Air conditioning installation in Westminster

Westminster City Council has 56 conservation areas covering over 76% of the City, so most homes here are in one. Under the heat pump permitted development rules, a unit in a conservation area cannot go on a wall or roof facing the street, and a cooling only unit is never covered. A single flat in a block does not have its own permitted development right either, and blocks with shops on the ground floor, common on Marylebone High Street and Edgware Road, do not count as a block of flats at all. Expect a planning application for most flat installs.

Noise is the other test. Westminster's noise technical guidance asks that, in areas where background noise is already high, new plant should be 10 dB below the lowest background level at the nearest noise sensitive window, and 15 dB below if the noise is tonal. That is a demanding standard, so the unit model, its position, any screen and the distance to the nearest bedroom window are chosen together, and the noise figures go in the application.

Most mansion blocks in Maida Vale, Marylebone and St John's Wood are run by a managing agent for the freeholder. A licence for alterations is the usual route, and agents commonly ask for drawings, the unit specification, noise data, the condensate route, method statements and proof of the installer's F-gas certification and insurance. Some blocks allow units only in the rear lightwells, some only on the main roof, and a few have a block wide policy that limits units altogether. Getting the agent's rules early saves weeks.

Inside the flat, high ceilings and solid walls help. Pipes can often run above a corridor or in a neat cover along a cornice line to the rear room, and the indoor unit can go on the internal side of a front room so the street elevation stays untouched.

The Met Office recorded 40.2°C at St James's Park on 19 July 2022, the joint UK record, a short walk from Pimlico and Mayfair. Central Westminster is also deep in London's heat island, where stone, brick and traffic hold heat into the night. Top floor flats under mansion block roofs and south facing rooms in Bayswater are the ones that call for cooling first. Offices in Victoria and Soho have similar needs, with the extra step of landlord approval for any roof plant.