If you’ve been looking into air conditioning, you’ll have seen split systems, multi-splits, portables and “indoor units”, and it gets confusing fast. Here’s the simple version. A split system has two parts: a slim unit on the wall inside and a compact unit outside, joined by a couple of small pipes. It’s what most people mean by home air conditioning, and it’s what we fit across Bristol and Bath. You can see the units we install on our air conditioning page. Here’s how the different types compare and which one suits what.
How a split system works
The outdoor unit holds the compressor, the noisy bit. The indoor unit holds a fan and a coil. Refrigerant runs between them through two insulated copper pipes.
In cooling mode, the indoor unit pulls heat and moisture out of the room and the refrigerant carries it outside, where the outdoor unit gets rid of it. In heating mode, it runs the other way. It pulls heat from the outside air, even on a cold day, and pumps it into the room.
That’s why a modern split system is really an air-to-air heat pump. It heats and cools.
Because the compressor’s outside, the indoor unit is quiet. That makes a big difference in a bedroom.
What’s an “indoor air conditioner”?
People use the term two ways. Sometimes they mean the indoor half of a split system, the unit on the wall. Sometimes they mean a portable air conditioner, a box on wheels that sits in the room.
They’re very different things, so it’s worth knowing which one you’re looking at.
Portable air conditioners
A portable has everything in one box, including the compressor. Hot air goes out through a hose you hang out of a window.
They’re cheap, need no installation and you can move them from room to room. But they’re noisy, because the compressor is in the room with you. They’re also much less efficient. And with a window open for the hose, warm air comes straight back in.
Fine as a stopgap. Not something we’d recommend if you’re after a proper fix.
Single split systems
One indoor unit, one outdoor unit. This is the most common setup we fit, perfect for a bedroom, a home office, a living room or a loft conversion.
It’s the simplest and cheapest permanent option, and installation is usually done in a day.
Multi-split systems
One outdoor unit running two or more indoor units in different rooms. Each room has its own controls, so you can cool the bedroom without cooling the lounge.
It means fewer boxes on the outside of your house. A multi-split usually takes about two days to install.
Single room or whole house?
Most homes here don’t need whole-house air conditioning. It’s usually one or two rooms that get unbearable: the top-floor bedroom, the loft office, the conservatory.
Starting with the worst room or two makes a lot more sense than trying to cool the whole house. You can always add more later, especially if you go for a multi-split outdoor unit with spare capacity.
Ducted systems, where the air goes through hidden ductwork, are common in new-builds and commercial buildings, but they rarely make sense to retrofit into an existing UK home.
The units we fit
We fit Bosch split systems. The Climate 3200 is a solid, efficient everyday unit with a 5-year manufacturer’s guarantee. The Climate 7000 is the flagship, with better efficiency, quieter running and a 7-year guarantee on parts and labour.
Which one suits you depends on the room, how much you’ll use it and your budget. We’ll recommend one at the survey.
Split systems in Bristol and Bath homes
Bristol’s terraces and Bath’s stone houses often have limited outside wall space, and the pipes have to get from the indoor unit to the outdoor one. We usually aim for the back of the house, where the outdoor unit is out of sight and away from neighbours’ windows.
In flats, there’s often less choice, and you may need the freeholder’s permission. Have a look at is my home suitable for air conditioning if you’re not sure.
Frequently asked questions
Do split systems heat as well as cool?
Yes. The units we fit are reversible heat pumps, so they heat in winter and cool in summer. They’re an efficient way to heat a single room, especially somewhere the central heating struggles to reach, like a conservatory or loft.
What size split system do I need?
It depends on the size of the room, how much sun it gets, the insulation and how many people use it. A small bedroom needs a lot less than a big south-facing lounge. See what size air conditioning unit do I need, and we’ll check it properly at the survey.
Can I fit a split system myself?
No. Connecting the pipework and handling refrigerant has to be done by an F-gas certified engineer, and the electrical connection needs to meet the wiring regulations. We’re REFCOM registered for exactly this kind of work.
Want to know which type suits you?
Ring us on 01275 400 687 or send us a message and we’ll come and have a look, with a free survey.