How does an MEV System Improve Indoor Air Quality?

A Mechanical Extract Ventilation (MEV) system is a very popular low energy unit that provides continuous extract ventilation from multiple extract points drawing out moisture-laden air from the wet rooms whilst minimising humidity to other rooms providing good indoor air quality and creating a healthier living environment for you and your family.

How does a MEV work?

A Mechanical Extract Ventilation (MEV) replaces your normal bathroom fans to a single quieter and more powerful fan installed in the roof space or cupboard in dwellings with up to 6 wet rooms (Bathrooms & Kitchens)

Extracting damp and moist air from these rooms will improve indoor air quality and reduce moisture from building up which could lead to condensation, damp and mould problems.

The unit is connected via a system of solid rigid, flexible or semi rigid ducting which connects each wet room to the MEV unit and one external duct to outside.

The MEV unit runs continuously at a low rate providing continuous extraction ventilation and the speed can be manually increased if required with a boost switch or automatically with internal sensors

Air can be supplied by either the use of trickle vents fitted to your windows or the use of a positive ventilation unit PIV

We recommend installing a MEV system over multiple extractor fans as it provides continuous ventilation, is much quieter and more economical to run one fan instead of multiple fans.

What is Demand Control

Demand control is how the unit is set to increase speed and performance when or if it is required,

The most popular is the use of an internal humidity sensor that increases the speed of the unit when the total humidity of the extracted air exceeds its setting of normally 70%

Another option is the installation of individual humidity or Co2 sensors in the ductwork or air valves of each bathroom allowing you to individually increase the speed to only the room that needs the extra extraction

What is the difference between A MEV and MVHR

A MEV will only extract and requires either trickle vents or a positive ventilation unit to bring air into the property

A mechanical ventilation heat recovery (MVHR) system both extracts and supplies filtered air and recovers up to 90% of the normally wasted heat reducing your heating bills and all the air if fully controllable

The below diagram shows the airflow through a house with an MEV system installed. The air is extracted from the kitchen and bathroom and to the unit that is situated in the loft space, the extracted air is then exhausted out through a grill on the outside wall.


Benefits of a MEV System

You might be wondering, what can an MEV system for me? There are many benefits to installing a ventilation system in your home. Benefits of a MEV system include:

  • Eliminates condensation, dampness and mould growth
  • Removes musty odours
  • Can extract from up to 6 wet rooms
  • Extractor vans are not required
  • Low running costs & low-energy operation
  • Quiet operation
  • Reduces symptoms for asthma & allergy sufferers
  • Low specific fan power
  • Easy maintenance

Is an MEV System Suitable for My Property?

MEV units are designed for the simultaneous ventilation of separate areas in the home or a wide range of commercial applications.

They are also an ideal ventilation solution in renovation and new build buildings where there is only one external wall or have restricted roof openings

Our MEV Systems

Our Popular multi use MEV unit Passivent A151DC-G is on special offer! (Summer 2019) This unit is suitable for extracting from a kitchen and up to 4 wet rooms. The unit features three adjustable speeds and an air capacity of 275m3/hr @120Pa. The unit can be installed on the floor, wall or ceiling and the spigot orientation is interchangeable for even more installation possibilities. This great deal is one not to be missed!

We also have a range of popular MEV units from leading manufacturers including Duco, Vent-Axia, Xpelair and Domus! Check out our video for the Vent Axia MVDC-MS unit!

If you require more information on MEV or other ventilation systems, please contact our sales and technical teams on 028 2827 5150. Our teams of ventilation experts will be happy to answer any questions and enquires, alternatively you can fill in our quick online contact form.