Continuous extract fans (dMEV) in Somerset

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 Somerset gets a written quote before it starts and a commissioning record when it finishes. We cover Frome, Burnham-on-Sea, Bath, Weston-super-Mare and Taunton and the villages around them.

dMEV fans in Somerset at a glance

Area: Somerset
Towns listed: 19, largest Bath
Postcode districts: BS11, BS20, BA11, TA8, TA9 and BS21
Price region: South West
Survey: Free survey (UK mainland)

What the work 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 Somerset

Continuous extract fans (dMEV) guide prices in Somerset
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–£305 inc VAT

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

Signs it is time to call us

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 Somerset

Questions about continuous extract fans (dMEV) in Somerset

Which rules apply to ventilation in Somerset?

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.

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.

Which towns in Somerset do you cover?

All of Somerset, including Frome, Burnham-on-Sea, Bath, Weston-super-Mare and Taunton. If your town is not listed, send the postcode and we will confirm.

Are prices different in Somerset?

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