Air Conditioning and Building Regulations in England

By the AirCon Doctor team · Updated 30 October 2026

Building regulations are about how work is done, not whether you’re allowed to do it. Planning is a separate question, covered in our planning permission guide. For a typical home installation, the parts that matter are the electrical work, the energy efficiency of the system and, if ventilation is involved, the rules on ventilation.

This guide covers England, using the Approved Documents on GOV.UK and the Planning Portal. Wales, Scotland and Northern Ireland have their own systems. It’s general information, not legal advice.

Part P: the electrical work

Part P covers electrical safety in homes. The Planning Portal lists these as notifiable:

installing a new consumer unit or fuse box;
installing a complete new circuit;
altering an existing circuit in a special location, which in England means the space around a bath or shower.

Most air conditioning installations need a dedicated circuit, so the electrics usually fall into the notifiable category. Notifiable work must be inspected and certified by a building control body (or, in England, a registered third-party certifier), with the notice given before work starts, unless the installer is a registered competent person. A registered competent person can self-certify that the work complies.

How NICEIC registration helps

AirCon Doctor is NICEIC approved for electrical work. That means we can self-certify the new circuit as complying with the building regulations, without you having to make a separate building control application. You should receive the electrical installation certificate for the work, and the registration scheme deals with the notification.

Keep the certificates with your house documents. A buyer’s solicitor may ask for them when you sell. Our Part P guide explains more, including what to do if someone else wires the circuit.

Part L: energy efficiency and controls

Part L, conservation of fuel and power, covers fixed building services. Comfort cooling is one of them. Approved Document L sets minimum efficiency values for fixed building services in new and existing homes, and asks that they have effective controls, are commissioned by testing and adjusting as necessary, and come with information on how to operate and maintain them.

In practice, for a fixed split system from a leading brand, that means choosing a unit with suitable efficiency, setting up the controls properly, commissioning it and handing over the manual and settings. Part L carries more weight in new homes, extensions and commercial fit-outs, where the design is assessed as a whole. Buildings other than homes are covered by a separate volume of Approved Document L.

Part F: ventilation

Part F covers ventilation. A standard split system recirculates and cools the air already in the room; it doesn’t bring in fresh air, so it doesn’t replace the ventilation a room needs. Part F becomes relevant when ventilation itself is being installed or changed, for example with mechanical ventilation with heat recovery (MVHR). If you’re planning both, see our ventilation and MVHR page.

Want it done properly? AirCon Doctor installs, repairs and services air conditioning and heat pumps across London and the South East, from our base in East Grinstead. We’re an F-Gas certified company and NICEIC approved. Get a fixed-price quote.

Other parts that can apply

Structure. A large outdoor unit on a roof or a heavy bracket on a weak wall needs a check that the structure can carry it.
Fire. Holes for pipework through fire-resisting walls or floors, common in flats and commercial buildings, need sealing to restore the fire resistance.
New builds and extensions. Where air conditioning is part of a larger project with its own building control application, it’s included in that application.

If a project needs any of these, we’ll say so on the survey.

F-Gas records: not building regulations, still required

The refrigerant side of the job is covered by F-Gas law rather than building regulations. Companies installing or servicing the equipment must be certified by an approved body, and engineers need their own qualifications. For systems holding 5 tonnes CO2e or more, the operator and service company must keep records of the gas, leak checks and the companies that worked on it, for 5 years.

Many small domestic splits hold less refrigerant than that threshold, but we record the refrigerant work on every installation as part of commissioning and handover.

Condensate: where the water goes

In cooling mode, the indoor unit takes water out of the air. That condensate has to go somewhere safe: usually by gravity to an outside drain or gully, or into the internal waste pipework through a suitable trap so smells can’t come back. Where gravity won’t work, a small condensate pump lifts it.

Water left to drip onto a path, a neighbour’s wall or a flat roof can cause slips, stains and damp. In heating mode the outdoor unit also produces water as it defrosts, so its position needs thought too. Our condensate pump guide and leak troubleshooting guide go further.

Commercial buildings and larger systems

For businesses, larger systems bring extra duties. Air conditioning with an effective rated output over 12 kW needs regular energy inspections under the Energy Performance of Buildings Regulations, carried out by an accredited energy assessor. That’s a TM44 inspection, explained in our TM44 guide. We prepare systems for inspection and fix what it finds. F-Gas leak checks also apply to larger systems; see our F-Gas guide for businesses.

What you should receive at handover

the electrical installation certificate for the new circuit;
the F-Gas record of the refrigerant work;
the commissioning record;
the manufacturer’s manual and warranty details;
an explanation of the controls and filter cleaning.

We provide all of these at the end of every installation. Get in touch if you’d like to talk a project through.

Quick answers

Does air conditioning need building regulations approval?

Usually the only notifiable part is the electrical work, such as a new circuit. A registered competent person, such as an NICEIC-approved contractor, can self-certify it.

Is a new circuit for air conditioning notifiable?

Yes. The Planning Portal lists installing a complete new circuit as notifiable electrical work in homes in England.

Does Part L apply to air conditioning?

Comfort cooling is a fixed building service under Part L, which sets minimum efficiencies and asks for effective controls, commissioning and operating information.

Does air conditioning count as ventilation?

No. A standard split system recirculates room air. Ventilation rules under Part F apply when ventilation itself is installed or changed.

Where does the water from air conditioning go?

Through a condensate drain to an outside drain, gully or internal waste with a trap, or via a condensate pump where gravity won’t work.

Related services

More advice

This guide is general information, checked against the sources linked on 30 October 2026. It isn’t legal, tax or financial advice. Rules, grants and product ranges change, so check the current position before you rely on it.