Air conditioning installation in Croydon

What goes into a split system installation?

Two boxes and the link between them. The indoor unit sits high on the wall of the room. The outdoor unit, which holds the compressor and a fan, stands on a bracket or a plinth outside. Running between them are a pair of insulated refrigerant pipes, a control cable and a small drain for the water the indoor unit pulls out of the air. Where the room backs onto the garden, one cored hole carries the lot. Where it does not, the route is the real job: along a side return, down a rear wall in trunking, or through a ceiling void in a flat.

What happens at the survey?

• We measure the room, note the ceiling height and see which way the glass faces. A north-facing box room and a south-facing loft with a Velux are different jobs.
• We ask who owns the outside wall. In a flat it is usually the freeholder, and in a rented house it is the landlord.
• We find a spot for the outdoor unit and work out the sound it would make at the nearest neighbouring window.
• We check the condensate can drain by gravity, or plan a small pump if it cannot.
• We look at the consumer unit and the route for a new circuit.

The written price follows. If the building makes the job impossible, or not worth the money, that is the moment you find out, not after a deposit.

Why do the electrics appear as their own line?

Because they are regulated separately. In England, a new circuit in a home counts as notifiable work under Part P, so it has to be done by an electrician registered with a competent person scheme, or signed off afterwards by a registered third party. The IET lists BESCA, Blue Flame, NAPIT, OFTEC and Certsure (NICEIC and ELECSA) as the approved schemes. Checkatrade's national figure for a fused spur indoors and a weatherproof switch outside is £400 to £700. Keep the certificate: a conveyancer will ask for it when you sell. Sources: IET; Checkatrade cost guide.

How is the system commissioned?

Once the pipes are joined, the circuit is pressure tested with nitrogen to prove it holds, then evacuated with a vacuum pump to pull out air and moisture. Only then is the refrigerant released into the pipework, and by law that step belongs to someone with an F-gas qualification. Modern refrigerants such as R32 are mildly flammable, so a very small room is checked against BS EN 378-1 before the unit is chosen. We then run the system in cooling and heating, measure the air temperatures, and show you the remote. Sources: GOV.UK; Energy Saving Trust.

What moves the price up or down in Croydon?

Capacity first, then the route, then access. A ground-floor room with the outdoor unit directly behind it is the cheapest shape of job. A fourth-floor flat with a long run to a plant area on the roof, or a terrace where the only outdoor position is at the far end of the garden, costs more in pipe, labour and sometimes a tower. As a national starting point, Checkatrade gives £750 for a 12,000 BTU wall unit and £1,150 to fit it, which comes to about £1,900 before the electrics. Our cost guide works through the rest.