Air conditioning costs: fitting, wiring and the bills that follow

What do national figures say one split costs to fit?

Roughly £1,900 once the unit (12,000 BTU) and its fitting are added together (our addition of Checkatrade's numbers), with wiring on top. Checkatrade's cost table, last revised in May 2026, prices a wall-mounted split on a masonry wall as follows:

The same page also quotes looser bands for the 12,000 BTU size, £620 to £890 for the unit and £960 to £1,380 for labour, so read any single total as a midpoint. The electrics are extra: Checkatrade's allowance is £400 to £700, covering an isolating switch by the outdoor unit and a fused spur inside. Part P makes any new circuit in a home notifiable, so either a scheme-registered electrician self-certifies it or a registered third party signs it off. Sources: Checkatrade; IET.

How does that compare with the Energy Saving Trust's figures?

It lands in the same place. The Energy Saving Trust's advice on air-to-air heat pumps, updated on 20 October 2026, gives £1,900 to heat a single room and £3,700 for a three-bedroom semi-detached house, and warns that extras such as redecorating can add to those. Its figures are framed around winter heating, but the equipment is the same reversible split, and the Trust notes it can also cool in warm weather. The air-to-air heat pump page covers that use. Source: Energy Saving Trust.

What can add to the bill in Ilford?

Mostly the building's ownership and position rather than the equipment. Allow for these where they apply:

Several of these are common here. In Ilford Town ward 55% of households live in flats and 56% rent privately, against 30.45% private renting across Redbridge, and the borough has 16 conservation areas. Sources: LEASE; Planning Portal; Area Insights, Ilford Town ward; Area Insights, Redbridge; Redbridge Council.

What does it cost to run once it is in?

Pence an hour rather than pounds. At 26.32p per kWh, the capped rate for the last quarter of 2026, a modern 2.5 kW split working flat out at its rated test point uses about 13p to 17p of electricity an hour on our sums, and the seasonal ratings on the same data sheets point to less across a whole summer. The running costs guide sets out the working, a season's cooling and how winter heating compares with gas. Sources: Ofgem; Mitsubishi Electric; Fujitsu.

What does it cost to keep a system going?

Chiefly a yearly service; Checkatrade's national figure for a one-off visit is £70 to £120 a unit. A legal leak check is a separate question, and a single modern room unit usually falls outside it. The legal duty begins at a charge equivalent to 5 tonnes of CO2, which GOV.UK illustrates with 2.4 kg of R410A; a current 2.5 kW split on R32 holds about 0.8 kg, which Mitsubishi's data sheet puts at 0.540 tonnes. Separately, where the air conditioning one person controls in a single building totals more than 12 kW, TM44 inspections are needed, no more than five years apart. See servicing for what a visit covers. Sources: Checkatrade; GOV.UK on leak checks; Mitsubishi Electric; GOV.UK on TM44.

How should you compare two quotes?

Line by line, because a bare total hides whatever has been left out. A written quote worth comparing states:

• the cooling and heating output in kW, and the make and model;
• whether the electrics are included, and who issues the Part P certificate;
• how many metres of pipe are allowed for, and the charge for more;
• any access equipment for an outdoor unit above ground level;
• the company F-gas certificate the work is done under (our F-gas register guide explains checking one);
• who carries out the MCS 020a noise calculation and handles any application or consent;
• the warranty, and what servicing it depends on.

Hold every quote to that list, ours included. For how we survey and fit, read about our Ilford air conditioning service.