of aircon and feeling more confused the longer you scroll, you’re not alone. Split systems, cassettes, multi-splits, VRF, heat pumps… it all sounds a bit technical when all you really want is a comfortable temperature and a sensible running cost.

As a quick intro, Air Conditioning Direct has been supplying and installing air conditioning across London and the South East for over 25 years, working on everything from studio flats to large offices and commercial kitchens. That day-to-day experience is what this guide is based on – not just theory.

Below, we’ll walk through the main types of aircon used in UK homes and businesses, what each one is good at, and the things to watch out for.

1. Before you choose: what actually matters?

Before we get into the different air conditioning units, it helps to think about:

• Your space – size of rooms, ceiling height, layout, number of people
  
• Use – home vs office, occasional use vs all-day, all-year comfort
  
• Electrics and building limits – especially in flats or listed properties
  
• Running costs and energy efficiency
  
• Noise levels – crucial for bedrooms, studies and meeting rooms
  
• Whether you own or rent – affects whether permanent installation is possible
  

When we visit customers at Air Conditioning Direct, we usually start with a quick site survey and talk through these points in plain English. The “best” system on paper isn’t always the right one for how you actually live or work.

2. Wall-mounted split systems

If you picture a typical aircon unit on the wall of a bedroom or office, it’s probably a wall-mounted split system.

What it is:

• One indoor unit on the wall
  
• One outdoor condenser unit usually on a wall, balcony or flat roof
  

Best for:

• Bedrooms, lounges and home offices
  
• Small to medium commercial rooms
  
• Retrofitting in existing properties
  

Pros:

• Generally the most cost-effective, all-round option
  
• Efficient cooling and heating (many are heat pumps)
  
• Quiet operation, ideal for sleeping areas
  
• Good control over temperature in individual rooms
  

Cons:

• You need somewhere suitable for the outdoor unit
  
• You’ll see the indoor unit on the wall (though modern ones are quite sleek)
  

For many UK homes, a simple wall-mounted split system is the “sweet spot” between performance, price and neatness, which is why we install so many of them.

3. Multi-split systems

Take the idea of a single split system and scale it up and you get a multi-split air conditioning system.

What it is:

• Several indoor units (often wall-mounted or floor-mounted)
  
• Connected to one outdoor unit
  

Best for:

• Homes where you want multiple rooms cooled or heated
  
• Flats where there’s only space for one outdoor unit
  
• Small offices or shops
  

Pros:

• Only one outdoor unit, so the exterior of your property looks tidier
  
• Independent control of each room
  
• Often more efficient than running lots of separate portable units
  

Cons:

• Pipework design needs more planning
  
• If the outdoor unit fails, several rooms are affected
  
• Installation cost is higher than a single split (though still sensible long-term)
  

For London properties with limited outdoor space, a multi-split system can be a very neat solution.

4. Ducted / central air conditioning

If you want a completely hidden system, ducted aircon is usually the way to go.

What it is:

• Indoor unit concealed in a loft space, cupboard or suspended ceiling
  
• Air distributed via ducts to grills or diffusers in ceilings or walls
  

Best for:

• New builds or major refurbishments
  
• Larger homes where aesthetics are a priority
  
• Offices, shops and other commercial spaces
  

Pros:

• Very discreet – all you see are grilles or vents
  
• Can serve multiple rooms from one central system
  
• Even air distribution, which feels very comfortable
  

Cons:

• More invasive installation, often needing ceiling voids or loft space
  
• Higher upfront costs than a single split wall unit
  
• Design is crucial – poor ductwork equals poor performance
  

At Air Conditioning Direct we tend to recommend ducted systems when a client is already doing building work or has plenty of ceiling void space to play with.

5. Ceiling cassette units

You’ll see ceiling cassette air conditioners in many shops, restaurants and offices.

What it is:

• Indoor unit recessed into the ceiling grid
  
• Air is blown out on two, three or four sides
  

Best for:

• Open-plan offices
  
• Retail spaces and salons
  
• Areas with suspended ceilings
  

Pros:

• Great coverage in open spaces
  
• Keeps the walls free for shelving or décor
  
• Good option when wall space is limited
  

Cons:

• Needs a suspended ceiling to hide the bulk of the unit
  
• Installation can be more involved than a simple wall unit
  

If you’ve got a high street shop, café or open-plan workspace and you’re exploring different types of aircon, ceiling cassettes are almost always on the shortlist.

