Air conditioning in the City of London

City offices are usually let floor by floor. The landlord owns the roof, the risers and the plant decks, and most leases need a licence for alterations for any new air conditioning. Base build systems in larger towers are often run by the landlord, so a tenant adding cooling to a meeting room or comms room must connect to agreed capacity or add a separate system in an approved location.

Common jobs are extra cooling for meeting rooms and comms cupboards, ceiling cassettes in a Cat B fit out, and replacing older split systems in smaller buildings around Farringdon and Aldgate. Working hours, lift bookings and loading bay slots are set by the building manager, and noisy drilling is often limited to early mornings or weekends.

Under the Energy Performance of Buildings regulations, air conditioning systems with an effective rated output of more than 12kW must be inspected by an accredited energy assessor at least every five years. This is the TM44 inspection set out in the government's guide. Bigger systems often also hold enough refrigerant to need regular F-gas leak checks by law, with records kept by the operator. Any work on the refrigerant must be done by an engineer with an F-gas qualification working for a certified company, so building managers will ask to see the company certificate.

The City has 28 conservation areas, and much of its housing sits in or next to them. At the Barbican, external alterations are tightly controlled because the estate is listed, so external units on balconies or façades are generally not an option without consent. Portable or internal solutions, or a unit approved through the estate's own process, may be the realistic routes. In converted office flats, the building manager and the lease will set out where any outdoor unit can go.

Many City offices inherit air conditioning from a previous tenant, often with patchy records. When you take on a floor, ask the landlord or outgoing tenant for the installation details, service history, F-gas leak check records and any TM44 report. A service early in your occupation shows what condition the system is in, and whether any units use an older refrigerant that will be harder to support. Agree with the landlord who is responsible for maintaining each system, because in some buildings plant is maintained under the service charge.