Most homes are fitted with a wall-mounted split system: one unit inside, one outside, joined by pipework. It is a straightforward job when it is planned properly. Here is what that planning and the work itself look like.
1. A survey of the room
Good installations start with a visit. We look at the room, where the indoor unit can sit with clear airflow, where the outdoor unit can go, and how the pipes will travel between the two. You get the answer and a quote after the visit, not before it.
2. Getting the size right
Air conditioners are rated in kilowatts. A unit that is too small runs flat out and never quite reaches the temperature you want. One that is too big switches on and off constantly and is less comfortable. Floor area matters, but so do the things people forget: how much glass the room has, which way it faces, whether it is a loft conversion with a sloping ceiling, and what the room is used for.
3. The two units and the route between them
- Indoor unit: mounted high on a wall, with room for air to leave it and return to it.
- Outdoor unit: on a wall bracket or a ground stand, somewhere with airflow and with your neighbours' windows in mind.
- The link: two refrigerant pipes, a control cable and a drain for the water the unit removes from the air. The pipes pass through a neat core-drilled hole and are usually run in trunking.
The drain needs a fall so water leaves by gravity, which is one of the things we check at survey.
4. Power
The unit needs a suitable electrical supply. At survey we look at what is already there and tell you if anything needs doing before the day, so it can be dealt with and written into the quote rather than discovered halfway through.
5. On the day
- The indoor bracket goes up, the hole is core-drilled and the outdoor unit is fixed in position.
- Pipework and cable are run and connected.
- The pipework is pressure-tested and evacuated before any refrigerant is released. Refrigerant is an F-gas, so this part must be done by a qualified technician working for a certified company. More on the F-gas rules.
- The system is run in both cooling and heating mode.
- The installer should show you how to use the controller, including the settings that keep running costs down.
How long the work takes depends on the room, the number of units, the length of the pipe runs and how easy the access is. We confirm timing at the free survey.
Do I need permission?
A domestic wall-mounted unit often falls under permitted development, but it depends on the property. Flats, listed buildings and conservation areas have extra rules, and there are limits on siting and noise. If you rent, or own a leasehold flat, speak to your landlord, freeholder or managing agent first. If we think you should check with the council, we will say so before you order anything.
What to ask any installer
- Is your company F-Gas certified, does the technician hold a personal F-gas qualification, and can I see both?
- What is included in the quote, and what is not?
- Where will the outdoor unit go, and how will the drain run?
- Who services it afterwards?
We are F-Gas certified and we are happy to talk any of this through before you commit to anything.