Ventilation commissioning certificates under Approved Document F

What this certificate covers

Ventilation commissioning certificates follow Approved Document F, Volume 1: Dwellings (2021 edition) — the current government guidance on Part F of the Building Regulations 2010, in force since 15 June 2022. It groups the ventilation a new or altered home needs into three approaches: natural ventilation, using background ventilators plus intermittent extract in kitchens, bathrooms and utility rooms, for less airtight dwellings only; continuous mechanical extract ventilation (MEV); and mechanical ventilation with heat recovery (MVHR). Once a system is installed, it has to be commissioned: checked and tested to confirm it actually performs as designed, with the results recorded and a copy given to whoever needs it. A ventilation certificate is that commissioning record — what was installed, that it was tested, and what the results were, not just that a fan was fitted.

Who issues one, and when it's needed

A competent installer — an M&E contractor, a ventilation specialist, or a multi-trade firm carrying out the ventilation work alongside a rewire or a wider retrofit — commissions the system once installation is complete and issues the certificate. It's needed wherever Approved Document F applies: new dwellings, and material alterations or conversions (such as an HMO conversion) that trigger a ventilation requirement under the current Building Regulations guidance.

This section describes Approved Document F as general information about what ventilation commissioning is and when it applies. Whether a specific job needs a particular system, and what flow rates or configuration it needs to achieve, is a decision for the competent person carrying out the design and installation and, where relevant, the building control body — not something this page can tell you for a specific property.

The statutory paperwork

Commissioning carries two separate notice duties to the local authority building control body under the Building Regulations 2010, not just good practice: the measured air flow rates for a new dwelling are due within five days of the final test (regulation 42), and a commissioning notice confirming the system has been tested and adjusted is due alongside the completion notice or within 30 days of finishing the work (regulation 44). Where mechanical ventilation is commissioned, the Part L (energy efficiency) commissioning notice can be combined with the Part F one.

A copy of the completed commissioning sheet — the measured air flow rates, the equipment used, and the commissioning engineer's signed declaration — has to be given to the owner of the dwelling. That's the record NexCert's certificate is built to produce.

Part O (overheating), where it applies, can require a higher purge-ventilation standard than Part F's minimum — where both apply on a job, the higher standard governs. This page describes the general duties; what a specific job needs is a decision for the competent person carrying out the design and installation.

How NexCert issues this certificate

The installer records the commissioning check on a phone or tablet, on site, with the form working offline and resuming if signal drops — what system was installed, what was tested, and the results. Flow rates are measured with a calibrated air-flow device, accurate to within ±5% and calibrated in the last 12 months at a UKAS-accredited centre, and recorded in litres per second; continuous systems (MEV, MVHR) are balanced to their design flow rate at each terminal before the reading is taken. Where a supervisor needs to check and sign off before the certificate goes out, that sign-off happens remotely, from a desktop. The finished certificate is delivered with an evidence trail: what was commissioned, by whom, and when it was signed off — the record to hand to the customer, or to keep on file if building control or a future sale asks for it.

There are fields for your own NICEIC, NAPIT, SELECT or Gas Safe registration number, at both company and individual engineer level, on every certificate NexCert issues.

Ventilation alongside the rest of the job

Ventilation commissioning is frequently one part of a job that also involves electrical work or domestic fire alarm work — a rewire, a loft conversion, or an HMO fit-out. If the same job involves electrical installation or condition reporting, see EICR; if it involves fitting a domestic fire alarm system, see fire alarm design, installation and commissioning. All three sit inside NexCert's electrical product line, in the same workspace, so a multi-trade job doesn't need separate software for each certificate.