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HVAC commissioning: what a proper handover includes

Updated 23 October 2026 · SEO Dons Editorial

What is commissioning meant to prove?

Approved Document L describes commissioning as taking a system from a state of static completion to working order. BSRIA's wording is the advancement of an installation from static completion to full working order to the specified requirements. For each system, the guidance says commissioning includes setting to work; regulation, meaning testing and adjusting repetitively to achieve the specified performance; calibration; setting up and testing the associated automatic control systems; and recording the system settings and the performance test results that have been accepted as satisfactory.

The last item is the paper that matters. A system can look finished and still have no recorded evidence that it works.

What should a commissioning plan contain?

For large or complex projects, Part L guidance says a commissioning manager should be appointed, with competence meeting CIBSE's Commissioning Code M. The plan should identify the systems to test, the tests to complete, the schedule, roles and responsibilities, and documentation requirements. The building control body should be given the plan, so it can check commissioning as the work proceeds.

CIBSE's description of Code M follows a project from a commissionability review at design stage, through pre-functional tests, functional performance tests, integrated systems tests and training for users and operators, to handover of commissioning-related documentation, then fine tuning and seasonal testing in use. Part L notes an exception: where the only controls are on and off switches, that service does not need to be commissioned.

Which tests and standards apply to each part of the system?

Part L says commissioning follows CIBSE's Commissioning Code M, plus either the specific CIBSE Commissioning Codes or the specific BSRIA Commissioning Guides for each service.

PartWhere the method comes from
Refrigerant circuitBS EN 378-2 lists a strength pressure test, a tightness test and a functional test. CIBSE Code R is a guide to good practice for commissioning refrigeration plant in air conditioning. Makers add their own lists: Daikin's VRV IV manual checks that supply voltage matches the nameplate and that no fuse or protection device has been bypassed, and requires a test run after first installation.
Air distributionCIBSE Code A and BSRIA BG 49/2024, which explains how to functionally test and regulate ventilation systems. Where fans exceed 1 m3/s, Part L asks for ductwork leakage tests to BESA DW/143 and DW/144.
Chilled waterCIBSE Code W and BSRIA BG 2/2010, a step-by-step description of commissioning procedures.
ControlsCIBSE Code C, and Part L's requirement to set up and test the associated automatic controls.

What refrigerant and electrical records should arrive?

Anyone installing a product with regulated F gas must label it, and the label must show the industry name for the gas, its mass in kg, its weight in tonnes of carbon dioxide equivalent and its global warming potential. For stationary air conditioning holding 5 tonnes CO2e or more, the operator must keep records of the quantity and type of gas installed, the company details and certificate number of anyone used to install, service or decommission the equipment, and the dates and results of mandatory leak checks. The F-gas certificate check guide shows how to verify the company.

Makers ask for more. Daikin's checklist asks whether the added refrigerant is recorded on the charge label, and says to keep a record of the installation date and the field settings. On the electrical side, the installer's certificate and test schedules belong in the pack; the electrical supply guide covers what is certified.

What do the Building Regulations notice and handover pack contain?

In England, regulation 44 requires a notice confirming the fixed building services were commissioned in accordance with a procedure approved by the Secretary of State. Approved Document L says it should confirm that the commissioning plan was followed, that all systems were inspected in an appropriate sequence and to a reasonable standard, and that test results confirm performance is reasonably in accordance with the actual building design, with written commentary on shortfalls. It goes to the building control body and the owner within five days where a building notice or full plans went to a local authority, and within 30 days in other cases. A person registered with a competent person scheme may give it.

Regulation 40 separately requires the owner to receive sufficient information about the building, the services and their maintenance requirements not later than five days after completion. The guidance says to provide operating and maintenance instructions in a building log book following CIBSE's TM31, with a copy of the completed commissioning records. In an existing building, a complete new or replacement system's energy performance is assessed and documented and handed over with the manufacturer's literature. Where CDM 2015 applies, the principal designer prepares the health and safety file and passes it to the client at the end.

The 2021 edition incorporating 2023 amendments is cited here. The 2026 edition takes effect on 24 March 2027 for most work in England and keeps the commissioning plan and notice. Wales has a separate version of regulation 44, and Scotland and Northern Ireland have their own building regulations.

What should a handover checklist say?

ItemAsk for
Plan and resultsThe commissioning plan, signed test results and the settings accepted as satisfactory
Refrigerant testsStrength pressure, tightness and functional test results
F-gas label and recordLabel details, quantity and type installed, installer's certificate details
Air and water balancingMeasured results against design, with written commentary on shortfalls; ductwork leakage results where required
ControlsSchedules, setpoints and zones tested, and the field settings recorded
ElectricalInstallation certificate with inspection and test schedules
Operation and maintenanceBuilding log book entry, manuals and warranty conditions
Statutory papersCopy of the commissioning notice and the health and safety file
TrainingEvidence that users and operators were trained
Seasonal testingA dated plan for fine tuning and seasonal testing in use

The contract is where final payment is tied to these items, so it should say which records release it. The quote comparison guide covers commissioning as a priced line.

What happens after handover?

CIBSE's Code M includes fine tuning and seasonal testing in use. BSRIA's Soft Landings framework describes graduated handover so operators have more time to understand interfaces and systems before occupation, then post-occupancy evaluation no sooner than 12 months after handover, repeated at 12 month intervals and ending in a final review at month 36. The installation timeline guide shows where these stages fall. Readers planning an installation can see the commercial air conditioning installation page and send an enquiry through the site's form.

Sources

Common questions

Is a tick sheet enough as a commissioning record?

Part L's notice rests on test results confirming the system performs reasonably in accordance with the building design, with written commentary where it does not. A sheet that ticks satisfactory without measured values would not show that, so the records should carry the readings alongside the plan.

Do small split systems need commissioning records?

Part L says a fixed building service whose only controls are on and off switches does not need to be commissioned. F-gas duties are separate: any installed product with regulated F gas must still be labelled, and operator records apply above the 5 tonnes CO2e threshold.

Who can give the commissioning notice?

The person carrying out the work gives it to the building control body and the owner. Where the work is installed by a person registered with a competent person scheme, that person may give it. The timing is five days in some cases and 30 days in others, as set out in Approved Document L.

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