Single Room – Mechanical Ventilation Heat Recovery –  efficient and effective extraction.

> Unit cost £360 + Installation £360 = £720

On this page


  • Audit
  • Energy and moisture


  • Venting
  • Ducting
  • Backdraught shutter





Advice and support

  • Homework
  • Workshops


More often than not vents are dysfunctional and obsolete. inappropriate or ineffective they either need replaced with a functional solution or closed off altogether.

Kitchen extractors are most often not connected to the outside and it is unlikely a good backdraught shutter is fitted to prevent unwanted air ingress when not in use. Neither kitchen or bathroom vent can not push air more than 1.5 metres. If it’s being pushed up a chimney or out via an attic it is most likely to be causing more harm than good and damp will manifest all around the home.

Energy and moisture

  • Kitchen and extractor/ cooker hood. Is one fitted? Does it work? and if so does it connect to the outside? Has it been installed with a good backdraught shutter?
  • Bathroom extractor. Does it work? Is it connect to the outside? Has it been installed with a good backdraught shutter?
  • Do these extractors connect to the outside within less than 1.5m?
  • Are any of them collecting water in either the attic or the chimney?
  • Other vents – trickle vents in windows, night latches and obsolete vents. Do they need repairing or removing?


Is it usable? – What is the strategy for operating the extractor vent?

Extractors connected to come on with the room light are unlikely to be used during daylight.


Does it work?


Is it connected to the outside?


Is it less than 1.5m?
What is the exit route?
Does it need to be insulated?

Backdraught shutter

Vents and voids
Unwanted air ingress?

Plastic bag and a rubber band.

Without an effective back-draught shutter, cold air ingress can cause problems with moisture and mould, exacerbating symptoms that the installation of the vent was once installed to resolve.

Don’t beware the temporary measure. This 100mm diameter hole is allowing unimpeded air ingress into this bathroom. This air-ingress is creating cold spots with the capacity to attract warm moist air. The vent is exacerbating the problem it was installed to resolve.

Envirovent – neoprene backdraught shutter


Single Room – Mechanical Ventilation Heat Recovery (SR-MVHR)

Single Room – Mechanical Ventilation Heat Recovery.

A simple and effective solution for kitchens, bathrooms. Outside wall required.



Mechanical Ventilation Heat Recovery – (MVHR)

Alternatively, if it is not possible to install a wall-mounted unit such as in a ‘landlocked’ bathroom a small MVHR unit may be a better option. This unit is located outside of the room, extract moist air from the kitchen and bathroom, exchanges ait with the outside and returns fresh air to another room such as the bedrooms.



decentralised Mechanical Extractor Vent – (dMEV)

When direct access through an outside wall is not possible and longer ducting is required.





Further information




Advice and support

Trello – vents

> Voids