Section 20 of the Landlord and Tenant Act 1985 can require a landlord to consult leaseholders before carrying out qualifying works in a block and recovering the cost through the service charge. Air conditioning for the building, or works that include it, can fall into that process when the works qualify. Thresholds and the steps are set in the rules and they change. Check the current position with the Leasehold Advisory Service at https://www.lease-advice.org/ This page does not state a legal fee. A leaseholder fitting a split inside their own flat is usually a licence-to-alter question, which is a different gate from Section 20.
Qualifying works and the service charge
The consultation exists so leaseholders see qualifying works, and the costs the landlord wants to put through the service charge, before the money is spent. Skipping a consultation that was required can limit what the landlord is allowed to recover. That is a landlord and leaseholder process, not a discount on a domestic split. Whether a particular scheme is qualifying works depends on the works and on the current financial thresholds. This page will not invent those figures. The Leasehold Advisory Service is the public source to check, and the Act itself is on legislation.gov.uk.
A shared roof plant and a private sitting-room split
A block replacing a shared system, adding condensers on a roof, or running a major plant project is the sort of scheme where Section 20 comes up. Each leaseholder's share, the specification, and the observations process belong in that consultation. A leaseholder who wants one indoor unit in a sitting room still needs the lease to allow it, and usually written consent, plus a lawful place for the outdoor unit. That consent is not Section 20. Both can matter in the same year if the block is also doing its own works. Do not start drilling because a neighbour did.
Papers that name the cost, not a fee invented here
The service charge impact is whatever the consultation papers say, divided as the lease says. Challenge routes exist. They are not a number this page can print. Budget your own flat's install separately, as a surveyed split with access and consent, using the illustrations on other cost pages only as bands.
Frequently asked questions
Does every flat install need Section 20?
No. Section 20 consultation can apply when the landlord carries out qualifying works and recovers them through the service charge. A private install in your flat is usually about the lease and consent. Check your papers, and check thresholds with the Leasehold Advisory Service.
What is the current cost threshold?
This page does not state one. Thresholds change. Use the Leasehold Advisory Service at https://www.lease-advice.org/ for the current rules.
Can the installer start while consultation runs?
Not if the works are the landlord's qualifying works and consultation is required. Wait until the process that applies to your block has been followed. A private flat still waits on written consent.
Is a licence to alter the same gate as Section 20?
No. Your own flat's install is often a licence to alter. Section 20 is about landlord works recovered through the service charge.
Does consultation replace an F-gas company or planning rules?
No. Whoever installs still needs an F-gas certified company for the refrigerant circuit. In England, outdoor units still face Planning Portal heat pump rules. Do not ask an installer to invent a legal fee.
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How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.