Continuous extract fans (dMEV) in West Midlands

A dMEV (decentralised mechanical extract ventilation) fan is a low-energy extract fan that runs continuously at a quiet trickle speed and boosts automatically when it senses humidity or a light switch. Because it never fully switches off, moisture is removed steadily instead of building up between showers.

The West Midlands 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.

dMEV fans in the West Midlands at a glance

Area: West Midlands
Towns listed: 32, largest Birmingham
Postcode districts: B8, B9, B6, B7, B28 and B90
Price region: West Midlands
Survey: Free survey (UK mainland)

What the work involves

Landlords and housing associations often choose them because tenants cannot switch them off and forget them. Under Approved Document F, continuous mechanical extract systems need commissioning: the airflow on both trickle and boost is measured and recorded. We do that as part of the job, so you have a record for building control, a landlord file or a future buyer.

Kitchen

Higher-rated continuous fans where a ducted hood is not practical.

Whole-home dMEV upgrade

Every wet room converted at once, with trickle vents checked in the habitable rooms.

Commissioned and recorded

Trickle and boost rates measured and written on a commissioning sheet.

Guide prices in the West Midlands

Continuous extract fans (dMEV) guide prices in the West Midlands
Work	Guide price
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£345–£595 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£145–£295 inc VAT

These ranges use our West Midlands rates. Prices include VAT at 20%. You get a fixed written price before any work is booked.

Common reasons people call

Building control has asked for continuous extract
Occupants switch fans off because of noise
Mould keeps returning in a bathroom with a working fan

Rules in England

In England, ventilation is covered by Part F of the Building Regulations and its guidance, Approved Document F (2021 edition). It sets extract rates for kitchens, bathrooms and utilities and asks for mechanical ventilation to be commissioned and recorded.

How the job runs

Survey
Specify
Fit
Commission
Record

Towns we cover in the West Midlands

Questions about continuous extract fans (dMEV) in the West Midlands

Are prices different in the West Midlands?

Our guide prices are adjusted by region. In the West Midlands we use West Midlands rates, so continuous-running extract fan (dMEV) with humidity boost, flow tested is typically £345 to £595 inc VAT per fan.

Do I still need trickle vents?

Yes. With continuous extract, Approved Document F still expects background ventilators in habitable rooms so replacement air can get in.

Can dMEV fans be fitted where a fan already exists?

Usually yes. Most fit the existing hole or duct, which keeps the cost and mess down.

Is the survey free in the West Midlands?

For new installations on the UK mainland, yes. The survey is free and the quote that follows is fixed and in writing. Servicing, testing and repair visits are charged, and we confirm the cost before booking.

Which rules apply to ventilation in the West Midlands?

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.

Continuous extract fans (dMEV) in the West Midlands