Continuous extract fans (dMEV) in Norfolk

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.

Our team is based in Great Barr, Birmingham, and we work throughout Norfolk, from Great Yarmouth, King's Lynn, Thetford, Bowthorpe and East Dereham. The survey is free for new installations on the UK mainland, and the quote that follows is fixed and in writing.

dMEV fans in Norfolk at a glance

Area: Norfolk
Towns listed: 11, largest Norwich
Postcode districts: IP21, IP22, NR16, NR17, NR30 and NR31
Price region: East of England
Survey: Free survey (UK mainland)

What continuous extract fans (dMEV) 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.

Commissioned and recorded

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

Bathroom and en-suite

Through-wall or ceiling fans with humidity-controlled boost.

Kitchen

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

Guide prices in Norfolk

Continuous extract fans (dMEV) guide prices in Norfolk
Work	Guide price
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£360–£625 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£150–£310 inc VAT

Guide prices using East of England rates. Prices include VAT at 20%. A guide price is not a quote: we confirm a fixed price in writing first.

Common reasons people call

Mould keeps returning in a bathroom with a working fan
You manage rental homes and want ventilation that cannot be switched off
You are refurbishing several wet rooms at once

Rules in England

English building work follows Approved Document F (2021 edition) for ventilation rates, installation and commissioning. 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

Survey
Specify
Fit
Commission
Record

Towns we cover in Norfolk

Questions about continuous extract fans (dMEV) in Norfolk

Are prices different in Norfolk?

Our guide prices are adjusted by region. In Norfolk we use East of England rates, so continuous-running extract fan (dMEV) with humidity boost, flow tested is typically £360 to £625 inc VAT per fan.

Is it expensive to run a fan all the time?

No. dMEV fans use very little electricity on trickle speed, typically a few watts, so running costs are low compared with the condensation and mould they prevent.

Are continuous fans noisy?

A correctly sized dMEV fan is very quiet on trickle; most people only notice it on boost. Noise usually means the wrong fan or a poor duct.

Is the survey free in Norfolk?

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 Norfolk?

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.