6. Floor-mounted and low-wall units

Think of these a bit like a slimline radiator that also cools.

What it is:

• Indoor unit installed low down on the wall or on the floor
  
• Connected to an outdoor unit like any other split system
  

Best for:

• Loft conversions or rooms with sloping ceilings
  
• Spaces with very limited high wall space
  
• Replacing old storage heaters in some cases
  

Pros:

• Good option when a wall-mounted unit is tricky
  
• Airflow can feel more natural at seated height
  
• Often easier to service if access at height is an issue
  

Cons:

• Uses up floor or low wall space
  
• Not quite as popular in the UK, so choice can be slightly narrower
  

We often suggest floor-mounted units in quirky London properties where roof lines and beams make traditional wall units awkward.

7. Portable air conditioners

If you rent or can’t install anything permanent, portable aircon units have their place.

What it is:

• Stand-alone unit on wheels
  
• Usually vents hot air out of a window via a flexible hose
  

Best for:

• Renters who can’t alter the property
  
• Short-term or occasional use
  
• Spot-cooling a room during heatwaves
  

Pros:

• No permanent installation required
  
• You can move them between rooms
  
• Lower upfront cost
  

Cons:

• Noisier than fixed systems
  
• Less energy efficient
  
• You need to manage the exhaust hose and often a window kit
  
• Can struggle in larger or south-facing rooms
  

If you own your home or commercial space and want reliable, year-round comfort, we’ll almost always steer you towards a fixed system rather than relying solely on portable units.

8. Heat pumps and all-year climate control

A lot of modern air conditioning systems are actually air-to-air heat pumps. That means they:

• Cool in summer by removing heat from the indoor air
  
• Heat in winter by extracting warmth from the outside air, even when it feels chilly
  

For many of our customers, this replaces or reduces the need for traditional electric heating and can be more efficient, especially with well-insulated properties.

If you’re thinking long-term and want both heating and cooling in one system, asking about heat pump-based aircon is a smart move.

9. Matching the type of aircon to real-world scenarios

To make this more concrete, here are a few common setups we see at Air Conditioning Direct:

• One-bed flat in London:
  Often a single wall-mounted split system in the lounge, sometimes a second in the bedroom, or a small multi-split.
  
• Three-bed semi-detached house:
  Wall-mounted units in main bedrooms and lounge, often on a multi-split system, or a small ducted system if there’s a loft and the client wants everything hidden.
  
• Small office or salon:
  One or two wall units or a ceiling cassette, depending on layout and ceiling type.
  
• Restaurant / open-plan office:
  Usually a mix of ceiling cassettes or ducted aircon with proper zoning and controls.
  

Every property is different, which is why a site visit and proper design matters. Two spaces of the same size can need different types of aircon depending on insulation, glazing, equipment, people and usage.

10. Why work with Air Conditioning Direct?

Choosing between all these types of aircon is much easier when you’ve got someone experienced in your corner.

At Air Conditioning Direct:

• We’ve got over 25 years’ experience in residential and commercial air conditioning across London and the surrounding areas
  
• We design, supply, install and maintain systems from leading manufacturers
  
• We offer up to a 7-year guarantee on selected equipment when we install and maintain it
  
• Our engineers are fully qualified and used to working in homes, offices, shops and more
  

If you’re weighing up your options and want straightforward advice, you can explore more on our website at ac-direct.co.uk or get in touch for a free, no-obligation chat about your space.

Final thought

There’s no single “best” system. The right choice comes down to your property, how you use it and what matters most to you – be that aesthetics, energy efficiency, budget or all-year comfort.

Hopefully this guide has demystified the main types of aircon and given you a clearer idea of where to start. If you’d like tailored recommendations for your home or business, Air Conditioning Direct is here to help, contact us today by calling 020 8989 8989 or completing our online contact form.