When Is Ventilation Certification Required?

A new extractor fan may clear steam from a bathroom. A properly designed and commissioned ventilation system does far more: it protects the fabric of the building, reduces excess humidity and helps families breathe cleaner air. But when is ventilation certification required, and when is a simple installation record enough?

For Irish homes and commercial properties, the answer depends on the type of building work, the ventilation system being fitted and the compliance route for the project. Certification is not just paperwork to complete at the end. It is evidence that the system can deliver the airflow it was designed to provide.

When Is Ventilation Certification Required in Ireland?

Ventilation certification is generally required where ventilation work forms part of a project that must comply with the Irish Building Regulations, particularly Technical Guidance Document F – Ventilation. This commonly includes new dwellings, major renovations, material alterations, changes of use and many multi-unit or commercial projects.

Where a mechanical ventilation system is specified to meet Building Regulations, it should be installed, tested, balanced where necessary and commissioned. The completed records demonstrate that the system meets the required airflow performance in the finished building, rather than simply relying on the fan or unit’s published specification.

The exact documents required can vary. A project may need a commissioning report, airflow test results, an installation checklist, design information and, on projects covered by the Building Control (Amendment) Regulations, supporting documentation for the Completion Certificate process. Your assigned certifier, designer or building control professional can confirm the documentation route for the individual project.

Certification Is Different From Buying a Certified Product

A ventilation unit may be tested and certified by its manufacturer, but that does not certify the completed installation. Performance changes once equipment is placed in a real property. Duct lengths, bends, grille selections, poor sealing, blocked vents and incorrect settings can all reduce airflow.

That distinction matters. A high-quality heat recovery ventilation unit can still underperform if its ductwork is poorly routed or the supply and extract valves are not balanced. Equally, a powerful extractor fan can create noise without moving sufficient air from the room where moisture is produced.

A site-specific ventilation certificate or commissioning report confirms the performance of the installed system. It records the measured airflow and, where relevant, the adjustments made to bring the system into line with the design requirement.

Projects That Commonly Need Ventilation Certification

New-build homes

New dwellings need a ventilation strategy that satisfies TGD F-2022 requirements. Whether the design uses centralised mechanical ventilation with heat recovery, demand-controlled ventilation, continuous mechanical extract ventilation or another suitable approach, commissioning evidence is normally a key part of demonstrating compliance.

This applies to houses and flats. In airtight new homes, ventilation cannot be treated as an afterthought. The building is designed to retain heat, so it also needs a controlled route for moisture, odours and indoor pollutants to leave, while fresh air is brought in without unnecessary heat loss.

Extensions, renovations and airtightness upgrades

An extension or refurbishment does not automatically mean that every existing room requires a new certified system. However, certification may be needed if the works include a new ventilation installation or materially alter the building’s ventilation provision.

Common examples include converting an attic into a bedroom, creating a new bathroom or utility room, changing the use of a space, upgrading a property to improve airtightness or carrying out deep energy renovations. Replacing leaky windows, insulating walls and sealing draughts can improve comfort and energy efficiency, but it can also expose an inadequate ventilation system.

The right approach depends on the scope of the works. A competent assessment should consider the whole property, not just the newly finished room. Moisture travels, and mould often appears in the coldest or least ventilated part of the home.

Flats, rental properties and multi-unit schemes

For developers, landlords and property managers, documented commissioning is especially valuable. Blocks of flats and multi-unit developments often contain repeated layouts, shared design responsibilities and strict handover requirements. Clear airflow records help demonstrate that each dwelling has been checked individually.

Landlords also have a practical reason to retain ventilation documentation. If condensation or mould is later reported, a commissioning report provides a useful baseline for investigating whether the issue relates to system performance, maintenance, occupancy patterns or a separate building defect.

Commercial buildings and change-of-use projects

Commercial ventilation requirements vary according to use, occupancy and the nature of the works. Offices, retail units, hospitality venues, childcare settings and changing rooms can all require carefully designed ventilation. A change from storage to office accommodation, for example, can create a very different fresh-air requirement.

For these projects, certification may include more detailed design, commissioning and handover records. The building’s fire strategy, energy performance and controls also need to work alongside the ventilation design. One-size-fits-all equipment selection is rarely a safe route to compliance.

Like-for-like fan replacements

Replacing a failed bathroom or kitchen fan on a like-for-like basis does not always trigger a formal Building Regulations certification process. Yet it is still wise to check the installed airflow, duct condition and external termination. A replacement fan connected to a crushed flexible duct or a clogged grille will not solve a condensation problem.

If the replacement forms part of wider renovation work, or if a new system is being used to satisfy a regulatory requirement, commissioning documentation becomes much more relevant.

What Ventilation Certification Must Show

Good certification is based on measurement, not assumption. The installer should first confirm that the system has been fitted in accordance with the design and manufacturer guidance. Airflow is then measured at extract and supply points using suitable calibrated equipment.

For centralised systems, balancing is often required so that each room receives the intended airflow and the overall system operates correctly. Settings should be recorded, including boost operation where applicable. The report should identify the property, the system type, relevant airflow readings, the date of testing and the person or company responsible for commissioning.

The homeowner or building manager should also receive clear operation and maintenance information. Filters need changing, external grilles need keeping clear and controls need to be understood. Certification confirms performance at handover; regular maintenance helps retain it.

Why Testing Protects More Than Compliance

Ventilation testing is about the people living or working in the building. Inadequate extraction lets moisture linger after showers, cooking and clothes drying. Over time, that moisture can contribute to condensation, mould growth and damage to finishes, furnishings and timber.

Poorly balanced mechanical heat recovery ventilation can create a different set of problems, such as draughts, noise, stale bedrooms or unnecessary energy use. Commissioning identifies these issues before they become part of daily life.

There is also a financial benefit. Fixing airflow issues while installers are still on site is usually simpler than investigating mould months later, after decorating has been damaged and residents are frustrated. Measured results give builders, developers and homeowners a clear starting point rather than guesswork.

Plan the Evidence Before Work Starts

The easiest time to achieve certification is before ceilings are closed and finishes are completed. Ventilation design should be coordinated early with electrical works, structural elements, kitchen layouts and roof penetrations. This avoids inaccessible duct runs, unsuitable grille positions and last-minute substitutions that compromise airflow.

For a straightforward project, keep four essentials together: the ventilation design, product details, installation records and commissioning results. For larger projects, agree at the outset who will gather each document and who needs it at handover. Waiting until the end to ask for test records can delay completion and create unnecessary remedial work.

PureAir Solution can support this process from system selection and installation through to airflow testing, balancing and certification, helping projects across Ireland move from a ventilation plan to documented performance.

If you are planning building work, do not wait for condensation to tell you that ventilation was overlooked. Ask early what evidence your project will require, then make sure the system is designed and tested to keep the property healthy long after the builders have left.