Airflow testing and commissioning in Greater London

Airflow testing measures how much air each fan or valve actually moves, using a calibrated flow hood, and records it against the required rates. It is how you prove a ventilation system works, and for new homes it is part of the building regulations.

Greater London has every kind of building, from old terraces to new estates and business parks, and every job is designed around the building in front of us, not a standard kit.

Airflow testing in Greater London at a glance

Area: Greater London
Towns listed: 216, largest Brent
Postcode districts: IG2, IG4, RM10, RM12, SE24 and SW2
Price region: London
Survey: Charged visit, price agreed first

How we do it

Approved Document F expects mechanical ventilation in new dwellings to be tested with a flow device that has been calibrated within the last 12 months, and the results recorded on a commissioning sheet. The person commissioning should be registered with a competent person scheme for ventilation or show evidence of competence; we tell you who will sign your sheet when we quote. Testing is also useful outside new builds: it shows landlords and homeowners whether existing fans meet the rates, and it is the first step in rebalancing an MVHR system that no longer feels right.

Extract fan tests

Each fan measured and compared with the Part F rate for the room.

MEV and dMEV commissioning

Trickle and boost rates measured and set.

MVHR commissioning

Supply and extract at every valve measured and balanced.

Guide prices in Greater London

Airflow testing and commissioning guide prices in Greater London
Work	Guide price
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£175–£355 inc VAT
MVHR or MEV commissioning test, every terminal measured and recorded (per system)	£295–£475 inc VAT
Rebalance and recommission an existing MVHR system (per system)	£295–£525 inc VAT

London rates shown. Prices include VAT at 20%. The fixed price is confirmed in writing after we have seen the job.

When to get it looked at

Building control needs a commissioning sheet
You are selling a new build and the paperwork is missing
Fans seem weak and you want evidence

Rules in England

In England, ventilation is covered by Part F of the Building Regulations and its guidance, Approved Document F (2021 edition). For homes, it sets minimum extract rates such as 15 litres a second for a bathroom and 30 or 60 for a kitchen, and expects mechanical systems to be airflow-tested.

How the job runs

Book
Measure
Adjust
Record
Advise

Towns we cover in Greater London

Questions about airflow testing and commissioning in Greater London

Is the survey free in Greater London?

This is a charged visit because it is servicing, testing or repair work. We tell you the cost before booking. Surveys for new installations on the UK mainland are free.

What equipment is used?

A flow hood that fits over the fan or valve and measures airflow in litres a second, calibrated within the last 12 months.

What happens if a fan fails the test?

We explain the likely cause, such as an undersized fan or a crushed duct, and quote to fix it. Many failures are cheap to put right.

Which rules apply to ventilation in Greater London?

In England, ventilation in new and altered homes is covered by Approved Document F of the Building Regulations. Landlords also have duties under the Housing Health and Safety Rating System, and workplaces must be ventilated under the Workplace (Health, Safety and Welfare) Regulations 1992.

Which towns in Greater London do you cover?

All of Greater London, including Brent, Islington, Westminster, Bexley and Barking. If your town is not listed, send the postcode and we will confirm.