Continuous extract fans (dMEV) in West Sussex

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.

West Sussex 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 West Sussex at a glance

Area: West Sussex
Towns listed: 16, largest Crawley
Postcode districts: BN12, BN16, RH6, RH10, BN6 and BN45
Price region: South East
Survey: Free survey (UK mainland)

What continuous extract fans (dMEV) involves

dMEV fans replace ordinary intermittent fans in bathrooms, kitchens, utility rooms and WCs. On trickle speed they are barely audible and use very little power; on boost they reach the higher continuous-extract rates in Approved Document F (in England, at least 13 litres a second for a kitchen, 8 for a utility room or bathroom and 6 for a WC). Landlords and housing associations often choose them because tenants cannot switch them off and forget them.

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 West Sussex

Continuous extract fans (dMEV) guide prices in West Sussex
Work	Guide price
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£380–£650 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£160–£325 inc VAT

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

Signs it is time to call us

Occupants switch fans off because of noise
Mould keeps returning in a bathroom with a working fan
You manage rental homes and want ventilation that cannot be switched off

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 West Sussex

Questions about continuous extract fans (dMEV) in West Sussex

Which towns in West Sussex do you cover?

All of West Sussex, including Chichester, Burgess Hill, Crawley, Worthing and Bognor Regis. If your town is not listed, send the postcode and we will confirm.

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.

Are prices different in West Sussex?

Our guide prices are adjusted by region. In West Sussex we use South East rates, so continuous-running extract fan (dMEV) with humidity boost, flow tested is typically £380 to £650 inc VAT per fan.

Is the survey free in West Sussex?

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.