Accountants for air conditioning and ventilation installers

For VAT, yes, substantially. Air source heat pumps are qualifying energy-saving materials, so installing one in residential accommodation is zero-rated until 31 March 2027 and 5% from 1 April 2027. Comfort cooling is not on the list and is standard rated. Both are inside CIS as installation of an air-conditioning or ventilation system — so the CIS answer is the same and the VAT answer is not. In practice that means a single job installing a heat pump and a comfort cooling unit carries one CIS treatment and two VAT rates, and the invoice has to show which is which.

Yes, where the payment is within the scheme. The cost of manufacture or prefabrication is expressly excluded from the payment subject to deduction, alongside materials you directly incurred, consumable stores, fuel other than fuel for travelling, plant hire and the VAT you charged. It has to be identified on the invoice to do anything. An invoice reading “supply and install ductwork” as one figure gives the contractor nothing to exclude, and the contractor is the party HMRC expects to justify the materials figure — so it will estimate rather than take your word for it.

The scheme asks whether the payment is for a construction operation, not whether the work is regulated. Installing, altering or repairing an air-conditioning system in a building is a construction operation regardless of the certification the work requires. Servicing an existing system is repair and maintenance of the building's installed systems, which sits inside the same wording. F-Gas certification is a competence and environmental requirement that runs alongside the tax treatment rather than deciding it. Certification decides who may lawfully do the work; the scheme decides how the payment is taxed, and neither answers the other's question.

CIS does not distinguish by building type — it asks whether the operation is construction. Installing air conditioning in an office is as much a construction operation as in a house. What changes with the building is the VAT: the zero and reduced rates concern dwellings, relevant residential and relevant charitable use, so commercial work is generally standard rated and therefore inside the reverse charge where the other conditions hold. The exception on a commercial building is a relevant residential or relevant charitable use, which can bring the zero or reduced rate back into play — so the question is what the building is used for, not whether it is an office.