Part F Ventilation Testing: The Complete Guide

Extractor fans and whole-home systems

Part F is the part of the Building Regulations covering ventilation. An extractor fan test measures the airflow from the installed system. A fan making a noise does not tell you how much air it is actually moving.

We test individual kitchen, bathroom and utility extract fans, continuous local extract fans (dMEV), central mechanical extract ventilation (MEV), and mechanical ventilation with heat recovery (MVHR). MVHR supplies fresh air as well as extracting stale air. Tell us which system you have, or send photographs and the make/model if you are unsure.

Prepare for your visit

Book early enough to allow time for adjustments before handover. Fans, ductwork, terminals and controls should be installed, connected and accessible, with power available. For whole-home systems, have the ventilation design and intended airflow rates ready where available.

Check that duct connections are secure, flexible ductwork is not crushed or kinked, and terminals and filters are clear. The system needs suitable replacement-air routes as well as an extract route. We will discuss the required test conditions, access and any incomplete work before the visit.

Testing, commissioning and records

We measure the installed airflow and compare it with the requirements applicable to your system and project. Where commissioning is included, we adjust suitable settings and balance the system as required within the agreed scope.

You receive the relevant airflow results and commissioning records for the work completed, to support your project documentation and Building Control submission. Tell us about reporting formats, plot references and handover deadlines when requesting a quote. Records describe the tested installation; any issues needing further work will be explained.

If a fan or system falls short

Low airflow can result from an unsuitable fan, incorrect settings, restrictive ductwork, loose connections, blocked terminals or insufficient replacement air. Our construction background helps us investigate the installation and explain practical next steps.

We discuss adjustments or remedial work and any retesting needed. Installation repairs and additional visits depend on the agreed scope. Our real-site article shows why measuring airflow matters: four extractor fan faults found on site.

From a self-build to a development programme

We help self-builders understand the test and prepare for the visit. For developers and Tier 1 contractors, we can discuss coordinated testing across plots, phases and handover dates, with clear property references and reporting requirements.

We are NAPIT Competent Person Scheme members and use FlowFinder MK2 powered-flow equipment. Our practical experience as carpenters, bricklayers, site managers and general builders helps us communicate findings to the people carrying out the work.

Common questions

Is an extractor fan test the same as Part F testing?

Extractor airflow measurement can be part of the testing and commissioning needed for Part F. The scope depends on your installation. Send us the request from Building Control if you are unsure what is required.

Do I need an airtightness test as well?

They measure different things: airtightness testing measures leakage through the building fabric; ventilation testing measures airflow through the ventilation system. Tell us if you need both so we can discuss coordinated arrangements.

What will it cost?

The quote depends on the system, number of fans or properties, location, access and whether testing, commissioning or investigation is required. We confirm the scope before booking.

What is changing in 2027?

The readiness information above relates to the 2026 guidance for England and its transition arrangements. The requirements for your project depend on the applicable edition. Read the official Approved Document F guidance.

Request a ventilation testing quote

Send your site postcode, number of properties, system type or fan details, project stage and preferred dates. Include the ventilation design or the request you have received if available. We support East Anglia projects and can discuss UK-wide programmes.

Request a quote or discuss your testing programme →