How expensive is air conditioning to install at home?

For a fixed, properly installed system, UK air conditioning in 2026 costs £1,500–£3,000 for a single-room split system — one indoor wall unit plus an outdoor condenser, and the most popular choice for a bedroom, home office or lounge. Cooling more rooms from one outdoor unit, a two-room multi-split runs £2,800–£4,500 and a three-to-four-room multi-split £3,500–£7,000. Whole-home ducted systems, with the kit hidden in ceilings or walls, are a bigger project at £6,000–£15,000.

Portable units are the cheap alternative at £200–£500 with no installation, but they are noisier and far less efficient than a fixed split system.

Two things to know before getting quotes. First, all fixed systems must be installed by an F-Gas registered engineer — it is a legal requirement because of the refrigerant involved, so always check registration. Second, location matters: London and the South East typically add 20–30% to installation prices.

Beyond that, price moves with capacity (a bigger room needs a bigger unit), how far the outdoor unit sits from the indoor one, and whether any electrical work is needed for a dedicated supply.

What about running costs and upkeep? For cooling, a modern A-rated split system is cheap to run — often only a few pounds a week even in a hot spell, and less again if the unit is correctly sized and you use the timer rather than leaving it on all day. The same kit doubles as an efficient heater in spring and autumn, which many owners value as much as the cooling. Budget for one cost on top: fixed systems should be serviced roughly once a year (around £80–£150) to keep the manufacturer warranty valid and the sealed refrigerant circuit healthy.

Our air conditioning cost guide breaks costs down by room, brand and running cost per summer. Ready for numbers for your own home? Compare three free quotes from vetted installers.