Skip to main content

What is MEV and How Does it Work?

Date: 07 June 2021


What is MEV and How Does it Work?

Here are all of the questions our clients regularly ask about MEV (Mechanical Extract Ventilation).

What is MEV? 

MEV is a central extract system that removes stale, moist air from wet rooms within the home (such as bathrooms, shower rooms, utility rooms and kitchens), with no need for individual extractor fans in these rooms.   
 

What does MEV stand for?  


MEV stands for Mechanical Extract Ventilation. It is also referred to as central extract ventilation or demand controlled mechanical extract ventilation.  
 

How does MEV work? 

 

Mechanical Extract Ventilation (MEV)

A Mechanical Extract Ventilation (MEV) system provides continuous extraction of stale, moist air from all wet rooms within the home, such as bathrooms, kitchens and utility rooms.  

The single, low energy fan unit is typically installed in the loft space/hallway cupboard, with ducting running to each wet room, leading to extraction vents in each of those rooms. There is no noise from these vents as there would typically be with extractor fans. 

The fan runs continuously at a low ventilation rate and automatically boosts when higher humidity is detected (i.e. when showering). The system then returns to normal speed when the humidity levels drop. 

The extracted air is vented outside via a single duct and grille/cowl. 

 

Is MEV the right system for my home? 

 

For new build and self build homes, Mechanical Extract Ventilation (MEV) meets building control regulations under System 3 of the Ventilation Requirements. 

MEV is suitable for: 

  • New build projects (up to 300m2/ 3200 sq.ft, with 6 wet rooms or less) 
  • Full home renovations 
  • Those who want an easily installed, whole-house ventilation system 

Overall, the type of ventilation required is determined by several factors including: airtightness level, the construction type of the build and budget. 

For information on other ventilation options, including Heat Recovery Ventilation (HRV)  and Positive Input Ventilation (PIV), read our blog 'Meeting Building Control Requirements for New Build Homes'

For existing homes, our team of experts can advise you on the best system for your requirements. Get in touch for advice or to arrange your free surveys.
 

What are the benefits of an MEV system? 

 

An MEV system has many benefits, including: 

  • It is cost-effective for those with lower ventilation budgets 
  • Improves indoor air quality 
  • Easy to maintain and has low running costs 
  • There is no need for noisy extractor fans 
  • Prevents condensation and mould growth 
  • Energy savings as there is just one fan to run 

Do I need any other ventilation alongside my MEV system? 


When the stale air is extracted from wetrooms, it does need to be replaced with fresh air. This can be provided by openings such as window trickle vents, or via a Positive Input Ventilation unit (PIV). This unit usually sits in the loft space with a vent below in a central hallway location. Fresh, filtered air is drawn in and distributed throughout the home.   

Can Beam install the MEV system? 


We have a team of expert engineers available to professionally install your MEV system. If you would prefer to purchase the system on a DIY basis, we can provide design layout, all the necessary materials required and a system commissioning service (to meet building control requirements).  It is essential that the system is installed correctly to ensure optimal efficiency. Click here for more on the benefits of Mechanical Extract Ventilation (MEV) and details on installation of the system.


Get in touch 

For more information or to discuss ventilation options for your project, call our team on 02879632424 or use our contact form and we will be happy to help.