Continuous extract fans (dMEV) in Lothians

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.

The Lothians 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 the Lothians at a glance

Area: Lothians, Scotland
Towns listed: 13, largest Livingston
Postcode districts: EH52, EH19, EH22, EH49, EH51 and EH47
Price region: Scotland
Survey: Free survey (UK mainland)

What continuous extract fans (dMEV) involves

Whole-home dMEV upgrade

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

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.

Guide prices in the Lothians

Continuous extract fans (dMEV) guide prices in the Lothians
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–£285 inc VAT

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

When to get it looked at

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 Scotland

Scottish projects follow the Technical Handbooks (section 3, Environment) under the Building (Scotland) Regulations, usually with a building warrant. Extract and whole-home rates are designed to the Scottish standards and measured at handover.

How the job runs

Survey
Specify
Fit
Commission
Record

Towns we cover in the Lothians

Questions about continuous extract fans (dMEV) in the Lothians

Are prices different in the Lothians?

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

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.

Is the survey free in the Lothians?

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 the Lothians?

In Scotland, ventilation is covered by section 3 of the Building Standards Technical Handbooks. Private rented homes must meet the Repairing Standard, and workplaces must be ventilated under the Workplace (Health, Safety and Welfare) Regulations 1992.

Continuous extract fans (dMEV) in the Lothians