Split & Wall-Mounted Air Conditioners

Often not for a single outdoor unit on a typical house, as it can fall under permitted development in England. However, conditions apply: the unit usually can't face or front a highway, must be sited sensibly away from boundaries, and permitted development is removed in conservation areas and for listed buildings. Always check with your local planning authority before installing, as Scotland, Wales and Northern Ireland have their own rules.

A conventional split system cannot legally be self-installed, because handling the R32 refrigerant and commissioning the unit requires an F-Gas certified engineer. The exception is an easy-fit, pre-charged split, where the refrigerant is sealed in the lines so a homeowner can connect it without handling gas. Even then, you must follow the instructions precisely, and the electrical connection should be done by a qualified electrician.

For a standard single-split system, professional supply-and-fit typically runs from a few hundred pounds up to around £1,500+, depending on the pipe run, wall access and the installer. Multi-split systems cost more as there's more pipework and labour. An easy-fit pre-charged unit avoids most of that installation cost, though you'll still want an electrician for the power supply.

Yes. Pre-charged easy-fit splits are sold for homeowner self-installation in the UK because the refrigerant is factory-sealed in the lines, so no F-Gas handling takes place during fitting. They're a popular workaround for people who want a wall-mounted split without paying for a certified installer. Just follow the manufacturer's instructions carefully and use a qualified electrician for the electrical connection.

A single-split system pairs one indoor wall unit with one outdoor condenser, ideal for cooling a single room such as a bedroom or office. A multi-split connects several indoor units to one outdoor condenser, letting you cool multiple rooms from a single outdoor box, which is tidier and saves wall space outside. Multi-split costs more upfront and to install, but is efficient for whole-home or multi-room cooling.

Standard split systems do, because connecting, vacuuming and charging the refrigerant lines is regulated work that legally requires an F-Gas certified engineer. This protects against refrigerant leaks and ensures the system is commissioned correctly for efficiency and warranty. The only common exception is a pre-charged easy-fit unit, which is designed so no gas handling occurs during a homeowner install.

Yes, most modern split air conditioners are reversible heat pumps, meaning they run the refrigeration cycle in reverse to provide warmth in winter as well as cooling in summer. This makes them a year-round climate solution and often cheaper to run for heating than electric heaters, as a heat pump moves heat rather than generating it directly. Check the product spec for a heat-pump or reversible-cycle label.

Split systems are among the quietest air conditioners available, because the noisy compressor sits outside in the condenser unit. The indoor wall unit typically runs at a low hum, with many inverter models offering a quiet or sleep mode in the low-to-mid 20s dB(A) on their lowest fan setting. Check the indoor unit's quoted dB(A) figure on each product page and use our noise filter to find the quietest options for bedrooms.