Continuous extract fans (dMEV) in Hampshire

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.

Across Hampshire the job is priced the same way wherever you are: what is fitted, how long it takes and how far we travel. Towns we cover include Winchester, Southampton, Portsmouth, Basingstoke and Gosport.

dMEV fans in Hampshire at a glance

Area: Hampshire
Towns listed: 34, largest Southampton
Postcode districts: SO22, PO7, PO9, SP10, SP11 and PO14
Price region: South East
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.

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 Hampshire

Continuous extract fans (dMEV) guide prices in Hampshire
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

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

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. 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 Hampshire

Questions about continuous extract fans (dMEV) in Hampshire

Which rules apply to ventilation in Hampshire?

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.

How much does a continuous extract fan cost?

A dMEV fan usually costs £345 to £595 including VAT per room, supplied, fitted and commissioned. Converting several rooms in one visit brings the cost per fan down.

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.

Which towns in Hampshire do you cover?

All of Hampshire, including Winchester, Southampton, Portsmouth, Basingstoke and Gosport. If your town is not listed, send the postcode and we will confirm.

Are prices different in Hampshire?

Our guide prices are adjusted by region. In Hampshire 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.