Continuous extract fans (dMEV) in Cheshire

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.

Every job in Cheshire gets a written quote before it starts and a commissioning record when it finishes. We cover Warrington, Chester, Crewe, Ellesmere Port Town and Widnes and the villages around them.

dMEV fans in Cheshire at a glance

Area: Cheshire
Towns listed: 24, largest Warrington
Postcode districts: CW1, CW2, CH60, CH62, SK2 and SK7
Price region: North West
Survey: Free survey (UK mainland)

How we do it

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. Under Approved Document F, continuous mechanical extract systems need commissioning: the airflow on both trickle and boost is measured and recorded.

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.

Whole-home dMEV upgrade

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

Guide prices in Cheshire

Continuous extract fans (dMEV) guide prices in Cheshire
Work	Guide price
Continuous-running extract fan (dMEV) with humidity boost, flow tested (per fan)	£330–£575 inc VAT
Airflow testing and commissioning sheet for extract fans (up to 6 fans) (per home)	£140–£280 inc VAT

North West 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

You manage rental homes and want ventilation that cannot be switched off
You are refurbishing several wet rooms at once
An energy retrofit has made the house more airtight

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

Survey
Specify
Fit
Commission
Record

Towns we cover in Cheshire

Questions about continuous extract fans (dMEV) in Cheshire

Which towns in Cheshire do you cover?

All of Cheshire, including Warrington, Chester, Crewe, Ellesmere Port Town and Widnes. If your town is not listed, send the postcode and we will confirm.

What is the difference between dMEV and MEV?

dMEV uses one small fan in each wet room. MEV uses one central fan, usually in the loft, ducted to all the wet rooms. Both run continuously.

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.

Are prices different in Cheshire?

Our guide prices are adjusted by region. In Cheshire we use North West rates, so continuous-running extract fan (dMEV) with humidity boost, flow tested is typically £330 to £575 inc VAT per fan.

Is the survey free in Cheshire?

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.